AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/09/11 12:37	flow	patch-triage	2m Args: null Results: { "EnableConfigs": [ "STRICT_KERNEL_RWX" ], "FocusSymbols": [ "__change_page_attr", "__should_split_large_page", "change_page_attr_set_clr", "set_memory_ro", "set_memory_rw", "set_memory_rox", "set_memory_nx", "set_memory_x" ], "KMSANReasoning": "The patch modifies `verify_rwx()` in `arch/x86/mm/pat/set_memory.c` to log a warning via `pr_warn_once` instead of triggering a full `WARN_ONCE` when a W^X violation is detected before kernel text has been marked read-only (`kernel_set_to_readonly` is false). \n\nThis change only touches logging and control flow based on an existing global boolean flag and scalar page-table protection values. It does not introduce any memory allocations, does not touch uninitialized heap/stack memory or structure padding, and does not expose any kernel data to user space. Therefore, there are no uninitialized memory risks, and KMSAN fuzzing is not required.", "NeedsKMSAN": false, "Reasoning": "The patch modifies the W^X permission verification logic (verify_rwx) within x86 Change Page Attributes (CPA) in arch/x86/mm/pat/set_memory.c. This is reachable core memory management code executed whenever kernel page protections are adjusted (such as via BPF JIT, ftrace, module loading/unloading, or driver memory attribute changes). It introduces new conditional warning behavior when kernel_set_to_readonly is false.", "WorthFuzzing": true }
1/1	2026/09/11 12:37	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit bdd6d4eedaaf432f7fba37c2efc88b8459af8020\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Fri Sep 11 12:37:43 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c\nindex b3060000da8d1..a4f7fe69e6922 100644\n--- a/arch/x86/mm/pat/set_memory.c\n+++ b/arch/x86/mm/pat/set_memory.c\n@@ -697,6 +697,21 @@ static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long star\n \t\treturn new;\n \n \tend = start + npg * PAGE_SIZE - 1;\n+\n+\t/\n+\t If the kernel text is still RWX, gently complain, this could be a\n+\t * false positive.\n+\t * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,\n+\t * the warning can be removed completely.\n+\t */\n+\tif (!kernel_set_to_readonly) {\n+\t\tpr_warn_once(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n+\t\t (unsigned long long)pgprot_val(old),\n+\t\t (unsigned long long)pgprot_val(new),\n+\t\t start, end, pfn);\n+\t\treturn new;\n+\t}\n+\n \tWARN_ONCE(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n \t\t (unsigned long long)pgprot_val(old),\n \t\t (unsigned long long)pgprot_val(new),\n" }
2/1	2026/09/11 12:37	agent	patch-evaluator	1m Model: core Args: null Results: { "EnableConfigs": [ "STRICT_KERNEL_RWX" ], "FocusSymbols": [ "__change_page_attr", "__should_split_large_page", "change_page_attr_set_clr", "set_memory_ro", "set_memory_rw", "set_memory_rox", "set_memory_nx", "set_memory_x" ], "Reasoning": "The patch modifies the W^X permission verification logic (verify_rwx) within x86 Change Page Attributes (CPA) in arch/x86/mm/pat/set_memory.c. This is reachable core memory management code executed whenever kernel page protections are adjusted (such as via BPF JIT, ftrace, module loading/unloading, or driver memory attribute changes). It introduces new conditional warning behavior when kernel_set_to_readonly is false.", "WorthFuzzing": true } Instruction: You are an expert Linux kernel maintainer and security engineer. Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on internal assumptions. You must actively use your code access tools to inspect the actual source code, callers, and surrounding context. ================================================================================ 1. CORE TRIAGE PHILOSOPHY ================================================================================ The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs, and newly triggered assertions introduced by the patch series. - REACHABILITY IS THE PRIMARY GATE: Fuzzing can only discover bugs in code that can actually execute in standard virtualized environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap). If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed, regardless of whether it adds assertions or complex logic. - DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS: Patch authors routinely label changes as "cleanups", "refactorings", or state "No functional change intended". Do NOT take these claims at face value. Code refactorings that rearrange logic, introduce helper functions, or alter state management in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs. If reachable executable code is modified or refactored, it MUST be fuzzed. - NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED: When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON, VM_WARN_ON, BUG_ON, lockdep_assert) in reachable code paths, it enforces new or stricter invariants. Even if the author believes the invariant always holds, fuzzing is essential to verify whether an unusual sequence of operations can violate it. ================================================================================ 2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA) ================================================================================ Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories: - Non-kernel and non-executable changes: * Modifications to Documentation/, comments, or spelling fixes. * User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/) that do not affect the compiled kernel image (vmlinux) or kernel modules. * Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints that do not alter control flow or data structures. * Build system or Kconfig changes that do not alter compiled C logic. - Structurally unreachable hardware: * Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed, ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU. - Unreachable execution paths: * Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during physical PCI hot-unplug or manual sysfs driver unbinding. * Code paths exclusive to architectures other than the target architecture. ================================================================================ 3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA) ================================================================================ Return WorthFuzzing=true whenever the patch touches reachable executable code, including: - Core Subsystems: * Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/), BPF, scheduler, core networking, VFS, or syscall handling. - Refactorings and Code Cleanups: * Any restructuring of reachable data structures, helper abstractions, or algorithm flows. - Runtime Assertions and Defensive Checks: * Any introduction or alteration of assertions (WARN_ON, VM_WARN_ON, BUG_ON, etc.) in reachable paths. - Reachable Drivers and Protocols: Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.). ================================================================================ 4. EXTRACTING FocusSymbols (PREVENTING DILUTION) ================================================================================ When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer: - AVOID UBIQUITOUS LIFECYCLE HOT-PATHS: Do NOT list generic, ubiquitous functions called by almost every program in the corpus (including, but not limited to: general memory allocators and deallocators, page fault and trap handlers, or core synchronization primitives; this is not an exhaustive list). Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused", which severely dilutes fuzzing effort away from the actual changes. - TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS: List functions that specifically implement the logic being added or altered, or direct API entrypoints for the subsystem feature under review. - HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h): Compiler-inlined static functions (such as static inlines in mm/.h or include/linux/.h) lack distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters. If the changes are primarily in static inline helpers, identify non-static, feature-specific caller functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers). ================================================================================ 5. IDENTIFYING EnableConfigs ================================================================================ Identify any specific CONFIG_ options required to properly compile and reach the modified code: - Inspect Kconfig files and #ifdef guards; do not make assumptions. - Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed. - Strip any 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4"). Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit bdd6d4eedaaf432f7fba37c2efc88b8459af8020 Author: syz-cluster <triage@syzkaller.com> Date: Fri Sep 11 12:37:43 2026 +0000 syz-cluster: applied patch under review diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index b3060000da8d1..a4f7fe69e6922 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -697,6 +697,21 @@ static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long star return new; end = start + npg * PAGE_SIZE - 1; + + /* + * If the kernel text is still RWX, gently complain, this could be a + * false positive. + * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX, + * the warning can be removed completely. + */ + if (!kernel_set_to_readonly) { + pr_warn_once(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n", + (unsigned long long)pgprot_val(old), + (unsigned long long)pgprot_val(new), + start, end, pfn); + return new; + } + WARN_ONCE(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n", (unsigned long long)pgprot_val(old), (unsigned long long)pgprot_val(new),
3/2	2026/09/11 12:37	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 3124 output: 43 thoughts: 74 Thoughts: Analyzing the Patch and Associated Tools Alright, let's dive in. My first instinct is always to get a solid grasp of the patch itself, of course. I need to understand the specifics of what's changed and then put that into context. The logical starting point for this is to examine the relevant code, which in this case seems to be within `arch/x86/mm/pat/set_memory.c`. I will then go ahead and use `read-file` or `grepper` on `arch/x86/mm/pat/set_memory.c`. I have a feeling that inspecting this file will be key to understanding the patch's impact.
4/2	2026/09/11 12:37	tool	read-file	0m Args: { "File": "arch/x86/mm/pat/set_memory.c", "FirstLine": 680, "LineCount": 60 } Results: { "Contents": " 680:\t\t * detection and enforcement there.\n 681:\t\t /\n 682:\t\tif (IS_ENABLED(CONFIG_X86_32))\n 683:\t\t\treturn new;\n 684:\t\n 685:\t\t/ Only verify when NX is supported: /\n 686:\t\tif (!(__supported_pte_mask \u0026 _PAGE_NX))\n 687:\t\t\treturn new;\n 688:\t\n 689:\t\tif (!((pgprot_val(old) ^ pgprot_val(new)) \u0026 (_PAGE_RW \| _PAGE_NX)))\n 690:\t\t\treturn new;\n 691:\t\n 692:\t\tif ((pgprot_val(new) \u0026 (_PAGE_RW \| _PAGE_NX)) != _PAGE_RW)\n 693:\t\t\treturn new;\n 694:\t\n 695:\t\t/ Non-leaf translation entries can disable writing or execution. /\n 696:\t\tif (!rw \|\| nx)\n 697:\t\t\treturn new;\n 698:\t\n 699:\t\tend = start + npg PAGE_SIZE - 1;\n 700:\t\n 701:\t\t/\n 702:\t\t If the kernel text is still RWX, gently complain, this could be a\n 703:\t\t * false positive.\n 704:\t\t * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,\n 705:\t\t * the warning can be removed completely.\n 706:\t\t /\n 707:\t\tif (!kernel_set_to_readonly) {\n 708:\t\t\tpr_warn_once(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 709:\t\t\t (unsigned long long)pgprot_val(old),\n 710:\t\t\t (unsigned long long)pgprot_val(new),\n 711:\t\t\t start, end, pfn);\n 712:\t\t\treturn new;\n 713:\t\t}\n 714:\t\n 715:\t\tWARN_ONCE(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 716:\t\t\t (unsigned long long)pgprot_val(old),\n 717:\t\t\t (unsigned long long)pgprot_val(new),\n 718:\t\t\t start, end, pfn);\n 719:\t\n 720:\t\t/\n 721:\t\t * For now, allow all permission change attempts by returning the\n 722:\t\t * attempted permissions. This can 'return old' to actively\n 723:\t\t * refuse the permission change at a later time.\n 724:\t\t /\n 725:\t\treturn new;\n 726:\t}\n 727:\t\n 728:\t/\n 729:\t * Lookup the page table entry for a virtual address in a specific pgd.\n 730:\t * Return a pointer to the entry (or NULL if the entry does not exist),\n 731:\t * the level of the entry, and the effective NX and RW bits of all\n 732:\t * page table levels.\n 733:\t /\n 734:\tpte_t lookup_address_in_pgd_attr(pgd_t pgd, unsigned long address,\n 735:\t\t\t\t\t unsigned int level, bool nx, bool rw)\n 736:\t{\n 737:\t\tp4d_t p4d;\n 738:\t\tpud_t pud;\n 739:\t\tpmd_t *pmd;\n" }
5/2	2026/09/11 12:37	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 4378 output: 39 thoughts: 25 Thoughts: Here's my take on those thoughts: Analyzing `verify_rwx` Usage Alright, time to get down to brass tacks. I need to understand the scope of the `verify_rwx` function and how it's being utilized within this codebase. To get a clear picture of its influence, I'm going to reach for the tried and true `grep` command. Specifically, I'll search for `verify_rwx` to identify every instance where it's invoked. This will illuminate the surrounding context and reveal the areas of the code that depend on its functionality. This quick scan will set the stage for a deeper dive, allowing me to understand where this function fits into the bigger picture.
6/2	2026/09/11 12:37	tool	grepper	0m Args: { "Expression": "verify_rwx", "PathPrefix": "arch/x86/mm/pat/set_memory.c" } Results: { "Output": "arch/x86/mm/pat/set_memory.c=623=static inline pgprot_t static_protections(pgprot_t prot, unsigned long start,\n--\narch/x86/mm/pat/set_memory.c-670- /\narch/x86/mm/pat/set_memory.c:671:static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,\narch/x86/mm/pat/set_memory.c-672-\t\t\t\t unsigned long pfn, unsigned long npg,\n--\narch/x86/mm/pat/set_memory.c=943=static int __should_split_large_page(pte_t kpte, unsigned long address,\n--\narch/x86/mm/pat/set_memory.c-1066-\narch/x86/mm/pat/set_memory.c:1067:\tnew_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages,\narch/x86/mm/pat/set_memory.c-1068-\t\t\t nx, rw);\n--\narch/x86/mm/pat/set_memory.c=1850=static int __change_page_attr(struct cpa_data *cpa, int primary)\n--\narch/x86/mm/pat/set_memory.c-1881-\narch/x86/mm/pat/set_memory.c:1882:\t\tnew_prot = verify_rwx(old_prot, new_prot, address, pfn, 1,\narch/x86/mm/pat/set_memory.c-1883-\t\t\t\t nx, rw);\n" }
7/2	2026/09/11 12:37	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 5045 output: 21 thoughts: 38 Thoughts: Here's my take on those thoughts: Analyzing Kernel Functionality Okay, let's dive in. My immediate thought is, "Right, I need to understand what's happening here." The goal is to get a handle on this particular code. Specifically, I'm thinking about the interactions between `verify_rwx` and `kernel_set_to_readonly`. I need to figure out what each of these functions does, and how they relate. Given that the goal is to fully analyze the code, it makes sense to start with `kernel_set_to_readonly`. Let's search for the definition and usage of that function first. A good solid definition will give me the best foundation to understand the context and intent of the code.
8/2	2026/09/11 12:37	tool	grepper	0m Args: { "Expression": "kernel_set_to_readonly" } Results: { "Output": "arch/parisc/mm/init.c=112=static void __init setup_bootmem(void)\n--\narch/parisc/mm/init.c-340-\narch/parisc/mm/init.c:341:static bool kernel_set_to_readonly;\narch/parisc/mm/init.c-342-\narch/parisc/mm/init.c=343=static void __ref map_pages(unsigned long start_vaddr,\n--\narch/parisc/mm/init.c-403-\t\t\t\t\tprot = PAGE_KERNEL;\narch/parisc/mm/init.c:404:\t\t\t\t} else if (!kernel_set_to_readonly) {\narch/parisc/mm/init.c-405-\t\t\t\t\t/* still initializing, allow writing to RO memory /\n--\narch/parisc/mm/init.c=489=void mark_rodata_ro(void)\n--\narch/parisc/mm/init.c-496-\narch/parisc/mm/init.c:497:\tkernel_set_to_readonly = true;\narch/parisc/mm/init.c-498-\tmap_pages(start, __pa(start), end - start, PAGE_KERNEL, 0);\n--\narch/x86/include/asm/set_memory.h=92=bool kernel_page_present(struct page page);\narch/x86/include/asm/set_memory.h-93-\narch/x86/include/asm/set_memory.h:94:extern int kernel_set_to_readonly;\narch/x86/include/asm/set_memory.h-95-\n--\narch/x86/mm/init_32.c=692=void __init mem_init(void)\n--\narch/x86/mm/init_32.c-720-\narch/x86/mm/init_32.c:721:int kernel_set_to_readonly __read_mostly;\narch/x86/mm/init_32.c-722-\n--\narch/x86/mm/init_32.c=740=void mark_rodata_ro(void)\n--\narch/x86/mm/init_32.c-748-\narch/x86/mm/init_32.c:749:\tkernel_set_to_readonly = 1;\narch/x86/mm/init_32.c-750-\n--\narch/x86/mm/init_64.c=1343=void __init mem_init(void)\n--\narch/x86/mm/init_64.c-1356-\narch/x86/mm/init_64.c:1357:int kernel_set_to_readonly;\narch/x86/mm/init_64.c-1358-\narch/x86/mm/init_64.c=1359=void mark_rodata_ro(void)\n--\narch/x86/mm/init_64.c-1371-\narch/x86/mm/init_64.c:1372:\tkernel_set_to_readonly = 1;\narch/x86/mm/init_64.c-1373-\n--\narch/x86/mm/pat/set_memory.c=507=static pgprotval_t protect_pci_bios(unsigned long spfn, unsigned long epfn)\n--\narch/x86/mm/pat/set_memory.c-515- * aliases. This also includes __ro_after_init, so do not enforce until\narch/x86/mm/pat/set_memory.c:516: * kernel_set_to_readonly is true.\narch/x86/mm/pat/set_memory.c-517- /\narch/x86/mm/pat/set_memory.c=518=static pgprotval_t protect_rodata(unsigned long spfn, unsigned long epfn)\n--\narch/x86/mm/pat/set_memory.c-527-\narch/x86/mm/pat/set_memory.c:528:\tif (kernel_set_to_readonly \u0026\u0026 overlaps(spfn, epfn, spfn_ro, epfn_ro))\narch/x86/mm/pat/set_memory.c-529-\t\treturn _PAGE_RW;\n--\narch/x86/mm/pat/set_memory.c=541=static pgprotval_t protect_kernel_text(unsigned long start, unsigned long end)\n--\narch/x86/mm/pat/set_memory.c-552-/\narch/x86/mm/pat/set_memory.c:553: * Once the kernel maps the text as RO (kernel_set_to_readonly is set),\narch/x86/mm/pat/set_memory.c-554- * kernel text mappings for the large page aligned text, rodata sections\n--\narch/x86/mm/pat/set_memory.c=561=static pgprotval_t protect_kernel_text_ro(unsigned long start,\n--\narch/x86/mm/pat/set_memory.c-567-\narch/x86/mm/pat/set_memory.c:568:\tif (!kernel_set_to_readonly \|\| !overlaps(start, end, t_start, t_end))\narch/x86/mm/pat/set_memory.c-569-\t\treturn 0;\n--\narch/x86/mm/pat/set_memory.c=671=static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,\n--\narch/x86/mm/pat/set_memory.c-706-\t */\narch/x86/mm/pat/set_memory.c:707:\tif (!kernel_set_to_readonly) {\narch/x86/mm/pat/set_memory.c-708-\t\tpr_warn_once(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n" }
9/2	2026/09/11 12:37	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 6868 output: 20 thoughts: 143 Thoughts: Analyzing the Read-Only Data Marking Okay, let's break this down. My initial understanding is that `mark_rodata_ro()` gets invoked during the kernel's boot process, specifically within the functions `mark_readonly()` or directly as `mark_rodata_ro()`. The crucial piece here is that when this function executes during boot, the variable `kernel_set_to_readonly` gets set to a value of 1. The interesting thing is that after the boot sequence completes, during the standard runtime of the kernel, and even during fuzzing efforts, this `kernel_set_to_readonly` variable always retains its value of 1. But, wait a second... this feels like it might be an oversimplification. Is it truly the case that `kernel_set_to_readonly` is never zero after the initial boot? I need to clarify if there's a transient period during the very early stages of the boot process where this variable might be 0, before being initialized to 1. This could be key to understanding potential vulnerabilities or unexpected behavior. Therefore, I need to verify when `mark_rodata_ro()` is actually called in the boot sequence. Let's do a quick grep search to confirm the call site and see if there are any subtle variations in the call paths.
10/2	2026/09/11 12:38	tool	grepper	0m Args: { "Expression": "mark_rodata_ro" } Results: { "Output": "arch/arm/mm/init.c=392=static void fix_kernmem_perms(void)\n--\narch/arm/mm/init.c-396-\narch/arm/mm/init.c:397:static int __mark_rodata_ro(void unused)\narch/arm/mm/init.c-398-{\n--\narch/arm/mm/init.c-402-\narch/arm/mm/init.c:403:void mark_rodata_ro(void)\narch/arm/mm/init.c-404-{\narch/arm/mm/init.c:405:\tstop_machine(__mark_rodata_ro, NULL, NULL);\narch/arm/mm/init.c-406-\tarm_debug_checkwx();\n--\narch/arm64/mm/mmu.c=1180=static void __init map_mem(void)\n--\narch/arm64/mm/mmu.c-1253-\narch/arm64/mm/mmu.c:1254:void mark_rodata_ro(void)\narch/arm64/mm/mmu.c-1255-{\n--\narch/parisc/mm/init.c=451=void free_initmem(void)\n--\narch/parisc/mm/init.c-488-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/parisc/mm/init.c:489:void mark_rodata_ro(void)\narch/parisc/mm/init.c-490-{\n--\narch/powerpc/include/asm/book3s/64/hash.h=152=static inline int hash__p4d_bad(p4d_t p4d)\n--\narch/powerpc/include/asm/book3s/64/hash.h-156-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/include/asm/book3s/64/hash.h:157:extern void hash__mark_rodata_ro(void);\narch/powerpc/include/asm/book3s/64/hash.h-158-extern void hash__mark_initmem_nx(void);\n--\narch/powerpc/include/asm/book3s/64/radix.h-141-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/include/asm/book3s/64/radix.h:142:extern void radix__mark_rodata_ro(void);\narch/powerpc/include/asm/book3s/64/radix.h-143-extern void radix__mark_initmem_nx(void);\n--\narch/powerpc/mm/book3s32/mmu.c=196=int mmu_mark_initmem_nx(void)\n--\narch/powerpc/mm/book3s32/mmu.c-235-\narch/powerpc/mm/book3s32/mmu.c:236:int mmu_mark_rodata_ro(void)\narch/powerpc/mm/book3s32/mmu.c-237-{\n--\narch/powerpc/mm/book3s64/hash_pgtable.c=524=static bool hash__change_memory_range(unsigned long start, unsigned long end,\n--\narch/powerpc/mm/book3s64/hash_pgtable.c-564-\narch/powerpc/mm/book3s64/hash_pgtable.c:565:void hash__mark_rodata_ro(void)\narch/powerpc/mm/book3s64/hash_pgtable.c-566-{\n--\narch/powerpc/mm/book3s64/radix_pgtable.c=188=static void radix__change_memory_range(unsigned long start, unsigned long end,\n--\narch/powerpc/mm/book3s64/radix_pgtable.c-230-\narch/powerpc/mm/book3s64/radix_pgtable.c:231:void radix__mark_rodata_ro(void)\narch/powerpc/mm/book3s64/radix_pgtable.c-232-{\n--\narch/powerpc/mm/mmu_decl.h=163=int mmu_mark_initmem_nx(void);\narch/powerpc/mm/mmu_decl.h:164:int mmu_mark_rodata_ro(void);\narch/powerpc/mm/mmu_decl.h-165-#else\narch/powerpc/mm/mmu_decl.h=166=static inline int mmu_mark_initmem_nx(void) { return 0; }\narch/powerpc/mm/mmu_decl.h:167:static inline int mmu_mark_rodata_ro(void) { return 0; }\narch/powerpc/mm/mmu_decl.h-168-#endif\n--\narch/powerpc/mm/nohash/8xx.c=171=int mmu_mark_initmem_nx(void)\n--\narch/powerpc/mm/nohash/8xx.c-188-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/mm/nohash/8xx.c:189:int mmu_mark_rodata_ro(void)\narch/powerpc/mm/nohash/8xx.c-190-{\n--\narch/powerpc/mm/nohash/e500.c=266=void __init adjust_total_lowmem(void)\n--\narch/powerpc/mm/nohash/e500.c-287-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/mm/nohash/e500.c:288:int mmu_mark_rodata_ro(void)\narch/powerpc/mm/nohash/e500.c-289-{\n--\narch/powerpc/mm/nohash/e500.c=301=int mmu_mark_initmem_nx(void)\narch/powerpc/mm/nohash/e500.c-302-{\narch/powerpc/mm/nohash/e500.c:303:\t/ Everything is done in mmu_mark_rodata_ro() /\narch/powerpc/mm/nohash/e500.c-304-\treturn 0;\n--\narch/powerpc/mm/pgtable_32.c=145=void mark_initmem_nx(void)\n--\narch/powerpc/mm/pgtable_32.c-153-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/mm/pgtable_32.c:154:static int __mark_rodata_ro(void)\narch/powerpc/mm/pgtable_32.c-155-{\n--\narch/powerpc/mm/pgtable_32.c-161-\tif (v_block_mapped((unsigned long)_stext + 1))\narch/powerpc/mm/pgtable_32.c:162:\t\treturn mmu_mark_rodata_ro();\narch/powerpc/mm/pgtable_32.c-163-\n--\narch/powerpc/mm/pgtable_32.c-174-\narch/powerpc/mm/pgtable_32.c:175:void mark_rodata_ro(void)\narch/powerpc/mm/pgtable_32.c-176-{\narch/powerpc/mm/pgtable_32.c:177:\tint err = __mark_rodata_ro();\narch/powerpc/mm/pgtable_32.c-178-\n--\narch/powerpc/mm/pgtable_64.c=126=struct page pmd_page(pmd_t pmd)\n--\narch/powerpc/mm/pgtable_64.c-141-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/mm/pgtable_64.c:142:void mark_rodata_ro(void)\narch/powerpc/mm/pgtable_64.c-143-{\n--\narch/powerpc/mm/pgtable_64.c-149-\tif (radix_enabled())\narch/powerpc/mm/pgtable_64.c:150:\t\tradix__mark_rodata_ro();\narch/powerpc/mm/pgtable_64.c-151-\telse\narch/powerpc/mm/pgtable_64.c:152:\t\thash__mark_rodata_ro();\narch/powerpc/mm/pgtable_64.c-153-}\n--\narch/riscv/mm/init.c=732=static __meminit pgprot_t pgprot_from_va(uintptr_t va)\n--\narch/riscv/mm/init.c-740-\t * written.\narch/riscv/mm/init.c:741:\t * And rodata section is marked readonly in mark_rodata_ro.\narch/riscv/mm/init.c-742-\t /\n--\narch/riscv/mm/init.c-748-\narch/riscv/mm/init.c:749:void mark_rodata_ro(void)\narch/riscv/mm/init.c-750-{\n--\narch/s390/mm/init.c=101=void __init paging_init(void)\n--\narch/s390/mm/init.c-106-\narch/s390/mm/init.c:107:void mark_rodata_ro(void)\narch/s390/mm/init.c-108-{\n--\narch/um/kernel/mem.c=131=DECLARE_VM_GET_PAGE_PROT\narch/um/kernel/mem.c-132-\narch/um/kernel/mem.c:133:void mark_rodata_ro(void)\narch/um/kernel/mem.c-134-{\n--\narch/x86/mm/init_32.c=723=static void mark_nxdata_nx(void)\n--\narch/x86/mm/init_32.c-739-\narch/x86/mm/init_32.c:740:void mark_rodata_ro(void)\narch/x86/mm/init_32.c-741-{\n--\narch/x86/mm/init_64.c=1357=int kernel_set_to_readonly;\narch/x86/mm/init_64.c-1358-\narch/x86/mm/init_64.c:1359:void mark_rodata_ro(void)\narch/x86/mm/init_64.c-1360-{\n--\ninclude/linux/cache.h-55- __ro_after_init is used to mark things that are read-only after init (i.e.\ninclude/linux/cache.h:56: * after mark_rodata_ro() has been called). These are effectively read-only,\ninclude/linux/cache.h-57- * but may get written to during init, so can't live in .rodata (via \"const\").\n--\ninclude/linux/init.h=165=extern bool rodata_enabled;\ninclude/linux/init.h:166:void mark_rodata_ro(void);\ninclude/linux/init.h-167-\n--\ninclude/linux/rodata_test.h-2-/\ninclude/linux/rodata_test.h:3: rodata_test.h: functional test for mark_rodata_ro function\ninclude/linux/rodata_test.h-4- \n--\ninit/main.c=1521=static void mark_readonly(void)\n--\ninit/main.c-1531-\t\tjump_label_init_ro();\ninit/main.c:1532:\t\tmark_rodata_ro();\ninit/main.c-1533-\t\tdebug_checkwx();\n--\nkernel/module/main.c=3088=static noinline int do_init_module(struct module mod)\n--\nkernel/module/main.c-3188-\t * mappings which won't be cleaned up until do_free_init() runs. Any\nkernel/module/main.c:3189:\t * code such as mark_rodata_ro() which depends on those mappings to\nkernel/module/main.c-3190-\t * be cleaned up needs to sync with the queued work by invoking\n--\nmm/rodata_test.c-2-/\nmm/rodata_test.c:3: rodata_test.c: functional test for mark_rodata_ro function\nmm/rodata_test.c-4- *\n" }
11/2	2026/09/11 12:38	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 10589 output: 34 thoughts: 58 Thoughts: Here's my analysis of what I'm looking at, from my expert perspective: Investigating `mark_readonly` During Kernel Boot Alright, so I need to track down when and where `mark_readonly` is being called, which, as I recall, likely pertains to memory regions. The hint is in `init/main.c`, and more specifically, it's triggered during boot, right around the time the kernel is initializing, before it hands control over to the init process and starts freeing memory allocated during the initial boot sequence. That narrows it down considerably. I'm going to jump into `init/main.c` now and zoom in around line 1521, to find the exact context of that call and try to understand what specific memory regions are being made read-only at that stage. This should give me a good handle on how the kernel is setting up memory protection early on.
12/2	2026/09/11 12:38	tool	read-file	0m Args: { "File": "init/main.c", "FirstLine": 1515, "LineCount": 40 } Results: { "Contents": "1515:\t\t\tpr_warn(\"Invalid option string for rodata: '%s'\\n\", str);\n1516:\t\treturn 0;\n1517:\t}\n1518:\tearly_param(\"rodata\", set_debug_rodata);\n1519:\t#endif\n1520:\t\n1521:\tstatic void mark_readonly(void)\n1522:\t{\n1523:\t\tif (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) \u0026\u0026 rodata_enabled) {\n1524:\t\t\t/\n1525:\t\t\t load_module() results in W+X mappings, which are cleaned\n1526:\t\t\t * up with init_free_wq. Let's make sure that queued work is\n1527:\t\t\t * flushed so that we don't hit false positives looking for\n1528:\t\t\t * insecure pages which are W+X.\n1529:\t\t\t /\n1530:\t\t\tflush_module_init_free_work();\n1531:\t\t\tjump_label_init_ro();\n1532:\t\t\tmark_rodata_ro();\n1533:\t\t\tdebug_checkwx();\n1534:\t\t\trodata_test();\n1535:\t\t} else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {\n1536:\t\t\tpr_info(\"Kernel memory protection disabled.\\n\");\n1537:\t\t} else if (IS_ENABLED(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)) {\n1538:\t\t\tpr_warn(\"Kernel memory protection not selected by kernel config.\\n\");\n1539:\t\t} else {\n1540:\t\t\tpr_warn(\"This architecture does not have kernel memory protection.\\n\");\n1541:\t\t}\n1542:\t}\n1543:\t\n1544:\tvoid __weak free_initmem(void)\n1545:\t{\n1546:\t\tfree_initmem_default(POISON_FREE_INITMEM);\n1547:\t}\n1548:\t\n1549:\tstatic int __ref kernel_init(void unused)\n1550:\t{\n1551:\t\tint ret;\n1552:\t\n1553:\t\tinit_userspace_fs();\n1554:\t\n" }
13/2	2026/09/11 12:38	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 11468 output: 18 thoughts: 318 Thoughts: Investigating a Kernel W^X Violation Okay, so I'm looking at this `verify_rwx` function and a potential Write XOR Execute (W^X) violation. The crux of the issue seems to be tied to the `kernel_set_to_readonly` flag, which indicates whether read-only data sections have been properly marked as such. I'm wondering what happens in a few specific scenarios. First, let's explore what occurs when `!rodata_enabled`, which essentially means the kernel is booted with `rodata=off` on the kernel command line. If that's the case, then `mark_rodata_ro()` is never invoked. Consequently, `kernel_set_to_readonly` remains 0. This lack of setting the flag could be the root cause. Now, what if there's a situation where early boot code, using `set_memory_` calls, modifies memory regions before* `mark_rodata_ro()` is even called? This could also lead to similar problems. I need to keep that timing in mind. I'm seeing that `verify_rwx` is firing `WARN_ONCE` during boot, indicating a potential W^X issue. This patch modifies the warning logic to include the `kernel_set_to_readonly` check. The idea is, if the flag isn't set, we emit a specific warning, and otherwise issue the general W^X warning. Wait a second, before I dig too deep into the code, I should probably consult `git log` or the commit history around `verify_rwx`. Understanding the context of the change—what problems it was intended to solve and what assumptions were made—will give me a clearer picture of what I'm dealing with. That's the first thing I need to do.
14/2	2026/09/11 12:38	tool	grepper	0m Args: { "Expression": "verify_rwx" } Results: { "Output": "arch/x86/mm/pat/set_memory.c=623=static inline pgprot_t static_protections(pgprot_t prot, unsigned long start,\n--\narch/x86/mm/pat/set_memory.c-670- /\narch/x86/mm/pat/set_memory.c:671:static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,\narch/x86/mm/pat/set_memory.c-672-\t\t\t\t unsigned long pfn, unsigned long npg,\n--\narch/x86/mm/pat/set_memory.c=943=static int __should_split_large_page(pte_t kpte, unsigned long address,\n--\narch/x86/mm/pat/set_memory.c-1066-\narch/x86/mm/pat/set_memory.c:1067:\tnew_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages,\narch/x86/mm/pat/set_memory.c-1068-\t\t\t nx, rw);\n--\narch/x86/mm/pat/set_memory.c=1850=static int __change_page_attr(struct cpa_data *cpa, int primary)\n--\narch/x86/mm/pat/set_memory.c-1881-\narch/x86/mm/pat/set_memory.c:1882:\t\tnew_prot = verify_rwx(old_prot, new_prot, address, pfn, 1,\narch/x86/mm/pat/set_memory.c-1883-\t\t\t\t nx, rw);\n" }
15/2	2026/09/11 12:38	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 12648 output: 43 thoughts: 34 Thoughts: Here's my summary, as though I'm reading and processing the provided information: Analyzing `verify_rwx` and Context Okay, so we're diving into the `verify_rwx` function, which implies some kind of memory access validation, likely related to read-write-execute permissions. The fact that it's nestled within `arch/x86/mm/pat/set_memory.c` immediately narrows the scope. This suggests we're dealing with the x86 architecture, memory management, potentially including Page Attribute Table (PAT) manipulation, and particularly, the setting of memory attributes. This is a critical area for security and performance optimization, so I need to understand the nuances of how it's implemented. I need to understand the logic flow, the types of validations done and how permissions are enforced. I'll need to examine the function's arguments, return values, and any side effects it may have, such as error reporting or changes to data structures. I'll pay close attention to the data types used and their sizes, as these can tell a lot about the intended usage and potential vulnerabilities. Time to dig in and understand this thoroughly.
16/2	2026/09/11 12:38	tool	read-file	0m Args: { "File": "arch/x86/mm/pat/set_memory.c", "FirstLine": 660, "LineCount": 70 } Results: { "Contents": " 660:\t\n 661:\t\tres = protect_rodata(pfn, pfn + npg - 1);\n 662:\t\tcheck_conflict(warnlvl, prot, res, start, end, pfn, \"Rodata RO\");\n 663:\t\tforbidden \|= res;\n 664:\t\n 665:\t\treturn __pgprot(pgprot_val(prot) \u0026 ~forbidden);\n 666:\t}\n 667:\t\n 668:\t/\n 669:\t Validate strict W^X semantics.\n 670:\t /\n 671:\tstatic inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,\n 672:\t\t\t\t\t unsigned long pfn, unsigned long npg,\n 673:\t\t\t\t\t bool nx, bool rw)\n 674:\t{\n 675:\t\tunsigned long end;\n 676:\t\n 677:\t\t/\n 678:\t\t * 32-bit has some unfixable W+X issues, like EFI code\n 679:\t\t * and writeable data being in the same page. Disable\n 680:\t\t * detection and enforcement there.\n 681:\t\t /\n 682:\t\tif (IS_ENABLED(CONFIG_X86_32))\n 683:\t\t\treturn new;\n 684:\t\n 685:\t\t/ Only verify when NX is supported: /\n 686:\t\tif (!(__supported_pte_mask \u0026 _PAGE_NX))\n 687:\t\t\treturn new;\n 688:\t\n 689:\t\tif (!((pgprot_val(old) ^ pgprot_val(new)) \u0026 (_PAGE_RW \| _PAGE_NX)))\n 690:\t\t\treturn new;\n 691:\t\n 692:\t\tif ((pgprot_val(new) \u0026 (_PAGE_RW \| _PAGE_NX)) != _PAGE_RW)\n 693:\t\t\treturn new;\n 694:\t\n 695:\t\t/ Non-leaf translation entries can disable writing or execution. /\n 696:\t\tif (!rw \|\| nx)\n 697:\t\t\treturn new;\n 698:\t\n 699:\t\tend = start + npg PAGE_SIZE - 1;\n 700:\t\n 701:\t\t/\n 702:\t\t If the kernel text is still RWX, gently complain, this could be a\n 703:\t\t * false positive.\n 704:\t\t * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,\n 705:\t\t * the warning can be removed completely.\n 706:\t\t /\n 707:\t\tif (!kernel_set_to_readonly) {\n 708:\t\t\tpr_warn_once(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 709:\t\t\t (unsigned long long)pgprot_val(old),\n 710:\t\t\t (unsigned long long)pgprot_val(new),\n 711:\t\t\t start, end, pfn);\n 712:\t\t\treturn new;\n 713:\t\t}\n 714:\t\n 715:\t\tWARN_ONCE(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 716:\t\t\t (unsigned long long)pgprot_val(old),\n 717:\t\t\t (unsigned long long)pgprot_val(new),\n 718:\t\t\t start, end, pfn);\n 719:\t\n 720:\t\t/\n 721:\t\t * For now, allow all permission change attempts by returning the\n 722:\t\t * attempted permissions. This can 'return old' to actively\n 723:\t\t * refuse the permission change at a later time.\n 724:\t\t /\n 725:\t\treturn new;\n 726:\t}\n 727:\t\n 728:\t/\n 729:\t * Lookup the page table entry for a virtual address in a specific pgd.\n" }
17/2	2026/09/11 12:38	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 14083 output: 30 thoughts: 1115 Thoughts: Fuzzing Evaluation for the CPA Patch Okay, let's break this down. My goal is to determine if this patch, specifically concerning `arch/x86/mm/pat/set_memory.c`, warrants fuzzing. This is a core subsystem related to x86 Memory Management and Change Page Attributes (CPA), so my initial instinct is to give it a close look. First, the core triage philosophy needs to be considered. The primary goal of fuzzing is to unearth crashes, regressions, or newly exposed bugs, particularly those introduced by the patch. The key here is reachability – can the code actually execute in a standard virtualized environment like GCE or QEMU, or via emulated devices? The documentation stresses not trusting "no functional change" or refactoring claims blindly, and that new/modified assertions must be fuzzed if they're in reachable code. That's a strong indicator. Now let's consider the negative criteria. The patch would be ignored if the code modified is strictly non-kernel and non-executable, decorative logging, structurally unreachable hardware, or unreachable execution paths. That last point – unreachable execution paths – is important. Driver teardown callbacks only used during hot-unplug, or code specific to other architectures are out. Then, there are the positive criteria. We definitely want to fuzz if the patch touches reachable executable code. This includes any modifications in memory management, locking, BPF, the scheduler, core networking, VFS, or syscall handling. Refactoring reachable data structures or algorithm flows is also a trigger. Finally, and this is crucial, the introduction or modification of assertions (WARN_ON, etc.) in reachable code paths mandates* fuzzing. Now, let's analyze the patch itself. The change introduces an `if (!kernel_set_to_readonly)` condition within the `verify_rwx()` function. This affects how the "W^X violation" is handled. Previously, `WARN_ONCE` was always triggered. Now, if `kernel_set_to_readonly` is false, it logs a `pr_warn_once` message. The key is when is this `kernel_set_to_readonly` flag false? Ah, right – `kernel_set_to_readonly` is zero during boot, before `mark_rodata_ro()` is called. This is important: it's also zero when the kernel is booted with `rodata=off`. Syzkaller might boot with `rodata=off`, which means this new branch could be frequently taken during fuzzing. CPA (Change Page Attribute) is called at runtime when modules are loaded/unloaded, BPF JIT allocates/frees executable memory, and set_memory_ro/rw/x/nx/uc/wb is called via various drivers and subsystems. This suggests the code is absolutely reachable. To be certain, I'm going to quickly check who calls CPA functions at runtime. I need to grep the kernel for callers of `change_page_attr` or `set_memory_` to confirm reachability. Based on this, my preliminary evaluation is yes, this patch does warrant fuzzing. The change introduces a new code path that's likely reachable, especially with `rodata=off`, and involves a potentially important change in behavior. This definitely has the potential to expose latent bugs or trigger new assertions, so I would flag this for the fuzzing queue.
18/2	2026/09/11 12:38	tool	grepper	0m Args: { "Expression": "set_memory_", "PathPrefix": "arch/x86/" } Results: { "Output": "\nFull output is too long, showing 500 out of 761 lines.\nUse more precise expression if possible.\n\narch/x86/boot/startup/exports.h=6=PROVIDE(early_set_pages_state\t\t= __pi_early_set_pages_state);\narch/x86/boot/startup/exports.h:7:PROVIDE(early_snp_set_memory_private\t= __pi_early_snp_set_memory_private);\narch/x86/boot/startup/exports.h:8:PROVIDE(early_snp_set_memory_shared\t= __pi_early_snp_set_memory_shared);\narch/x86/boot/startup/exports.h-9-PROVIDE(get_hv_features\t\t\t= __pi_get_hv_features);\n--\narch/x86/boot/startup/map_kernel.c=33=static unsigned long __init sme_postprocess_startup(struct boot_params bp,\n--\narch/x86/boot/startup/map_kernel.c-59-\t\t\t mapping (kernel .text). PVALIDATE, by way of\narch/x86/boot/startup/map_kernel.c:60:\t\t\t * early_snp_set_memory_shared(), requires a valid virtual\narch/x86/boot/startup/map_kernel.c-61-\t\t\t * address but the kernel is currently running off of the identity\n--\narch/x86/boot/startup/map_kernel.c-63-\t\t\t /\narch/x86/boot/startup/map_kernel.c:64:\t\t\tearly_snp_set_memory_shared(paddr, paddr, PTRS_PER_PMD);\narch/x86/boot/startup/map_kernel.c-65-\n--\narch/x86/boot/startup/sev-startup.c=49=early_set_pages_state(unsigned long vaddr, unsigned long paddr,\n--\narch/x86/boot/startup/sev-startup.c-66-\narch/x86/boot/startup/sev-startup.c:67:void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,\narch/x86/boot/startup/sev-startup.c-68-\t\t\t\t\t unsigned long npages)\n--\narch/x86/boot/startup/sev-startup.c-91-\narch/x86/boot/startup/sev-startup.c:92:void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,\narch/x86/boot/startup/sev-startup.c-93-\t\t\t\t\tunsigned long npages)\n--\narch/x86/coco/sev/core.c=387=static void set_pages_state(unsigned long vaddr, unsigned long npages, int op)\n--\narch/x86/coco/sev/core.c-405-\narch/x86/coco/sev/core.c:406:void snp_set_memory_shared(unsigned long vaddr, unsigned long npages)\narch/x86/coco/sev/core.c-407-{\n--\narch/x86/coco/sev/core.c-413-\narch/x86/coco/sev/core.c:414:void snp_set_memory_private(unsigned long vaddr, unsigned long npages)\narch/x86/coco/sev/core.c-415-{\n--\narch/x86/coco/sev/core.c=544=static void unshare_all_memory(void)\n--\narch/x86/coco/sev/core.c-585-\t\t\tset_pte_enc(pte, level, (void )addr);\narch/x86/coco/sev/core.c:586:\t\t\tsnp_set_memory_private(addr, npages);\narch/x86/coco/sev/core.c-587-\t\t}\n--\narch/x86/coco/sev/core.c-603-\taddr = (unsigned long)__start_bss_decrypted;\narch/x86/coco/sev/core.c:604:\tsnp_set_memory_private(addr, npages);\narch/x86/coco/sev/core.c-605-\n--\narch/x86/coco/sev/core.c=610=void snp_kexec_begin(void)\n--\narch/x86/coco/sev/core.c-623-\t /\narch/x86/coco/sev/core.c:624:\tif (!set_memory_enc_stop_conversion())\narch/x86/coco/sev/core.c-625-\t\tpr_warn(\"Failed to stop shared\u003c-\u003eprivate conversions\\n\");\n--\narch/x86/coco/sev/core.c=687=void snp_kexec_finish(void)\n--\narch/x86/coco/sev/core.c-721-\t\tset_pte_enc(pte, level, (void )addr);\narch/x86/coco/sev/core.c:722:\t\tsnp_set_memory_private(addr, (size / PAGE_SIZE));\narch/x86/coco/sev/core.c-723-\t}\n--\narch/x86/coco/sev/core.c=1208=static void __init init_ghcb(int cpu)\n--\narch/x86/coco/sev/core.c-1214-\narch/x86/coco/sev/core.c:1215:\terr = early_set_memory_decrypted((unsigned long)\u0026data-\u003eghcb_page,\narch/x86/coco/sev/core.c-1216-\t\t\t\t\t sizeof(data-\u003eghcb_page));\n--\narch/x86/coco/sev/core.c=1473=static void free_shared_pages(void buf, size_t sz)\n--\narch/x86/coco/sev/core.c-1480-\narch/x86/coco/sev/core.c:1481:\tret = set_memory_encrypted((unsigned long)buf, npages);\narch/x86/coco/sev/core.c-1482-\tif (ret) {\n--\narch/x86/coco/sev/core.c=1490=static void alloc_shared_pages(size_t sz)\n--\narch/x86/coco/sev/core.c-1499-\narch/x86/coco/sev/core.c:1500:\tret = set_memory_decrypted((unsigned long)page_address(page), npages);\narch/x86/coco/sev/core.c-1501-\tif (ret) {\n--\narch/x86/coco/tdx/tdx.c=1010=static void tdx_kexec_begin(void)\n--\narch/x86/coco/tdx/tdx.c-1020-\t /\narch/x86/coco/tdx/tdx.c:1021:\tif (!set_memory_enc_stop_conversion())\narch/x86/coco/tdx/tdx.c-1022-\t\tpr_warn(\"Failed to stop shared\u003c-\u003eprivate conversions\\n\");\n--\narch/x86/hyperv/hv_init.c=118=static int hv_cpu_init(unsigned int cpu)\n--\narch/x86/hyperv/hv_init.c-158-\t\t\tif (hvp \u0026\u0026 !ms_hyperv.paravisor_present \u0026\u0026 hv_isolation_type_snp()) {\narch/x86/hyperv/hv_init.c:159:\t\t\t\tWARN_ON_ONCE(set_memory_decrypted((unsigned long)(hvp), 1));\narch/x86/hyperv/hv_init.c-160-\t\t\t\tmemset(hvp, 0, PAGE_SIZE);\n--\narch/x86/hyperv/ivm.c=617=static void hv_vtom_kexec_begin(void)\n--\narch/x86/hyperv/ivm.c-627-\t /\narch/x86/hyperv/ivm.c:628:\tif (!set_memory_enc_stop_conversion())\narch/x86/hyperv/ivm.c-629-\t\tpr_warn(\"Failed to stop shared\u003c-\u003eprivate conversions\\n\");\n--\narch/x86/hyperv/ivm.c=677=static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],\n--\narch/x86/hyperv/ivm.c-737- When transitioning memory between encrypted and decrypted, the caller\narch/x86/hyperv/ivm.c:738: * of set_memory_encrypted() or set_memory_decrypted() is responsible for\narch/x86/hyperv/ivm.c-739- * ensuring that the memory isn't in use and isn't referenced while the\n--\narch/x86/hyperv/ivm.c=756=static int hv_vtom_clear_present(unsigned long kbuffer, int pagecount, bool enc)\narch/x86/hyperv/ivm.c-757-{\narch/x86/hyperv/ivm.c:758:\treturn set_memory_np(kbuffer, pagecount);\narch/x86/hyperv/ivm.c-759-}\n--\narch/x86/hyperv/ivm.c=769=static int hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)\n--\narch/x86/hyperv/ivm.c-781-\t\tret = -ENOMEM;\narch/x86/hyperv/ivm.c:782:\t\tgoto err_set_memory_p;\narch/x86/hyperv/ivm.c-783-\t}\n--\narch/x86/hyperv/ivm.c-808-\narch/x86/hyperv/ivm.c:809:err_set_memory_p:\narch/x86/hyperv/ivm.c-810-\t/\n--\narch/x86/hyperv/ivm.c-815-\t /\narch/x86/hyperv/ivm.c:816:\terr = set_memory_p(kbuffer, pagecount);\narch/x86/hyperv/ivm.c-817-\tif (err \u0026\u0026 !ret)\n--\narch/x86/include/asm/efi.h=238=static inline u32 efi64_convert_status(efi_status_t status)\n--\narch/x86/include/asm/efi.h-298-\narch/x86/include/asm/efi.h:299:#define __efi64_argmap_set_memory_space_attributes(phys, size, flags) \\\narch/x86/include/asm/efi.h-300-\t(__efi64_split(phys), __efi64_split(size), __efi64_split(flags))\n--\narch/x86/include/asm/efi.h-316-\narch/x86/include/asm/efi.h:317:#define __efi64_argmap_set_memory_attributes(protocol, phys, size, flags) \\\narch/x86/include/asm/efi.h-318-\t((protocol), __efi64_split(phys), __efi64_split(size), __efi64_split(flags))\n--\narch/x86/include/asm/kfence.h=22=static inline bool arch_kfence_init_pool(void)\n--\narch/x86/include/asm/kfence.h-33-\t\tif (level != PG_LEVEL_4K)\narch/x86/include/asm/kfence.h:34:\t\t\tset_memory_4k(addr, 1);\narch/x86/include/asm/kfence.h-35-\t}\n--\narch/x86/include/asm/mem_encrypt.h=51=void sme_enable(struct boot_params bp);\narch/x86/include/asm/mem_encrypt.h-52-\narch/x86/include/asm/mem_encrypt.h:53:int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size);\narch/x86/include/asm/mem_encrypt.h:54:int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size);\narch/x86/include/asm/mem_encrypt.h-55-void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr,\n--\narch/x86/include/asm/mem_encrypt.h=89=static inline int __init\narch/x86/include/asm/mem_encrypt.h:90:early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; }\narch/x86/include/asm/mem_encrypt.h-91-static inline int __init\narch/x86/include/asm/mem_encrypt.h:92:early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0; }\narch/x86/include/asm/mem_encrypt.h-93-static inline void __init\n--\narch/x86/include/asm/set_memory.h-8-\narch/x86/include/asm/set_memory.h:9:#define set_memory_rox set_memory_rox\narch/x86/include/asm/set_memory.h:10:int set_memory_rox(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h-11-\narch/x86/include/asm/set_memory.h-12-/\narch/x86/include/asm/set_memory.h:13: * The set_memory_* API can be used to change various attributes of a virtual\narch/x86/include/asm/set_memory.h-14- * address range. The attributes include:\n--\narch/x86/include/asm/set_memory.h-40-\narch/x86/include/asm/set_memory.h:41:int _set_memory_uc(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:42:int _set_memory_wc(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:43:int _set_memory_wt(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:44:int _set_memory_wb(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:45:int set_memory_uc(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:46:int set_memory_wc(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:47:int set_memory_wb(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:48:int set_memory_np(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:49:int set_memory_p(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:50:int set_memory_4k(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h-51-\narch/x86/include/asm/set_memory.h:52:bool set_memory_enc_stop_conversion(void);\narch/x86/include/asm/set_memory.h:53:int set_memory_encrypted(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:54:int set_memory_decrypted(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h-55-\narch/x86/include/asm/set_memory.h:56:int set_memory_np_noalias(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:57:int set_memory_nonglobal(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:58:int set_memory_global(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h-59-\n--\narch/x86/include/asm/set_memory.h=62=int set_pages_array_wb(struct page *pages, int addrinarray);\n--\narch/x86/include/asm/set_memory.h-68- memory that the struct page represents, and internally just\narch/x86/include/asm/set_memory.h:69: * call the set_memory_* function. See the description of the\narch/x86/include/asm/set_memory.h:70: * set_memory_* function for more details on conventions.\narch/x86/include/asm/set_memory.h-71- \n--\narch/x86/include/asm/set_memory.h-79- get a struct page* that the old API required.\narch/x86/include/asm/set_memory.h:80: * To convert these cases, use set_memory_() on the original\narch/x86/include/asm/set_memory.h-81- virtual address, do not use these functions.\n--\narch/x86/include/asm/sev.h=505=void snp_register_ghcb_early(unsigned long paddr);\narch/x86/include/asm/sev.h:506:void early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,\narch/x86/include/asm/sev.h-507-\t\t\t\t unsigned long npages);\narch/x86/include/asm/sev.h:508:void early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,\narch/x86/include/asm/sev.h-509-\t\t\t\t unsigned long npages);\narch/x86/include/asm/sev.h:510:void snp_set_memory_shared(unsigned long vaddr, unsigned long npages);\narch/x86/include/asm/sev.h:511:void snp_set_memory_private(unsigned long vaddr, unsigned long npages);\narch/x86/include/asm/sev.h-512-void snp_set_wakeup_secondary_cpu(void);\n--\narch/x86/include/asm/sev.h=612=static inline void __init\narch/x86/include/asm/sev.h:613:early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, unsigned long npages) { }\narch/x86/include/asm/sev.h-614-static inline void __init\narch/x86/include/asm/sev.h:615:early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, unsigned long npages) { }\narch/x86/include/asm/sev.h:616:static inline void snp_set_memory_shared(unsigned long vaddr, unsigned long npages) { }\narch/x86/include/asm/sev.h:617:static inline void snp_set_memory_private(unsigned long vaddr, unsigned long npages) { }\narch/x86/include/asm/sev.h-618-static inline void snp_set_wakeup_secondary_cpu(void) { }\n--\narch/x86/include/asm/vga.h-24-\tif (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))\t\t\t\\\narch/x86/include/asm/vga.h:25:\t\tset_memory_decrypted(start, (s) \u003e\u003e PAGE_SHIFT);\t\\\narch/x86/include/asm/vga.h-26-\t\t\t\t\t\t\t\t\\\n--\narch/x86/kernel/alternative.c=218=static void its_alloc(void)\n--\narch/x86/kernel/alternative.c-232-\tif (pages == \u0026its_pages)\narch/x86/kernel/alternative.c:233:\t\tset_memory_x((unsigned long)page, 1);\narch/x86/kernel/alternative.c-234-\n--\narch/x86/kernel/amd_gart_64.c=619=static __init int init_amd_gatt(struct agp_kern_info info)\n--\narch/x86/kernel/amd_gart_64.c-654-\t\tpanic(\"Cannot allocate GATT table\");\narch/x86/kernel/amd_gart_64.c:655:\tif (set_memory_uc((unsigned long)gatt, gatt_size \u003e\u003e PAGE_SHIFT))\narch/x86/kernel/amd_gart_64.c-656-\t\tpanic(\"Could not set GART PTEs to uncacheable pages\");\n--\narch/x86/kernel/amd_gart_64.c=714=int __init gart_iommu_init(void)\n--\narch/x86/kernel/amd_gart_64.c-781-\t /\narch/x86/kernel/amd_gart_64.c:782:\tset_memory_np((unsigned long)__va(iommu_bus_base),\narch/x86/kernel/amd_gart_64.c-783-\t\t\t\tiommu_size \u003e\u003e PAGE_SHIFT);\n--\narch/x86/kernel/apic/x2apic_uv_x.c=559=static __init void set_block_size(void)\n--\narch/x86/kernel/apic/x2apic_uv_x.c-564-\t\t/ adjust for ffs return of 1..64 /\narch/x86/kernel/apic/x2apic_uv_x.c:565:\t\tset_memory_block_size_order(order - 1);\narch/x86/kernel/apic/x2apic_uv_x.c-566-\t\tpr_info(\"UV: mem_block_size set to 0x%lx\\n\", mem_block_size);\n--\narch/x86/kernel/apic/x2apic_uv_x.c-569-\t\tpr_err(\"UV: mem_block_size error with 0x%lx\\n\", mem_block_size);\narch/x86/kernel/apic/x2apic_uv_x.c:570:\t\tset_memory_block_size_order(31);\narch/x86/kernel/apic/x2apic_uv_x.c-571-\t}\n--\narch/x86/kernel/cpu/common.c=2588=void __init arch_cpu_finalize_init(void)\n--\narch/x86/kernel/cpu/common.c-2663-\t\tif (!direct_gbpages)\narch/x86/kernel/cpu/common.c:2664:\t\t\tset_memory_4k((unsigned long)__va(0), 1);\narch/x86/kernel/cpu/common.c-2665-\t} else {\n--\narch/x86/kernel/ftrace.c=309=create_trampoline(struct ftrace_ops ops, unsigned int tramp_size)\n--\narch/x86/kernel/ftrace.c-427-\narch/x86/kernel/ftrace.c:428:\tset_memory_rox((unsigned long)trampoline, npages);\narch/x86/kernel/ftrace.c-429-\treturn (unsigned long)trampoline;\n--\narch/x86/kernel/ftrace.c=435=void set_ftrace_ops_ro(void)\n--\narch/x86/kernel/ftrace.c-456-\t\tnpages = DIV_ROUND_UP(size, PAGE_SIZE);\narch/x86/kernel/ftrace.c:457:\t\tset_memory_ro((unsigned long)ops-\u003etrampoline, npages);\narch/x86/kernel/ftrace.c-458-\t} while_for_each_ftrace_op(ops);\n--\narch/x86/kernel/idt.c=294=void __init idt_setup_apic_and_irq_gates(void)\n--\narch/x86/kernel/idt.c-321-\t/ Make the IDT table read only /\narch/x86/kernel/idt.c:322:\tset_memory_ro((unsigned long)\u0026idt_table, 1);\narch/x86/kernel/idt.c-323-\n--\narch/x86/kernel/kvm.c=432=static inline __init void __set_percpu_decrypted(void ptr, unsigned long size)\narch/x86/kernel/kvm.c-433-{\narch/x86/kernel/kvm.c:434:\tearly_set_memory_decrypted((unsigned long) ptr, size);\narch/x86/kernel/kvm.c-435-}\n--\narch/x86/kernel/kvmclock.c=225=static void __init kvmclock_init_mem(void)\n--\narch/x86/kernel/kvmclock.c-250-\tif (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {\narch/x86/kernel/kvmclock.c:251:\t\tr = set_memory_decrypted((unsigned long) hvclock_mem,\narch/x86/kernel/kvmclock.c-252-\t\t\t\t\t 1UL \u003c\u003c order);\n--\narch/x86/kernel/kvmclock.c-255-\t\t\thvclock_mem = NULL;\narch/x86/kernel/kvmclock.c:256:\t\t\tpr_warn(\"kvmclock: set_memory_decrypted() failed. Disabling\\n\");\narch/x86/kernel/kvmclock.c-257-\t\t\treturn;\n--\narch/x86/kernel/machine_kexec_32.c=135=int machine_kexec_prepare(struct kimage image)\n--\narch/x86/kernel/machine_kexec_32.c-138-\narch/x86/kernel/machine_kexec_32.c:139:\tset_memory_x((unsigned long)page_address(image-\u003econtrol_code_page), 1);\narch/x86/kernel/machine_kexec_32.c-140-\terror = machine_kexec_alloc_page_tables(image);\n--\narch/x86/kernel/machine_kexec_32.c=151=void machine_kexec_cleanup(struct kimage image)\narch/x86/kernel/machine_kexec_32.c-152-{\narch/x86/kernel/machine_kexec_32.c:153:\tset_memory_nx((unsigned long)page_address(image-\u003econtrol_code_page), 1);\narch/x86/kernel/machine_kexec_32.c-154-\tmachine_kexec_free_page_tables(image);\n--\narch/x86/kernel/machine_kexec_64.c=343=int machine_kexec_prepare(struct kimage image)\n--\narch/x86/kernel/machine_kexec_64.c-364-\narch/x86/kernel/machine_kexec_64.c:365:\tset_memory_rox((unsigned long)control_page, 1);\narch/x86/kernel/machine_kexec_64.c-366-\n--\narch/x86/kernel/machine_kexec_64.c=370=void machine_kexec_cleanup(struct kimage image)\n--\narch/x86/kernel/machine_kexec_64.c-373-\narch/x86/kernel/machine_kexec_64.c:374:\tset_memory_nx((unsigned long)control_page, 1);\narch/x86/kernel/machine_kexec_64.c:375:\tset_memory_rw((unsigned long)control_page, 1);\narch/x86/kernel/machine_kexec_64.c-376-\n--\narch/x86/kernel/machine_kexec_64.c=648=static void kexec_mark_dm_crypt_keys(bool protect)\n--\narch/x86/kernel/machine_kexec_64.c-657-\t\tif (protect)\narch/x86/kernel/machine_kexec_64.c:658:\t\t\tset_memory_np((unsigned long)phys_to_virt(start_paddr), nr_pages);\narch/x86/kernel/machine_kexec_64.c-659-\t\telse\narch/x86/kernel/machine_kexec_64.c:660:\t\t\tset_memory_p((unsigned long)phys_to_virt(start_paddr), nr_pages);\narch/x86/kernel/machine_kexec_64.c-661-\t}\n--\narch/x86/kernel/machine_kexec_64.c=686=int arch_kexec_post_alloc_pages(void vaddr, unsigned int pages, gfp_t gfp)\n--\narch/x86/kernel/machine_kexec_64.c-695-\t /\narch/x86/kernel/machine_kexec_64.c:696:\treturn set_memory_decrypted((unsigned long)vaddr, pages);\narch/x86/kernel/machine_kexec_64.c-697-}\n--\narch/x86/kernel/machine_kexec_64.c=699=void arch_kexec_pre_free_pages(void vaddr, unsigned int pages)\n--\narch/x86/kernel/machine_kexec_64.c-707-\t /\narch/x86/kernel/machine_kexec_64.c:708:\tset_memory_encrypted((unsigned long)vaddr, pages);\narch/x86/kernel/machine_kexec_64.c-709-}\n--\narch/x86/kvm/lapic.c=2910=int kvm_alloc_apic_access_page(struct kvm kvm)\n--\narch/x86/kvm/lapic.c-2919-\narch/x86/kvm/lapic.c:2920:\thva = __x86_set_memory_region(kvm, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,\narch/x86/kvm/lapic.c-2921-\t\t\t\t APIC_DEFAULT_PHYS_BASE, PAGE_SIZE);\n--\narch/x86/kvm/lapic.c=2931=void kvm_inhibit_apic_access_page(struct kvm_vcpu vcpu)\n--\narch/x86/kvm/lapic.c-2942-\tif (kvm-\u003earch.apic_access_memslot_enabled) {\narch/x86/kvm/lapic.c:2943:\t\t__x86_set_memory_region(kvm, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT, 0, 0);\narch/x86/kvm/lapic.c-2944-\t\t/\n--\narch/x86/kvm/mmu/mmu.c=6801=static void free_mmu_pages(struct kvm_mmu mmu)\n--\narch/x86/kvm/mmu/mmu.c-6803-\tif (!tdp_enabled \u0026\u0026 mmu-\u003epae_root)\narch/x86/kvm/mmu/mmu.c:6804:\t\tset_memory_encrypted((unsigned long)mmu-\u003epae_root, 1);\narch/x86/kvm/mmu/mmu.c-6805-\tfree_page((unsigned long)mmu-\u003epae_root);\n--\narch/x86/kvm/mmu/mmu.c=6810=static int __kvm_mmu_create(struct kvm_vcpu vcpu, struct kvm_mmu mmu, struct kvm_pagewalk w)\n--\narch/x86/kvm/mmu/mmu.c-6854-\tif (!tdp_enabled)\narch/x86/kvm/mmu/mmu.c:6855:\t\tset_memory_decrypted((unsigned long)mmu-\u003epae_root, 1);\narch/x86/kvm/mmu/mmu.c-6856-\telse\n--\narch/x86/kvm/mmu/mmu.c=8113=static void hugepage_set_mixed(struct kvm_memory_slot slot, gfn_t gfn,\n--\narch/x86/kvm/mmu/mmu.c-8118-\narch/x86/kvm/mmu/mmu.c:8119:bool kvm_arch_pre_set_memory_attributes(struct kvm kvm,\narch/x86/kvm/mmu/mmu.c-8120-\t\t\t\t\tstruct kvm_gfn_range range)\n--\narch/x86/kvm/mmu/mmu.c=8182=static bool hugepage_has_attrs(struct kvm kvm, struct kvm_memory_slot slot,\n--\narch/x86/kvm/mmu/mmu.c-8198-\narch/x86/kvm/mmu/mmu.c:8199:bool kvm_arch_post_set_memory_attributes(struct kvm kvm,\narch/x86/kvm/mmu/mmu.c-8200-\t\t\t\t\t struct kvm_gfn_range range)\n--\narch/x86/kvm/vmx/vmx.c=4029=static int init_rmode_identity_map(struct kvm kvm)\n--\narch/x86/kvm/vmx/vmx.c-4044-\narch/x86/kvm/vmx/vmx.c:4045:\tuaddr = __x86_set_memory_region(kvm,\narch/x86/kvm/vmx/vmx.c-4046-\t\t\t\t\tIDENTITY_PAGETABLE_PRIVATE_MEMSLOT,\n--\narch/x86/kvm/vmx/vmx.c=5276=int vmx_set_tss_addr(struct kvm kvm, unsigned int addr)\n--\narch/x86/kvm/vmx/vmx.c-5283-\tmutex_lock(\u0026kvm-\u003eslots_lock);\narch/x86/kvm/vmx/vmx.c:5284:\tret = __x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, addr,\narch/x86/kvm/vmx/vmx.c-5285-\t\t\t\t PAGE_SIZE * 3);\n--\narch/x86/kvm/x86.c=9843=int kvm_arch_init_vm(struct kvm kvm, unsigned long type)\n--\narch/x86/kvm/x86.c-9916-/\narch/x86/kvm/x86.c:9917: __x86_set_memory_region: Setup KVM internal memory slot\narch/x86/kvm/x86.c-9918- \n--\narch/x86/kvm/x86.c-9937- /\narch/x86/kvm/x86.c:9938:void __user * __x86_set_memory_region(struct kvm kvm, int id, gpa_t gpa,\narch/x86/kvm/x86.c-9939-\t\t\t\t u32 size)\n--\narch/x86/kvm/x86.c-9989-}\narch/x86/kvm/x86.c:9990:EXPORT_SYMBOL_FOR_KVM_INTERNAL(__x86_set_memory_region);\narch/x86/kvm/x86.c-9991-\n--\narch/x86/kvm/x86.c=10014=void kvm_arch_destroy_vm(struct kvm kvm)\n--\narch/x86/kvm/x86.c-10022-\t\tmutex_lock(\u0026kvm-\u003eslots_lock);\narch/x86/kvm/x86.c:10023:\t\t__x86_set_memory_region(kvm, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,\narch/x86/kvm/x86.c-10024-\t\t\t\t\t0, 0);\narch/x86/kvm/x86.c:10025:\t\t__x86_set_memory_region(kvm, IDENTITY_PAGETABLE_PRIVATE_MEMSLOT,\narch/x86/kvm/x86.c-10026-\t\t\t\t\t0, 0);\narch/x86/kvm/x86.c:10027:\t\t__x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, 0, 0);\narch/x86/kvm/x86.c-10028-\t\tmutex_unlock(\u0026kvm-\u003eslots_lock);\n--\narch/x86/kvm/x86.c=10093=static int kvm_alloc_memslot_metadata(struct kvm kvm,\n--\narch/x86/kvm/x86.c-10100-\t Clear out the previous array pointers for the KVM_MR_MOVE case. The\narch/x86/kvm/x86.c:10101:\t * old arrays will be freed by kvm_set_memory_region() if installing\narch/x86/kvm/x86.c-10102-\t * the new memslot is successful.\n--\narch/x86/kvm/x86.h=526=int kvm_get_nr_pending_nmis(struct kvm_vcpu vcpu);\narch/x86/kvm/x86.h-527-\narch/x86/kvm/x86.h:528:void __user __x86_set_memory_region(struct kvm kvm, int id, gpa_t gpa,\narch/x86/kvm/x86.h-529-\t\t\t\t u32 size);\n--\narch/x86/mm/init.c=897=void free_init_pages(const char what, unsigned long begin, unsigned long end)\n--\narch/x86/mm/init.c-925-\t\tkmemleak_free_part((void )begin, end - begin);\narch/x86/mm/init.c:926:\t\tset_memory_np(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c-927-\t} else {\n--\narch/x86/mm/init.c-932-\t\t /\narch/x86/mm/init.c:933:\t\tset_memory_nx(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c:934:\t\tset_memory_rw(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c-935-\n--\narch/x86/mm/init.c=946=void free_kernel_image_pages(const char what, void begin, void end)\n--\narch/x86/mm/init.c-969-\tif (IS_ENABLED(CONFIG_X86_64) \u0026\u0026 cpu_feature_enabled(X86_FEATURE_PTI))\narch/x86/mm/init.c:970:\t\tset_memory_np_noalias(begin_ul, len_pages);\narch/x86/mm/init.c-971-}\n--\narch/x86/mm/init_32.c=723=static void mark_nxdata_nx(void)\n--\narch/x86/mm/init_32.c-736-\t\tprintk(KERN_INFO \"NX-protecting the kernel data: %luk\\n\", size \u003e\u003e 10);\narch/x86/mm/init_32.c:737:\tset_memory_nx(start, size \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_32.c-738-}\n--\narch/x86/mm/init_64.c=1359=void mark_rodata_ro(void)\n--\narch/x86/mm/init_64.c-1369-\t (end - start) \u003e\u003e 10);\narch/x86/mm/init_64.c:1370:\tset_memory_ro(start, (end - start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1371-\n--\narch/x86/mm/init_64.c-1386-\tall_end = roundup((unsigned long)_brk_end, PMD_SIZE);\narch/x86/mm/init_64.c:1387:\tset_memory_nx(text_end, (all_end - text_end) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1388-\n--\narch/x86/mm/init_64.c-1392-\tprintk(KERN_INFO \"Testing CPA: undo %lx-%lx\\n\", start, end);\narch/x86/mm/init_64.c:1393:\tset_memory_rw(start, (end-start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1394-\narch/x86/mm/init_64.c-1395-\tprintk(KERN_INFO \"Testing CPA: again\\n\");\narch/x86/mm/init_64.c:1396:\tset_memory_ro(start, (end-start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1397-#endif\n--\narch/x86/mm/init_64.c-1415-/ Adjustable memory block size /\narch/x86/mm/init_64.c:1416:static unsigned long set_memory_block_size;\narch/x86/mm/init_64.c:1417:int __init set_memory_block_size_order(unsigned int order)\narch/x86/mm/init_64.c-1418-{\n--\narch/x86/mm/init_64.c-1423-\narch/x86/mm/init_64.c:1424:\tset_memory_block_size = size;\narch/x86/mm/init_64.c-1425-\treturn 0;\n--\narch/x86/mm/init_64.c=1428=static unsigned long probe_memory_block_size(void)\n--\narch/x86/mm/init_64.c-1433-\t/ If memory block size has been set, then use it /\narch/x86/mm/init_64.c:1434:\tbz = set_memory_block_size;\narch/x86/mm/init_64.c-1435-\tif (bz)\n--\narch/x86/mm/ioremap.c=45=int ioremap_change_attr(unsigned long vaddr, unsigned long size,\n--\narch/x86/mm/ioremap.c-53-\tdefault:\narch/x86/mm/ioremap.c:54:\t\terr = _set_memory_uc(vaddr, nrpages);\narch/x86/mm/ioremap.c-55-\t\tbreak;\narch/x86/mm/ioremap.c-56-\tcase _PAGE_CACHE_MODE_WC:\narch/x86/mm/ioremap.c:57:\t\terr = _set_memory_wc(vaddr, nrpages);\narch/x86/mm/ioremap.c-58-\t\tbreak;\narch/x86/mm/ioremap.c-59-\tcase _PAGE_CACHE_MODE_WT:\narch/x86/mm/ioremap.c:60:\t\terr = _set_memory_wt(vaddr, nrpages);\narch/x86/mm/ioremap.c-61-\t\tbreak;\narch/x86/mm/ioremap.c-62-\tcase _PAGE_CACHE_MODE_WB:\narch/x86/mm/ioremap.c:63:\t\terr = _set_memory_wb(vaddr, nrpages);\narch/x86/mm/ioremap.c-64-\t\tbreak;\n--\narch/x86/mm/mem_encrypt_amd.c=57=static inline void __init snp_memcpy(void dst, void src, size_t sz,\n--\narch/x86/mm/mem_encrypt_amd.c-66-\t\t /\narch/x86/mm/mem_encrypt_amd.c:67:\t\tearly_snp_set_memory_shared((unsigned long)__va(paddr), paddr, npages);\narch/x86/mm/mem_encrypt_amd.c-68-\n--\narch/x86/mm/mem_encrypt_amd.c-71-\t\t/* Restore the page state after the memcpy. /\narch/x86/mm/mem_encrypt_amd.c:72:\t\tearly_snp_set_memory_private((unsigned long)__va(paddr), paddr, npages);\narch/x86/mm/mem_encrypt_amd.c-73-\t} else {\n--\narch/x86/mm/mem_encrypt_amd.c=286=static int amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-292-\tif (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) \u0026\u0026 !enc)\narch/x86/mm/mem_encrypt_amd.c:293:\t\tsnp_set_memory_shared(vaddr, npages);\narch/x86/mm/mem_encrypt_amd.c-294-\n--\narch/x86/mm/mem_encrypt_amd.c=299=static int amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-305-\tif (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) \u0026\u0026 enc)\narch/x86/mm/mem_encrypt_amd.c:306:\t\tsnp_set_memory_private(vaddr, npages);\narch/x86/mm/mem_encrypt_amd.c-307-\n--\narch/x86/mm/mem_encrypt_amd.c=358=static void __init __set_clr_pte_enc(pte_t kpte, int level, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-378-\t\t */\narch/x86/mm/mem_encrypt_amd.c:379:\t\tearly_snp_set_memory_shared((unsigned long)__va(d.pa), d.pa, 1);\narch/x86/mm/mem_encrypt_amd.c-380-\t}\n--\narch/x86/mm/mem_encrypt_amd.c-388-\tif (enc)\n\n" }
19/2	2026/09/11 12:38	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 28343 output: 21 thoughts: 1378 Thoughts: Analyzing W^X Violation Detection in set_memory.c Alright, let's break this down. My initial thought process is to understand the context of this `set_memory.c` file and, specifically, the functions like `set_memory_ro`, `set_memory_rw`, and others. Where are these functions called? I need to build a mental map of their usage. I recall BPF JIT, ftrace, the module loader – they all manipulate memory permissions. My mind immediately jumps to the relevant functions: `module_enable_ro()`, `module_enable_nx()`, `bpf_jit_binary_lock_ro()`, and `bpf_prog_lock_ro()`. Kprobes also come to mind with `alloc_insn_page()` and its implications on setting read-only/read-write permissions. Let's not forget `/dev/mem` and `ioremap` which could be relevant too. I need to keep these in mind as potential call sites. Now, to get into the nitty-gritty of the patch itself, I should examine the `git show` output to understand the changes. Let's see... the code introduces a warning about W^X violations within the `verify_rwx` function. I see the addition of a `pr_warn_once` call. I carefully examine the `verify_rwx` function. It seems to check for changes that could violate the Write XOR Execute (W^X) principle. It has some conditions related to the architecture (32-bit specifically) and NX support. I can see the core logic of the W^X check, looking at the old and new page protection flags. Aha! Now I see a crucial detail: there are two `pr_warn_once` calls in the code. One is conditional on `!kernel_set_to_readonly` and the other is unconditional. My attention is now drawn to the first argument of `pr_warn_once`. Is it a condition, or is it part of the format string? That's a classic gotcha! I need to be absolutely sure what that first argument is doing. Let's check the definition of `pr_warn_once`! I need to be certain about the logging behavior here.
20/2	2026/09/11 12:38	tool	grepper	0m Args: { "Expression": "#define pr_warn_once" } Results: { "Output": "include/linux/ceph/ceph_debug.h-59-\t\tclient-\u003emonc.auth-\u003eglobal_id, ##__VA_ARGS__)\ninclude/linux/ceph/ceph_debug.h:60:#define pr_warn_once_client(client, fmt, ...)\t\t\t\t\\\ninclude/linux/ceph/ceph_debug.h-61-\tpr_warn_once(\"[%pU %llu]: \" fmt, \u0026client-\u003efsid,\t\t\t\\\n--\ninclude/linux/printk.h=407=struct pi_entry {\n--\ninclude/linux/printk.h-667-\tprintk_once(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)\ninclude/linux/printk.h:668:#define pr_warn_once(fmt, ...)\t\t\t\t\t\\\ninclude/linux/printk.h-669-\tprintk_once(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)\n--\nsecurity/selinux/ss/policydb.h=417=extern u32 string_to_av_perm(struct policydb p, u16 tclass, const char name);\nsecurity/selinux/ss/policydb.h-418-\nsecurity/selinux/ss/policydb.h:419:#define pr_warn_once_policyload(policy, fmt, ...) \\\nsecurity/selinux/ss/policydb.h-420-\tdo { \\\n--\ntools/testing/vma/include/custom.h=12=extern unsigned long dac_mmap_min_addr;\n--\ntools/testing/vma/include/custom.h-23- */\ntools/testing/vma/include/custom.h:24:#define pr_warn_once pr_err\ntools/testing/vma/include/custom.h-25-\n" }
21/2	2026/09/11 12:38	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 30692 output: 38 thoughts: 803 Thoughts: Kernel Bug Discovery: A Deep Dive Okay, here's what's going through my head as I analyze this: I'm staring at this `pr_warn_once(1, "CPA detected...")` and something instantly screams "wrong!" The function signature clearly indicates the first parameter should be the format string, not a numerical value. My immediate thought is, "Wait, `pr_warn_once(fmt, ...)` takes `fmt` first!", then I cross-reference this with `WARN_ONCE(condition, fmt, ...)` which takes the condition first. It's like deja vu. In this specific patch, it's calling `pr_warn_once(1, "CPA detected W^X violation: %016llx -> ...", ...)` and the first argument is just the number `1` which is being interpreted as a pointer, specifically `(const char )1`, or, essentially, NULL plus one! This is when the alarm bells go off. When `pr_warn_once(1, ...)` is invoked, `fmt` is being set to `(char )1`. That means, ultimately, we're trying to dereference the address `0x00000001`! This is going to cause a kernel oops, a page fault, because it's accessing an invalid memory location! HOLY COW, that's a serious bug! The author appears to have copied `WARN_ONCE(1, "...")` and simply changed `WARN_ONCE` to `pr_warn_once`, without removing the conditional `1`! They're passing `1` as a format string when it should be `"CPA detected..."`. Essentially, if `!kernel_set_to_readonly` and `verify_rwx` detects a W^X violation, calling `pr_warn_once(1, ...)` passes integer 1 as pointer to format string into `printk_once` -> `vprintk_store` -> page fault! This is going to crash the kernel in the worst way. Now I need to understand how reachable this actually is. When does `verify_rwx` get called when `!kernel_set_to_readonly`? The possibilities I can see are: 1. Early boot before `mark_rodata_ro()` is called. 2. When booting with `rodata=off` or if `CONFIG_STRICT_KERNEL_RWX` is disabled. In that case, `kernel_set_to_readonly` would remain 0. If `rodata=off`, `kernel_set_to_readonly` stays 0 for the entire lifetime of the system! At runtime, any BPF program load, module load, ftrace trampoline creation, kprobe, or any user-triggered syscall that changes page permissions can call `verify_rwx()`. If a W^X change is detected by `verify_rwx()` (e.g. setting RW on an executable page or X on a writable page), `!kernel_set_to_readonly` is true and it executes `pr_warn_once(1, ...)` which crashes the kernel because the format string is really `(char *)0x1`! Let me make sure this checks out. What does `pr_warn_once` actually expand to? I need to check `include/linux/printk.h`: ```c #define pr_warn_once(fmt, ...) \ printk_once(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__) ``` Wait, `pr_fmt(1)` becomes `1`. Then `printk_once(KERN_WARNING 1, ...)`... does this even compile? `KERN_WARNING` becomes `"\001" "4"` which compiles as string concatenation. But `KERN_WARNING 1` attempts to concatenate string with integer, which is undefined behavior! Why did it compile? I need to examine how `pr_fmt` is defined. I should look in `set_memory.c` or check `arch/x86/mm/pat/set_memory.c`.
22/2	2026/09/11 12:38	tool	grepper	0m Error: no matches Args: { "Expression": "pr_fmt", "PathPrefix": "arch/x86/mm/pat/set_memory.c" } Results: { "error": "no matches" }
23/2	2026/09/11 12:38	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 32447 output: 20 thoughts: 103 Thoughts: Deconstructing the Warning Message Okay, let's break this down. I need to understand where this warning is originating, so I'm diving into the kernel code. First, I'm checking `arch/x86/mm/pat/set_memory.c`, thinking that's a likely spot for memory-related warnings. And, nope, no `pr_fmt(fmt)` macro defined there. Right, so, in this context, `pr_fmt(fmt)` is just resolving to `fmt`. Simple enough. Then I see `pr_warn_once(1, ...)`. Expanding that, based on my understanding of how these macros work, leads me to `printk_once(KERN_WARNING 1, ...)`. Ah, `printk_once`. That's the key. Where is that defined? I need to check `include/linux/printk.h`. Gotta see the exact definition of `printk_once` to fully grasp what's happening. I need to know how the "once" aspect is implemented to understand the behavior of the warning.
24/2	2026/09/11 12:38	tool	grepper	0m Args: { "Expression": "#define printk_once" } Results: { "Output": "include/linux/printk.h=407=struct pi_entry {\n--\ninclude/linux/printk.h-648-#ifdef CONFIG_PRINTK\ninclude/linux/printk.h:649:#define printk_once(fmt, ...)\t\t\t\t\t\\\ninclude/linux/printk.h-650-\tDO_ONCE_LITE(printk, fmt, ##__VA_ARGS__)\n--\ninclude/linux/printk.h-653-#else\ninclude/linux/printk.h:654:#define printk_once(fmt, ...)\t\t\t\t\t\\\ninclude/linux/printk.h-655-\tno_printk(fmt, ##__VA_ARGS__)\n" }
25/2	2026/09/11 12:38	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 32975 output: 32 thoughts: 87 Thoughts: Okay, let's break this down. Investigating a Kernel Logging Issue Alright, first things first, I need to check out this `DO_ONCE_LITE` macro. It looks like it's being used with `printk`, which immediately flags something important. `DO_ONCE_LITE(printk, KERN_WARNING 1, ...)`...wait a second. That `KERN_WARNING 1` looks wrong. In standard C syntax, that's almost certainly a syntax error unless something funky is happening with how `KERN_WARNING` is defined. Something is making me think that it is not being properly prefixed. Okay, let's pause and investigate `KERN_WARNING` to see what is going on. I know this is going to be in an include file. I'll need to check `include/linux/kern_levels.h` to see exactly how that is defined and what it is meant to represent.
26/2	2026/09/11 12:39	tool	grepper	0m Args: { "Expression": "KERN_WARNING", "PathPrefix": "include/linux/kern_levels.h" } Results: { "Output": "include/linux/kern_levels.h-11-#define KERN_ERR\tKERN_SOH \"3\"\t/* error conditions /\ninclude/linux/kern_levels.h:12:#define KERN_WARNING\tKERN_SOH \"4\"\t/ warning conditions /\ninclude/linux/kern_levels.h-13-#define KERN_NOTICE\tKERN_SOH \"5\"\t/ normal but significant condition */\n" }
27/2	2026/09/11 12:39	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 33407 output: 41 thoughts: 418 Thoughts: My Assessment of the Potential Fuzzing Target Okay, so `KERN_WARNING` is defined as `"\001" "4"`. That immediately raises a red flag. `KERN_WARNING 1` expands to `"\001" "4" 1`, which is obviously a C compiler syntax error. This confirms my initial suspicion – the patch author either didn't test this properly, or a bug was introduced! This is a good sign, and it means we need to dig deeper. The changes are within `arch/x86/mm/pat/set_memory.c`, which, as I know, is a critical part of the x86 memory management system (Change Page Attributes, or CPA). Now, the important question: is this worth fuzzing? Let's break it down: 1. Core Subsystem: `arch/x86/mm/pat/set_memory.c` is definitely a core subsystem, dealing directly with x86 memory management. Check. 2. Reachable: Yes, CPA is reachable through a multitude of syscalls and kernel operations on amd64 systems. Things like BPF JIT, module loading/unloading, tracepoints/kprobes, and the `set_memory_` callers, all can potentially trigger issues. Check. 3. Defensive Checks:* The patch modifies defensive checks and W^X violation verification logic in `verify_rwx()`. Check. Considering the criteria from the instructions (Section 3), it looks like this is a strong candidate: * Memory management modifications are a go. * The modification is altering defensive checks in reachable paths. Therefore, `WorthFuzzing` is definitively `true`. Now let's determine the FocusSymbols. I need to identify which symbols to focus on during fuzzing. I'll start by checking the functions in `arch/x86/mm/pat/set_memory.c` that are called or involved. It seems `arch/x86/mm/pat/set_memory.c` is the right place to look.
28/2	2026/09/11 12:39	tool	grepper	0m Args: { "Expression": "^int set_memory_", "PathPrefix": "arch/x86/mm/pat/set_memory.c" } Results: { "Output": "arch/x86/mm/pat/set_memory.c=2194=int _set_memory_uc(unsigned long addr, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2206-\narch/x86/mm/pat/set_memory.c:2207:int set_memory_uc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2208-{\n--\narch/x86/mm/pat/set_memory.c=2232=int _set_memory_wc(unsigned long addr, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2247-\narch/x86/mm/pat/set_memory.c:2248:int set_memory_wc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2249-{\n--\narch/x86/mm/pat/set_memory.c=2271=int _set_memory_wb(unsigned long addr, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2277-\narch/x86/mm/pat/set_memory.c:2278:int set_memory_wb(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2279-{\n--\narch/x86/mm/pat/set_memory.c=2329=EXPORT_SYMBOL_GPL(clear_mce_nospec);\n--\narch/x86/mm/pat/set_memory.c-2331-\narch/x86/mm/pat/set_memory.c:2332:int set_memory_x(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2333-{\n--\narch/x86/mm/pat/set_memory.c-2339-\narch/x86/mm/pat/set_memory.c:2340:int set_memory_nx(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2341-{\n--\narch/x86/mm/pat/set_memory.c-2347-\narch/x86/mm/pat/set_memory.c:2348:int set_memory_ro(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2349-{\n--\narch/x86/mm/pat/set_memory.c-2352-\narch/x86/mm/pat/set_memory.c:2353:int set_memory_rox(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2354-{\n--\narch/x86/mm/pat/set_memory.c-2363-\narch/x86/mm/pat/set_memory.c:2364:int set_memory_rw(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2365-{\n--\narch/x86/mm/pat/set_memory.c-2368-\narch/x86/mm/pat/set_memory.c:2369:int set_memory_np(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2370-{\n--\narch/x86/mm/pat/set_memory.c-2373-\narch/x86/mm/pat/set_memory.c:2374:int set_memory_np_noalias(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2375-{\n--\narch/x86/mm/pat/set_memory.c-2380-\narch/x86/mm/pat/set_memory.c:2381:int set_memory_p(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2382-{\n--\narch/x86/mm/pat/set_memory.c-2385-\narch/x86/mm/pat/set_memory.c:2386:int set_memory_4k(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2387-{\n--\narch/x86/mm/pat/set_memory.c-2392-\narch/x86/mm/pat/set_memory.c:2393:int set_memory_nonglobal(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2394-{\n--\narch/x86/mm/pat/set_memory.c-2398-\narch/x86/mm/pat/set_memory.c:2399:int set_memory_global(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2400-{\n--\narch/x86/mm/pat/set_memory.c=2495=static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)\n--\narch/x86/mm/pat/set_memory.c-2510-\narch/x86/mm/pat/set_memory.c:2511:int set_memory_encrypted(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2512-{\n--\narch/x86/mm/pat/set_memory.c=2515=EXPORT_SYMBOL_GPL(set_memory_encrypted);\narch/x86/mm/pat/set_memory.c-2516-\narch/x86/mm/pat/set_memory.c:2517:int set_memory_decrypted(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2518-{\n" }
29/2	2026/09/11 12:39	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 35907 output: 44 thoughts: 80 Thoughts: Here's my thought process, as if I were analyzing this code: Analyzing the Call Sites of `verify_rwx` Okay, so `verify_rwx` is a static inline function, which is a key piece of information. I immediately note it's defined in `arch/x86/mm/pat/set_memory.c`. Now, I need to understand its usage within that file. The fact that it's inline suggests it's likely called a few times in strategically placed spots. My immediate priority is to understand where `verify_rwx` gets invoked. That will inform its purpose. I'll focus my search on `arch/x86/mm/pat/set_memory.c`, specifically around line numbers 1067 and 1882. I expect to see the calls there, which should give me the context I need. From there, I can determine the role of `verify_rwx` in the system.
30/2	2026/09/11 12:39	tool	read-file	0m Args: { "File": "arch/x86/mm/pat/set_memory.c", "FirstLine": 1060, "LineCount": 30 } Results: { "Contents": "1060:\t\t/\n1061:\t\t Check whether the requested pgprot is conflicting with a static\n1062:\t\t * protection requirement in the large page.\n1063:\t\t /\n1064:\t\tnew_prot = static_protections(req_prot, lpaddr, old_pfn, numpages,\n1065:\t\t\t\t\t psize, CPA_DETECT);\n1066:\t\n1067:\t\tnew_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages,\n1068:\t\t\t\t nx, rw);\n1069:\t\n1070:\t\t/\n1071:\t\t * If there is a conflict, split the large page.\n1072:\t\t \n1073:\t\t There used to be a 4k wise evaluation trying really hard to\n1074:\t\t * preserve the large pages, but experimentation has shown, that this\n1075:\t\t * does not help at all. There might be corner cases which would\n1076:\t\t * preserve one large page occasionally, but it's really not worth the\n1077:\t\t * extra code and cycles for the common case.\n1078:\t\t /\n1079:\t\tif (pgprot_val(req_prot) != pgprot_val(new_prot))\n1080:\t\t\treturn 1;\n1081:\t\n1082:\t\t/ All checks passed. Update the large page mapping. */\n1083:\t\tnew_pte = pfn_pte(old_pfn, new_prot);\n1084:\t\t__set_pmd_pte(kpte, address, new_pte);\n1085:\t\tcpa-\u003eflags \|= CPA_FLUSHTLB;\n1086:\t\tcpa_inc_lp_preserved(level);\n1087:\t\treturn 0;\n1088:\t}\n1089:\t\n" }
31/2	2026/09/11 12:39	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 36734 output: 44 thoughts: 29 Thoughts: Okay, here's my interpretation of that thought as a first-person expert summary: Digging into Memory Attribute Table (PAT) Behavior Right, so we're looking at some memory management shenanigans, and the PAT is probably involved. My initial hunch is to take a look at `arch/x86/mm/pat/set_memory.c`, specifically line 1882. This strongly suggests that there's a specific set memory operation related to the PAT that I want to investigate, likely involving how memory attributes are being set. Given the complexity of the PAT and its impact on performance and caching, something on this line will probably give some good clues on what needs looking at. It's likely involved in updating the MTRR or PAT entries. This is where the magic happens, so checking this particular spot is crucial to understanding the underlying mechanism.
32/2	2026/09/11 12:39	tool	read-file	0m Args: { "File": "arch/x86/mm/pat/set_memory.c", "FirstLine": 1870, "LineCount": 35 } Results: { "Contents": "1870:\t\t\tpgprot_t old_prot = pte_pgprot(old_pte);\n1871:\t\t\tpgprot_t new_prot = pte_pgprot(old_pte);\n1872:\t\t\tunsigned long pfn = pte_pfn(old_pte);\n1873:\t\n1874:\t\t\tpgprot_val(new_prot) \u0026= ~pgprot_val(cpa-\u003emask_clr);\n1875:\t\t\tpgprot_val(new_prot) \|= pgprot_val(cpa-\u003emask_set);\n1876:\t\n1877:\t\t\tcpa_inc_4k_install();\n1878:\t\t\t/* Hand in lpsize = 0 to enforce the protection mechanism /\n1879:\t\t\tnew_prot = static_protections(new_prot, address, pfn, 1, 0,\n1880:\t\t\t\t\t\t CPA_PROTECT);\n1881:\t\n1882:\t\t\tnew_prot = verify_rwx(old_prot, new_prot, address, pfn, 1,\n1883:\t\t\t\t\t nx, rw);\n1884:\t\n1885:\t\t\tnew_prot = pgprot_clear_protnone_bits(new_prot);\n1886:\t\n1887:\t\t\t/\n1888:\t\t\t * We need to keep the pfn from the existing PTE,\n1889:\t\t\t * after all we're only going to change its attributes\n1890:\t\t\t * not the memory it points to\n1891:\t\t\t /\n1892:\t\t\tnew_pte = pfn_pte(pfn, new_prot);\n1893:\t\t\tcpa-\u003epfn = pfn;\n1894:\t\t\t/\n1895:\t\t\t * Do we really change anything ?\n1896:\t\t\t */\n1897:\t\t\tif (pte_val(old_pte) != pte_val(new_pte)) {\n1898:\t\t\t\tset_pte_atomic(kpte, new_pte);\n1899:\t\t\t\tcpa-\u003eflags \|= CPA_FLUSHTLB;\n1900:\t\t\t}\n1901:\t\t\tcpa-\u003enumpages = 1;\n1902:\t\t\treturn 0;\n1903:\t\t}\n1904:\t\n" }
33/2	2026/09/11 12:39	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 37578 output: 41 thoughts: 57 Thoughts: Here's my take on the thought process, as requested: Digging into the Page Attribute Management Okay, so `verify_rwx()` pops up in two key places: `__should_split_large_page` and `__change_page_attr`. I need to figure out the interplay here, and the potential impact. It looks like it's guarding against something, likely a bad page state. I need to understand what's triggering `__change_page_attr`. That function is crucial because it seems to be the place where permissions are actually getting modified. I should examine the call graph to that function to understand all of the use cases. Knowing the callers will expose the contexts in which these attributes are being changed, and therefore, potentially where `verify_rwx()` is protecting something.
34/2	2026/09/11 12:39	tool	grepper	0m Args: { "Expression": "__change_page_attr", "PathPrefix": "arch/x86/mm/pat/set_memory.c" } Results: { "Output": "arch/x86/mm/pat/set_memory.c=1805=static int __cpa_process_fault(struct cpa_data cpa, unsigned long vaddr,\n--\narch/x86/mm/pat/set_memory.c-1849-\narch/x86/mm/pat/set_memory.c:1850:static int __change_page_attr(struct cpa_data cpa, int primary)\narch/x86/mm/pat/set_memory.c-1851-{\n--\narch/x86/mm/pat/set_memory.c-1927-\narch/x86/mm/pat/set_memory.c:1928:static int __change_page_attr_set_clr(struct cpa_data cpa, int primary);\narch/x86/mm/pat/set_memory.c-1929-\n--\narch/x86/mm/pat/set_memory.c=1933=static int cpa_process_alias(struct cpa_data cpa)\n--\narch/x86/mm/pat/set_memory.c-1963-\narch/x86/mm/pat/set_memory.c:1964:\t\tret = __change_page_attr_set_clr(\u0026alias_cpa, 0);\narch/x86/mm/pat/set_memory.c-1965-\t\tif (ret)\n--\narch/x86/mm/pat/set_memory.c-1997-\t\t /\narch/x86/mm/pat/set_memory.c:1998:\t\t__change_page_attr_set_clr(\u0026alias_cpa, 0);\narch/x86/mm/pat/set_memory.c-1999-\t}\n--\narch/x86/mm/pat/set_memory.c-2004-\narch/x86/mm/pat/set_memory.c:2005:static int __change_page_attr_set_clr(struct cpa_data cpa, int primary)\narch/x86/mm/pat/set_memory.c-2006-{\n--\narch/x86/mm/pat/set_memory.c-2053-\t\t\tguard(spinlock)(\u0026cpa_lock);\narch/x86/mm/pat/set_memory.c:2054:\t\t\tret = __change_page_attr(cpa, primary);\narch/x86/mm/pat/set_memory.c-2055-\t\t} else {\narch/x86/mm/pat/set_memory.c:2056:\t\t\tret = __change_page_attr(cpa, primary);\narch/x86/mm/pat/set_memory.c-2057-\t\t}\n--\narch/x86/mm/pat/set_memory.c=2083=static int change_page_attr_set_clr(unsigned long addr, int numpages,\n--\narch/x86/mm/pat/set_memory.c-2138-\narch/x86/mm/pat/set_memory.c:2139:\tret = __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2140-\n--\narch/x86/mm/pat/set_memory.c=2409=static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)\n--\narch/x86/mm/pat/set_memory.c-2438-\narch/x86/mm/pat/set_memory.c:2439:\tret = __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2440-\n--\narch/x86/mm/pat/set_memory.c=2636=static int __set_pages_p(struct page page, int numpages, unsigned int cpa_flags)\n--\narch/x86/mm/pat/set_memory.c-2651-\t /\narch/x86/mm/pat/set_memory.c:2652:\treturn __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2653-}\n--\narch/x86/mm/pat/set_memory.c=2655=static int __set_pages_np(struct page page, int numpages, unsigned int cpa_flags)\n--\narch/x86/mm/pat/set_memory.c-2670-\t /\narch/x86/mm/pat/set_memory.c:2671:\treturn __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2672-}\n--\narch/x86/mm/pat/set_memory.c=2746=int __init kernel_map_pages_in_pgd(pgd_t pgd, u64 pfn, unsigned long address,\n--\narch/x86/mm/pat/set_memory.c-2770-\narch/x86/mm/pat/set_memory.c:2771:\tretval = __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2772-\t__flush_tlb_all();\n--\narch/x86/mm/pat/set_memory.c=2783=int __init kernel_unmap_pages_in_pgd(pgd_t *pgd, unsigned long address,\n--\narch/x86/mm/pat/set_memory.c-2805-\narch/x86/mm/pat/set_memory.c:2806:\tretval = __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2807-\t__flush_tlb_all();\n" }
35/2	2026/09/11 12:39	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 39416 output: 30 thoughts: 385 Thoughts: Analyzing the set_memory.c Module Okay, let's break this down. My initial focus is on `verify_rwx`, and I see it's a static inline within `arch/x86/mm/pat/set_memory.c`. Given that, I want to map out the relevant symbols within that file and determine which ones are exported (or non-static functions) that call or include `verify_rwx`. So, from the looks of it the relevant symbols in `arch/x86/mm/pat/set_memory.c` are: `__change_page_attr`, `__change_page_attr_set_clr`, `change_page_attr_set_clr`, `set_memory_ro`, `set_memory_rw`, `set_memory_x`, `set_memory_nx`, `set_memory_rox`, `set_memory_uc`, `set_memory_wc`, `set_memory_wb`, `set_memory_np`, `set_memory_p`, `set_memory_4k`, `set_memory_encrypted`, and `set_memory_decrypted`. Now, I'll need to figure out which of those are actually exported or non-static functions or functions that include `verify_rwx`. My immediate candidates are: `set_memory_ro`, `set_memory_rw`, `set_memory_x`, `set_memory_nx`, `set_memory_rox`, `set_memory_uc`, `set_memory_wb`, `change_page_attr_set_clr`, and `__change_page_attr`. Next, I need to check the Kconfig dependencies for `arch/x86/mm/pat/set_memory.c` to see if there's any conditional compilation or other settings that impact its inclusion or behavior. I'll need to look at `arch/x86/mm/Makefile` or `arch/x86/mm/pat/Makefile` to do this. This should give me a more complete picture of the context.
36/2	2026/09/11 12:39	tool	grepper	0m Args: { "Expression": "set_memory", "PathPrefix": "arch/x86/mm" } Results: { "Output": "arch/x86/mm/init.c-11-\narch/x86/mm/init.c:12:#include \u003casm/set_memory.h\u003e\narch/x86/mm/init.c-13-#include \u003casm/cpu_device_id.h\u003e\n--\narch/x86/mm/init.c=897=void free_init_pages(const char what, unsigned long begin, unsigned long end)\n--\narch/x86/mm/init.c-925-\t\tkmemleak_free_part((void )begin, end - begin);\narch/x86/mm/init.c:926:\t\tset_memory_np(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c-927-\t} else {\n--\narch/x86/mm/init.c-932-\t\t /\narch/x86/mm/init.c:933:\t\tset_memory_nx(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c:934:\t\tset_memory_rw(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c-935-\n--\narch/x86/mm/init.c=946=void free_kernel_image_pages(const char what, void begin, void end)\n--\narch/x86/mm/init.c-969-\tif (IS_ENABLED(CONFIG_X86_64) \u0026\u0026 cpu_feature_enabled(X86_FEATURE_PTI))\narch/x86/mm/init.c:970:\t\tset_memory_np_noalias(begin_ul, len_pages);\narch/x86/mm/init.c-971-}\n--\narch/x86/mm/init_32.c-48-#include \u003casm/setup.h\u003e\narch/x86/mm/init_32.c:49:#include \u003casm/set_memory.h\u003e\narch/x86/mm/init_32.c-50-#include \u003casm/page_types.h\u003e\n--\narch/x86/mm/init_32.c=723=static void mark_nxdata_nx(void)\n--\narch/x86/mm/init_32.c-736-\t\tprintk(KERN_INFO \"NX-protecting the kernel data: %luk\\n\", size \u003e\u003e 10);\narch/x86/mm/init_32.c:737:\tset_memory_nx(start, size \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_32.c-738-}\n--\narch/x86/mm/init_64.c-51-#include \u003casm/numa.h\u003e\narch/x86/mm/init_64.c:52:#include \u003casm/set_memory.h\u003e\narch/x86/mm/init_64.c-53-#include \u003casm/init.h\u003e\n--\narch/x86/mm/init_64.c=1359=void mark_rodata_ro(void)\n--\narch/x86/mm/init_64.c-1369-\t (end - start) \u003e\u003e 10);\narch/x86/mm/init_64.c:1370:\tset_memory_ro(start, (end - start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1371-\n--\narch/x86/mm/init_64.c-1386-\tall_end = roundup((unsigned long)_brk_end, PMD_SIZE);\narch/x86/mm/init_64.c:1387:\tset_memory_nx(text_end, (all_end - text_end) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1388-\n--\narch/x86/mm/init_64.c-1392-\tprintk(KERN_INFO \"Testing CPA: undo %lx-%lx\\n\", start, end);\narch/x86/mm/init_64.c:1393:\tset_memory_rw(start, (end-start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1394-\narch/x86/mm/init_64.c-1395-\tprintk(KERN_INFO \"Testing CPA: again\\n\");\narch/x86/mm/init_64.c:1396:\tset_memory_ro(start, (end-start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1397-#endif\n--\narch/x86/mm/init_64.c-1415-/* Adjustable memory block size /\narch/x86/mm/init_64.c:1416:static unsigned long set_memory_block_size;\narch/x86/mm/init_64.c:1417:int __init set_memory_block_size_order(unsigned int order)\narch/x86/mm/init_64.c-1418-{\n--\narch/x86/mm/init_64.c-1423-\narch/x86/mm/init_64.c:1424:\tset_memory_block_size = size;\narch/x86/mm/init_64.c-1425-\treturn 0;\n--\narch/x86/mm/init_64.c=1428=static unsigned long probe_memory_block_size(void)\n--\narch/x86/mm/init_64.c-1433-\t/ If memory block size has been set, then use it /\narch/x86/mm/init_64.c:1434:\tbz = set_memory_block_size;\narch/x86/mm/init_64.c-1435-\tif (bz)\n--\narch/x86/mm/ioremap.c-22-\narch/x86/mm/ioremap.c:23:#include \u003casm/set_memory.h\u003e\narch/x86/mm/ioremap.c-24-#include \u003casm/e820/api.h\u003e\n--\narch/x86/mm/ioremap.c=45=int ioremap_change_attr(unsigned long vaddr, unsigned long size,\n--\narch/x86/mm/ioremap.c-53-\tdefault:\narch/x86/mm/ioremap.c:54:\t\terr = _set_memory_uc(vaddr, nrpages);\narch/x86/mm/ioremap.c-55-\t\tbreak;\narch/x86/mm/ioremap.c-56-\tcase _PAGE_CACHE_MODE_WC:\narch/x86/mm/ioremap.c:57:\t\terr = _set_memory_wc(vaddr, nrpages);\narch/x86/mm/ioremap.c-58-\t\tbreak;\narch/x86/mm/ioremap.c-59-\tcase _PAGE_CACHE_MODE_WT:\narch/x86/mm/ioremap.c:60:\t\terr = _set_memory_wt(vaddr, nrpages);\narch/x86/mm/ioremap.c-61-\t\tbreak;\narch/x86/mm/ioremap.c-62-\tcase _PAGE_CACHE_MODE_WB:\narch/x86/mm/ioremap.c:63:\t\terr = _set_memory_wb(vaddr, nrpages);\narch/x86/mm/ioremap.c-64-\t\tbreak;\n--\narch/x86/mm/mem_encrypt_amd.c-26-#include \u003casm/bootparam.h\u003e\narch/x86/mm/mem_encrypt_amd.c:27:#include \u003casm/set_memory.h\u003e\narch/x86/mm/mem_encrypt_amd.c-28-#include \u003casm/cacheflush.h\u003e\n--\narch/x86/mm/mem_encrypt_amd.c=57=static inline void __init snp_memcpy(void dst, void src, size_t sz,\n--\narch/x86/mm/mem_encrypt_amd.c-66-\t\t /\narch/x86/mm/mem_encrypt_amd.c:67:\t\tearly_snp_set_memory_shared((unsigned long)__va(paddr), paddr, npages);\narch/x86/mm/mem_encrypt_amd.c-68-\n--\narch/x86/mm/mem_encrypt_amd.c-71-\t\t/* Restore the page state after the memcpy. /\narch/x86/mm/mem_encrypt_amd.c:72:\t\tearly_snp_set_memory_private((unsigned long)__va(paddr), paddr, npages);\narch/x86/mm/mem_encrypt_amd.c-73-\t} else {\n--\narch/x86/mm/mem_encrypt_amd.c=286=static int amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-292-\tif (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) \u0026\u0026 !enc)\narch/x86/mm/mem_encrypt_amd.c:293:\t\tsnp_set_memory_shared(vaddr, npages);\narch/x86/mm/mem_encrypt_amd.c-294-\n--\narch/x86/mm/mem_encrypt_amd.c=299=static int amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-305-\tif (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) \u0026\u0026 enc)\narch/x86/mm/mem_encrypt_amd.c:306:\t\tsnp_set_memory_private(vaddr, npages);\narch/x86/mm/mem_encrypt_amd.c-307-\n--\narch/x86/mm/mem_encrypt_amd.c=358=static void __init __set_clr_pte_enc(pte_t kpte, int level, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-378-\t\t /\narch/x86/mm/mem_encrypt_amd.c:379:\t\tearly_snp_set_memory_shared((unsigned long)__va(d.pa), d.pa, 1);\narch/x86/mm/mem_encrypt_amd.c-380-\t}\n--\narch/x86/mm/mem_encrypt_amd.c-388-\tif (enc)\narch/x86/mm/mem_encrypt_amd.c:389:\t\tearly_snp_set_memory_private((unsigned long)__va(d.pa), d.pa, 1);\narch/x86/mm/mem_encrypt_amd.c-390-}\narch/x86/mm/mem_encrypt_amd.c-391-\narch/x86/mm/mem_encrypt_amd.c:392:static int __init early_set_memory_enc_dec(unsigned long vaddr,\narch/x86/mm/mem_encrypt_amd.c-393-\t\t\t\t\t unsigned long size, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-461-\narch/x86/mm/mem_encrypt_amd.c:462:int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size)\narch/x86/mm/mem_encrypt_amd.c-463-{\narch/x86/mm/mem_encrypt_amd.c:464:\treturn early_set_memory_enc_dec(vaddr, size, false);\narch/x86/mm/mem_encrypt_amd.c-465-}\narch/x86/mm/mem_encrypt_amd.c-466-\narch/x86/mm/mem_encrypt_amd.c:467:int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)\narch/x86/mm/mem_encrypt_amd.c-468-{\narch/x86/mm/mem_encrypt_amd.c:469:\treturn early_set_memory_enc_dec(vaddr, size, true);\narch/x86/mm/mem_encrypt_amd.c-470-}\n--\narch/x86/mm/mem_encrypt_amd.c=543=void __init mem_encrypt_free_decrypted_mem(void)\n--\narch/x86/mm/mem_encrypt_amd.c-560-\tif (sme_me_mask) {\narch/x86/mm/mem_encrypt_amd.c:561:\t\tr = set_memory_encrypted(vaddr, npages);\narch/x86/mm/mem_encrypt_amd.c-562-\t\tif (r) {\n--\narch/x86/mm/pat/Makefile-2-\narch/x86/mm/pat/Makefile:3:obj-y\t\t\t\t:= set_memory.o memtype.o\narch/x86/mm/pat/Makefile-4-\n--\narch/x86/mm/pat/memtype.c=492=static u64 sanitize_phys(u64 address)\n--\narch/x86/mm/pat/memtype.c-496-\t for a \"decoy\" virtual address (bit 63 clear) passed to\narch/x86/mm/pat/memtype.c:497:\t * set_memory_X(). __pa() on a \"decoy\" address results in a\narch/x86/mm/pat/memtype.c-498-\t * physical address with bit 63 set.\n--\narch/x86/mm/pat/set_memory.c-22-#include \u003clinux/cc_platform.h\u003e\narch/x86/mm/pat/set_memory.c:23:#include \u003clinux/set_memory.h\u003e\narch/x86/mm/pat/set_memory.c-24-#include \u003clinux/memregion.h\u003e\n--\narch/x86/mm/pat/set_memory.c=274=static bool __cpa_pfn_in_highmap(unsigned long pfn)\n--\narch/x86/mm/pat/set_memory.c-286- * UC to avoid speculative access logging another error. But passing the\narch/x86/mm/pat/set_memory.c:287: * address of the 1:1 mapping to set_memory_uc() is a fine way to encourage a\narch/x86/mm/pat/set_memory.c-288- * speculative access. So we cheat and flip the top bit of the address. This\n--\narch/x86/mm/pat/set_memory.c=2187=static inline int cpa_clear_pages_array(struct page *pages, int numpages,\n--\narch/x86/mm/pat/set_memory.c-2193-\narch/x86/mm/pat/set_memory.c:2194:int _set_memory_uc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2195-{\n--\narch/x86/mm/pat/set_memory.c-2198-\t If you really need strong UC use ioremap_uc(), but note\narch/x86/mm/pat/set_memory.c:2199:\t * that you cannot override IO areas with set_memory_() as\narch/x86/mm/pat/set_memory.c-2200-\t these helpers cannot work with IO memory.\n--\narch/x86/mm/pat/set_memory.c-2206-\narch/x86/mm/pat/set_memory.c:2207:int set_memory_uc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2208-{\n--\narch/x86/mm/pat/set_memory.c-2218-\narch/x86/mm/pat/set_memory.c:2219:\tret = _set_memory_uc(addr, numpages);\narch/x86/mm/pat/set_memory.c-2220-\tif (ret)\n--\narch/x86/mm/pat/set_memory.c-2229-}\narch/x86/mm/pat/set_memory.c:2230:EXPORT_SYMBOL(set_memory_uc);\narch/x86/mm/pat/set_memory.c-2231-\narch/x86/mm/pat/set_memory.c:2232:int _set_memory_wc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2233-{\n--\narch/x86/mm/pat/set_memory.c-2247-\narch/x86/mm/pat/set_memory.c:2248:int set_memory_wc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2249-{\n--\narch/x86/mm/pat/set_memory.c-2256-\narch/x86/mm/pat/set_memory.c:2257:\tret = _set_memory_wc(addr, numpages);\narch/x86/mm/pat/set_memory.c-2258-\tif (ret)\n--\narch/x86/mm/pat/set_memory.c-2262-}\narch/x86/mm/pat/set_memory.c:2263:EXPORT_SYMBOL(set_memory_wc);\narch/x86/mm/pat/set_memory.c-2264-\narch/x86/mm/pat/set_memory.c:2265:int _set_memory_wt(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2266-{\n--\narch/x86/mm/pat/set_memory.c-2270-\narch/x86/mm/pat/set_memory.c:2271:int _set_memory_wb(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2272-{\n--\narch/x86/mm/pat/set_memory.c-2277-\narch/x86/mm/pat/set_memory.c:2278:int set_memory_wb(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2279-{\n--\narch/x86/mm/pat/set_memory.c-2281-\narch/x86/mm/pat/set_memory.c:2282:\tret = _set_memory_wb(addr, numpages);\narch/x86/mm/pat/set_memory.c-2283-\tif (ret)\n--\narch/x86/mm/pat/set_memory.c-2288-}\narch/x86/mm/pat/set_memory.c:2289:EXPORT_SYMBOL(set_memory_wb);\narch/x86/mm/pat/set_memory.c-2290-\n--\narch/x86/mm/pat/set_memory.c=2293=int set_mce_nospec(unsigned long pfn)\n--\narch/x86/mm/pat/set_memory.c-2302-\t * We would like to just call:\narch/x86/mm/pat/set_memory.c:2303:\t * set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1);\narch/x86/mm/pat/set_memory.c-2304-\t * but doing that would radically increase the odds of a\n--\narch/x86/mm/pat/set_memory.c-2309-\t * that looks just like the one we want, but has bit 63 flipped.\narch/x86/mm/pat/set_memory.c:2310:\t * This relies on set_memory_XX() properly sanitizing any __pa()\narch/x86/mm/pat/set_memory.c-2311-\t * results with __PHYSICAL_MASK or PTE_PFN_MASK.\n--\narch/x86/mm/pat/set_memory.c-2314-\narch/x86/mm/pat/set_memory.c:2315:\trc = set_memory_np(decoy_addr, 1);\narch/x86/mm/pat/set_memory.c-2316-\tif (rc)\n--\narch/x86/mm/pat/set_memory.c=2323=int clear_mce_nospec(unsigned long pfn)\n--\narch/x86/mm/pat/set_memory.c-2326-\narch/x86/mm/pat/set_memory.c:2327:\treturn set_memory_p(addr, 1);\narch/x86/mm/pat/set_memory.c-2328-}\narch/x86/mm/pat/set_memory.c=2329=EXPORT_SYMBOL_GPL(clear_mce_nospec);\n--\narch/x86/mm/pat/set_memory.c-2331-\narch/x86/mm/pat/set_memory.c:2332:int set_memory_x(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2333-{\n--\narch/x86/mm/pat/set_memory.c-2339-\narch/x86/mm/pat/set_memory.c:2340:int set_memory_nx(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2341-{\n--\narch/x86/mm/pat/set_memory.c-2347-\narch/x86/mm/pat/set_memory.c:2348:int set_memory_ro(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2349-{\n--\narch/x86/mm/pat/set_memory.c-2352-\narch/x86/mm/pat/set_memory.c:2353:int set_memory_rox(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2354-{\n--\narch/x86/mm/pat/set_memory.c-2363-\narch/x86/mm/pat/set_memory.c:2364:int set_memory_rw(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2365-{\n--\narch/x86/mm/pat/set_memory.c-2368-\narch/x86/mm/pat/set_memory.c:2369:int set_memory_np(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2370-{\n--\narch/x86/mm/pat/set_memory.c-2373-\narch/x86/mm/pat/set_memory.c:2374:int set_memory_np_noalias(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2375-{\n--\narch/x86/mm/pat/set_memory.c-2380-\narch/x86/mm/pat/set_memory.c:2381:int set_memory_p(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2382-{\n--\narch/x86/mm/pat/set_memory.c-2385-\narch/x86/mm/pat/set_memory.c:2386:int set_memory_4k(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2387-{\n--\narch/x86/mm/pat/set_memory.c-2392-\narch/x86/mm/pat/set_memory.c:2393:int set_memory_nonglobal(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2394-{\n--\narch/x86/mm/pat/set_memory.c-2398-\narch/x86/mm/pat/set_memory.c:2399:int set_memory_global(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2400-{\n--\narch/x86/mm/pat/set_memory.c-2405-/\narch/x86/mm/pat/set_memory.c:2406: __set_memory_enc_pgtable() is used for the hypervisors that get\narch/x86/mm/pat/set_memory.c-2407- * informed about \"encryption\" status via page tables.\narch/x86/mm/pat/set_memory.c-2408- /\narch/x86/mm/pat/set_memory.c:2409:static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)\narch/x86/mm/pat/set_memory.c-2410-{\n--\narch/x86/mm/pat/set_memory.c=2473=static DECLARE_RWSEM(mem_enc_lock);\n--\narch/x86/mm/pat/set_memory.c-2480- /\narch/x86/mm/pat/set_memory.c:2481:bool set_memory_enc_stop_conversion(void)\narch/x86/mm/pat/set_memory.c-2482-{\n--\narch/x86/mm/pat/set_memory.c-2494-\narch/x86/mm/pat/set_memory.c:2495:static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)\narch/x86/mm/pat/set_memory.c-2496-{\n--\narch/x86/mm/pat/set_memory.c-2502-\narch/x86/mm/pat/set_memory.c:2503:\t\tret = __set_memory_enc_pgtable(addr, numpages, enc);\narch/x86/mm/pat/set_memory.c-2504-\n--\narch/x86/mm/pat/set_memory.c-2510-\narch/x86/mm/pat/set_memory.c:2511:int set_memory_encrypted(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2512-{\narch/x86/mm/pat/set_memory.c:2513:\treturn __set_memory_enc_dec(addr, numpages, true);\narch/x86/mm/pat/set_memory.c-2514-}\narch/x86/mm/pat/set_memory.c:2515:EXPORT_SYMBOL_GPL(set_memory_encrypted);\narch/x86/mm/pat/set_memory.c-2516-\narch/x86/mm/pat/set_memory.c:2517:int set_memory_decrypted(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2518-{\narch/x86/mm/pat/set_memory.c:2519:\treturn __set_memory_enc_dec(addr, numpages, false);\narch/x86/mm/pat/set_memory.c-2520-}\narch/x86/mm/pat/set_memory.c:2521:EXPORT_SYMBOL_GPL(set_memory_decrypted);\narch/x86/mm/pat/set_memory.c-2522-\narch/x86/mm/pat/set_memory.c=2523=int set_pages_uc(struct page page, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2526-\narch/x86/mm/pat/set_memory.c:2527:\treturn set_memory_uc(addr, numpages);\narch/x86/mm/pat/set_memory.c-2528-}\n--\narch/x86/mm/pat/set_memory.c=2589=int set_pages_wb(struct page page, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2592-\narch/x86/mm/pat/set_memory.c:2593:\treturn set_memory_wb(addr, numpages);\narch/x86/mm/pat/set_memory.c-2594-}\n--\narch/x86/mm/pat/set_memory.c=2622=int set_pages_ro(struct page page, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2625-\narch/x86/mm/pat/set_memory.c:2626:\treturn set_memory_ro(addr, numpages);\narch/x86/mm/pat/set_memory.c-2627-}\n--\narch/x86/mm/pat/set_memory.c=2629=int set_pages_rw(struct page page, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2632-\narch/x86/mm/pat/set_memory.c:2633:\treturn set_memory_rw(addr, numpages);\narch/x86/mm/pat/set_memory.c-2634-}\n--\narch/x86/mm/pti.c-40-#include \u003casm/sections.h\u003e\narch/x86/mm/pti.c:41:#include \u003casm/set_memory.h\u003e\narch/x86/mm/pti.c-42-#include \u003casm/bugs.h\u003e\n--\narch/x86/mm/pti.c=571=static void pti_clone_kernel_text(void)\n--\narch/x86/mm/pti.c-600-\t/* Set the global bit for normal non-__init kernel text: /\narch/x86/mm/pti.c:601:\tset_memory_global(start, (end_global - start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/pti.c-602-}\n--\narch/x86/mm/pti.c=604=static void pti_set_kernel_image_nonglobal(void)\n--\narch/x86/mm/pti.c-619-\t /\narch/x86/mm/pti.c:620:\tset_memory_nonglobal(start, (end - start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/pti.c-621-}\n" }
37/2	2026/09/11 12:39	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 48405 output: 32 thoughts: 89 Thoughts: My Assessment of the x86 Memory Protection Code Okay, so `arch/x86/mm/pat/set_memory.c` is always compiled into the x86 kernel; that's good to know – it's fundamental. The `Makefile` confirms this (`obj-y := set_memory.o memtype.o`). Now, my immediate thought is to check if its behaviour is tied to some configuration options. I need to see if `STRICT_KERNEL_RWX` or something related to Control-Flow Attenuation (CPA), like the `CPA` macro, has any influence on its operation. A quick inspection of `arch/x86/Kconfig` should reveal any relevant configuration dependencies and whether I need to consider those in my analysis.
38/2	2026/09/11 12:39	tool	grepper	0m Args: { "Expression": "STRICT_KERNEL_RWX", "PathPrefix": "arch/x86" } Results: { "Output": "arch/x86/Kconfig=58=config X86\n--\narch/x86/Kconfig-107-\tselect ARCH_HAS_SET_DIRECT_MAP\narch/x86/Kconfig:108:\tselect ARCH_HAS_STRICT_KERNEL_RWX\narch/x86/Kconfig-109-\tselect ARCH_HAS_STRICT_MODULE_RWX\n--\narch/x86/kernel/alternative.c=172=static void its_fini_core(void)\narch/x86/kernel/alternative.c-173-{\narch/x86/kernel/alternative.c:174:\tif (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))\narch/x86/kernel/alternative.c-175-\t\tits_pages_protect(\u0026its_pages);\n--\narch/x86/mm/pat/set_memory.c=671=static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,\n--\narch/x86/mm/pat/set_memory.c-703-\t * false positive.\narch/x86/mm/pat/set_memory.c:704:\t * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,\narch/x86/mm/pat/set_memory.c-705-\t * the warning can be removed completely.\n" }
39/2	2026/09/11 12:39	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 49064 output: 21 thoughts: 27 Thoughts: Okay, here's my take on those thoughts, framed as an expert's inner monologue: Investigating `STRICT_KERNEL_RWX` Configuration Alright, before I dive into the deep end, let's just quickly confirm where `STRICT_KERNEL_RWX` is defined within the kernel's configuration system. I suspect it's either in the general initialization config, `init/Kconfig`, or perhaps a more architecture-specific file, like `arch/Kconfig`. It's critical to know exactly where this config option is defined to understand its scope and how it's handled during build and configuration time. I need to pinpoint the exact location to properly assess its impact and how I can, if necessary, customize or override this default behavior. Time to crack open those Kconfig files!
40/2	2026/09/11 12:39	tool	grepper	0m Args: { "Expression": "config STRICT_KERNEL_RWX" } Results: { "Output": "arch/Kconfig=1595=config ARCH_HAS_STRICT_KERNEL_RWX\n--\narch/Kconfig-1597-\narch/Kconfig:1598:config STRICT_KERNEL_RWX\narch/Kconfig-1599-\tbool \"Make kernel text and rodata read-only\" if ARCH_OPTIONAL_KERNEL_RWX\n" }
41/2	2026/09/11 12:39	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 49386 output: 33 thoughts: 18 Thoughts: Here's my take on the thought process: Diving into the Kernel Configuration Okay, time to get down to brass tacks. I need to investigate something related to kernel configuration, and my gut feeling tells me it's likely housed in `arch/Kconfig`. I'm reasonably sure of that directory, it's where the architectural-specific configurations usually live. I'll focus my search around line 1598. No need to get distracted by a wider search when I have a good idea where to start digging. Let's see what's brewing in that particular area of the config file. Time to open that file and get to it.
42/2	2026/09/11 12:39	tool	read-file	0m Args: { "File": "arch/Kconfig", "FirstLine": 1595, "LineCount": 20 } Results: { "Contents": "1595:\tconfig ARCH_HAS_STRICT_KERNEL_RWX\n1596:\t\tdef_bool n\n1597:\t\n1598:\tconfig STRICT_KERNEL_RWX\n1599:\t\tbool \"Make kernel text and rodata read-only\" if ARCH_OPTIONAL_KERNEL_RWX\n1600:\t\tdepends on ARCH_HAS_STRICT_KERNEL_RWX\n1601:\t\tdefault !ARCH_OPTIONAL_KERNEL_RWX \|\| ARCH_OPTIONAL_KERNEL_RWX_DEFAULT\n1602:\t\thelp\n1603:\t\t If this is set, kernel text and rodata memory will be made read-only,\n1604:\t\t and non-text memory will be made non-executable. This provides\n1605:\t\t protection against certain security exploits (e.g. executing the heap\n1606:\t\t or modifying text)\n1607:\t\n1608:\t\t These features are considered standard security practice these days.\n1609:\t\t You should say Y here in almost all cases.\n1610:\t\n1611:\tconfig ARCH_HAS_STRICT_MODULE_RWX\n1612:\t\tdef_bool n\n1613:\t\n1614:\tconfig STRICT_MODULE_RWX\n" }
43/2	2026/09/11 12:39	llm	patch-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 49912 output: 210 thoughts: 1060 Thoughts: Analysis of W^X Verification Logic in x86 Memory Management Okay, let's break this down. First, I confirmed that `STRICT_KERNEL_RWX` defaults to `y`, so we're good there. The configuration context is crucial: we're dealing with `EnableConfigs`: `["STRICT_KERNEL_RWX"]`. Now, let's hone in on the core of the matter. The `FocusSymbols` are carefully selected to avoid the noise of ubiquitous functions like `vfree` or `kmalloc`. Instead, I'm concentrating on the specific entry points and related functions within `arch/x86/mm/pat/set_memory.c`. Specifically, I'm focusing on the `change_page_attr_set_clr`, `__change_page_attr_set_clr`, `__change_page_attr`, `__should_split_large_page`, `set_memory_ro`, `set_memory_rw`, `set_memory_rox`, `set_memory_x`, and `set_memory_nx`. These are all relevant functions in the `arch/x86/mm/pat/set_memory.c` file. The git diff confirms the changes. We're modifying the W^X verification logic, specifically in the `verify_rwx` function. The patch introduces a conditional warning related to `kernel_set_to_readonly` and rodata protection. This is significant because it provides a mechanism to handle potential false positives, particularly before the `debug_checkwx()` becomes mandatory. The subsystem is clearly x86 memory management, specifically dealing with Change Page Attributes (CPA). The reachability is well-defined: this code path is fully reachable on x86_64 whenever page protection attributes are modified, which happens frequently (modules, BPF JIT, kprobes/ftrace, direct map manipulation). This makes it highly relevant for fuzzing. Therefore, `WorthFuzzing` should be set to `true`, and the `EnableConfigs` and `FocusSymbols` are appropriate. The patch modifies W^X verification, and this makes it a suitable area for investigation.
44/2	2026/09/11 12:39	tool	set-results	0m Args: { "EnableConfigs": [ "STRICT_KERNEL_RWX" ], "FocusSymbols": [ "__change_page_attr", "__should_split_large_page", "change_page_attr_set_clr", "set_memory_ro", "set_memory_rw", "set_memory_rox", "set_memory_nx", "set_memory_x" ], "Reasoning": "The patch modifies the W^X permission verification logic (verify_rwx) within x86 Change Page Attributes (CPA) in arch/x86/mm/pat/set_memory.c. This is reachable core memory management code executed whenever kernel page protections are adjusted (such as via BPF JIT, ftrace, module loading/unloading, or driver memory attribute changes). It introduces new conditional warning behavior when kernel_set_to_readonly is false.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "STRICT_KERNEL_RWX" ], "FocusSymbols": [ "__change_page_attr", "__should_split_large_page", "change_page_attr_set_clr", "set_memory_ro", "set_memory_rw", "set_memory_rox", "set_memory_nx", "set_memory_x" ], "Reasoning": "The patch modifies the W^X permission verification logic (verify_rwx) within x86 Change Page Attributes (CPA) in arch/x86/mm/pat/set_memory.c. This is reachable core memory management code executed whenever kernel page protections are adjusted (such as via BPF JIT, ftrace, module loading/unloading, or driver memory attribute changes). It introduces new conditional warning behavior when kernel_set_to_readonly is false.", "WorthFuzzing": true }
45/1	2026/09/11 12:39	action	If	0m Args: { "WorthFuzzing": true } Results: null
46/2	2026/09/11 12:39	agent	kmsan-evaluator	0m Model: core Args: null Results: { "KMSANReasoning": "The patch modifies `verify_rwx()` in `arch/x86/mm/pat/set_memory.c` to log a warning via `pr_warn_once` instead of triggering a full `WARN_ONCE` when a W^X violation is detected before kernel text has been marked read-only (`kernel_set_to_readonly` is false). \n\nThis change only touches logging and control flow based on an existing global boolean flag and scalar page-table protection values. It does not introduce any memory allocations, does not touch uninitialized heap/stack memory or structure padding, and does not expose any kernel data to user space. Therefore, there are no uninitialized memory risks, and KMSAN fuzzing is not required.", "NeedsKMSAN": false } Instruction: You are an expert Linux kernel security engineer specializing in kernel memory error detectors (KASAN and KMSAN). Your job is to review the provided patch series and determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer) fuzzing session in addition to standard KASAN fuzzing. CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN: - Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable a comprehensive suite of debugging tools and sanitizers, including KASAN (out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP (locking bugs and deadlocks), UB-sanitizers, and memory corruption checks. - KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap, or page allocations) and kernel-to-user memory info-leaks. Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN, LOCKDEP, OR OTHER STANDARD BUG DETECTORS. A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks that are detected ONLY by KMSAN. Look holistically at the patch series and surrounding code. Even if no direct uninitialized field accesses or new buffer allocations are added in the diff itself, a patch may alter control flow, bounds checking, or data length calculations in ways that change how the rest of the code operates on existing buffers (e.g. allowing uninitialized stack/heap memory to be read, copied to user space, or used in control flow). Do not hesitate to use your code access tools to inspect the surrounding code, called functions, and callers. Set NeedsKMSAN=true ONLY IF the patch introduces or modifies: 1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb attributes, ioctl output arguments, socket options, or BPF buffers) where fields or structure padding might not be fully initialized/zeroed. 2. Conditional logic or branching that depends on potentially uninitialized variables or struct fields. 3. Allocation or initialization of complex data structures where uninitialized fields could be read later in reachable code paths. 4. Bounds checks, lengths, or logic in a way that allows surrounding code to access uninitialized bytes of existing buffers. Set NeedsKMSAN=false IF: - The code changes primarily risk out-of-bounds access, array overflows, NULL pointer dereferences, locking deadlocks, or use-after-free bugs (these are already caught by KASAN, LOCKDEP, or standard bug detectors). - All stack/heap structures touched or introduced by the patch are fully zeroed or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied. - The patch does not introduce any risk of uninitialized memory usage or info-leaks. Use your code access tools to inspect the surrounding code if necessary, then provide detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch. Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit bdd6d4eedaaf432f7fba37c2efc88b8459af8020 Author: syz-cluster <triage@syzkaller.com> Date: Fri Sep 11 12:37:43 2026 +0000 syz-cluster: applied patch under review diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index b3060000da8d1..a4f7fe69e6922 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -697,6 +697,21 @@ static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long star return new; end = start + npg * PAGE_SIZE - 1; + + /* + * If the kernel text is still RWX, gently complain, this could be a + * false positive. + * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX, + * the warning can be removed completely. + */ + if (!kernel_set_to_readonly) { + pr_warn_once(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n", + (unsigned long long)pgprot_val(old), + (unsigned long long)pgprot_val(new), + start, end, pfn); + return new; + } + WARN_ONCE(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n", (unsigned long long)pgprot_val(old), (unsigned long long)pgprot_val(new),
47/3	2026/09/11 12:39	llm	kmsan-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 2336 output: 43 thoughts: 647 Thoughts: Evaluating the Need for KMSAN Fuzzing in `arch/x86/mm/pat/set_memory.c` Okay, here's the deal. I'm being asked to figure out whether a patch in `arch/x86/mm/pat/set_memory.c` warrants KMSAN fuzzing, or if KASAN and the standard detectors are good enough. Let's break this down systematically. First, the risk analysis. This is a pretty straightforward request: it's a defensive security engineering question within Linux kernel QA triage. The severity isn't critical; we're just making sure our bases are covered. So, my action is to provide a complete evaluation. Now, let's dive into the patch itself. Looking at the diff, it appears to be adding a warning related to W^X violations. Specifically, it seems like the patch checks if code is being made writable after being read-only in the kernel text. There's a conditional check here: If the kernel isn't configured for strict read-only text, a warning is printed. Otherwise, `WARN_ONCE` is used. This is clearly related to protecting against code injection vulnerabilities. I'll need to go deeper than just glancing at the diff. I'll use either `read-file` or `grepper` to get the broader context within `arch/x86/mm/pat/set_memory.c`, to understand exactly what this `set_memory.c` code is doing and the potential impact of this change. From there, I can determine if uninitialized memory is a concern in the patched code. Once I get the wider picture, I'll be in a better position to determine if KMSAN fuzzing is necessary, or if standard detectors are adequate.
48/3	2026/09/11 12:39	tool	read-file	0m Args: { "File": "arch/x86/mm/pat/set_memory.c", "FirstLine": 690, "LineCount": 40 } Results: { "Contents": " 690:\t\t\treturn new;\n 691:\t\n 692:\t\tif ((pgprot_val(new) \u0026 (_PAGE_RW \| _PAGE_NX)) != _PAGE_RW)\n 693:\t\t\treturn new;\n 694:\t\n 695:\t\t/* Non-leaf translation entries can disable writing or execution. /\n 696:\t\tif (!rw \|\| nx)\n 697:\t\t\treturn new;\n 698:\t\n 699:\t\tend = start + npg PAGE_SIZE - 1;\n 700:\t\n 701:\t\t/\n 702:\t\t If the kernel text is still RWX, gently complain, this could be a\n 703:\t\t * false positive.\n 704:\t\t * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,\n 705:\t\t * the warning can be removed completely.\n 706:\t\t /\n 707:\t\tif (!kernel_set_to_readonly) {\n 708:\t\t\tpr_warn_once(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 709:\t\t\t (unsigned long long)pgprot_val(old),\n 710:\t\t\t (unsigned long long)pgprot_val(new),\n 711:\t\t\t start, end, pfn);\n 712:\t\t\treturn new;\n 713:\t\t}\n 714:\t\n 715:\t\tWARN_ONCE(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 716:\t\t\t (unsigned long long)pgprot_val(old),\n 717:\t\t\t (unsigned long long)pgprot_val(new),\n 718:\t\t\t start, end, pfn);\n 719:\t\n 720:\t\t/\n 721:\t\t * For now, allow all permission change attempts by returning the\n 722:\t\t * attempted permissions. This can 'return old' to actively\n 723:\t\t * refuse the permission change at a later time.\n 724:\t\t /\n 725:\t\treturn new;\n 726:\t}\n 727:\t\n 728:\t/\n 729:\t * Lookup the page table entry for a virtual address in a specific pgd.\n" }
49/3	2026/09/11 12:39	llm	kmsan-evaluator	0m Model: gemini-3.7-flash Args: null Results: null Tokens: input: 4072 output: 181 thoughts: 502 Thoughts: KMSAN Analysis of the Patch Okay, let's break this down. That `pr_warn_once` usage immediately caught my eye – the first argument looks suspicious. Is it a typo or a macro? In any case, it's not the standard pattern, so I'm filing that away for now. My immediate focus, however, is on whether this patch introduces any new risks regarding uninitialized memory, copies to userspace, or anything KMSAN would flag. The patch modifies `verify_rwx()` in `arch/x86/mm/pat/set_memory.c`. Right, so I ran through my mental checklist: * Allocation? Nope, no stack or heap allocation that could be uninitialized. * User space copy? Not at all. * Uninitialized memory reads? No, the arguments to `verify_rwx()` – `old`, `new`, `start`, `end`, `pfn`, `kernel_set_to_readonly` – are all scalar values, booleans, or `pgprot_t` passed by value. This is a clean bill of health. * Buffer manipulation or bounds checks? Nothing here. * Kernel-to-user memory info-leaks? No. Given all of that, it's a straightforward "NeedsKMSAN = false." Now, let's solidify the reasoning for the record. The patch is changing a `WARN_ONCE` to a `pr_warn_once` in `verify_rwx()`. The change only downgrades the warning if `kernel_set_to_readonly` is false during early boot, when the kernel text permissions are still RWX. It's essentially just a conditional logging change. The code is only working with scalar variables – no uninitialized structures, no writes or copies to userspace, no changes to buffer lengths or calculations. All the information for KMSAN to analyze is scalar and passed by value. Therefore, this patch absolutely does not introduce any KMSAN-relevant issues regarding uninitialized memory or info-leaks. Time to call `set-results`.
50/3	2026/09/11 12:39	tool	set-results	0m Args: { "KMSANReasoning": "The patch modifies `verify_rwx()` in `arch/x86/mm/pat/set_memory.c` to log a warning via `pr_warn_once` instead of triggering a full `WARN_ONCE` when a W^X violation is detected before kernel text has been marked read-only (`kernel_set_to_readonly` is false). \n\nThis change only touches logging and control flow based on an existing global boolean flag and scalar page-table protection values. It does not introduce any memory allocations, does not touch uninitialized heap/stack memory or structure padding, and does not expose any kernel data to user space. Therefore, there are no uninitialized memory risks, and KMSAN fuzzing is not required.", "NeedsKMSAN": false } Results: { "KMSANReasoning": "The patch modifies `verify_rwx()` in `arch/x86/mm/pat/set_memory.c` to log a warning via `pr_warn_once` instead of triggering a full `WARN_ONCE` when a W^X violation is detected before kernel text has been marked read-only (`kernel_set_to_readonly` is false). \n\nThis change only touches logging and control flow based on an existing global boolean flag and scalar page-table protection values. It does not introduce any memory allocations, does not touch uninitialized heap/stack memory or structure padding, and does not expose any kernel data to user space. Therefore, there are no uninitialized memory risks, and KMSAN fuzzing is not required.", "NeedsKMSAN": false }

{
  "EnableConfigs": [
    "STRICT_KERNEL_RWX"
  ],
  "FocusSymbols": [
    "__change_page_attr",
    "__should_split_large_page",
    "change_page_attr_set_clr",
    "set_memory_ro",
    "set_memory_rw",
    "set_memory_rox",
    "set_memory_nx",
    "set_memory_x"
  ],
  "KMSANReasoning": "The patch modifies `verify_rwx()` in `arch/x86/mm/pat/set_memory.c` to log a warning via `pr_warn_once` instead of triggering a full `WARN_ONCE` when a W^X violation is detected before kernel text has been marked read-only (`kernel_set_to_readonly` is false). \n\nThis change only touches logging and control flow based on an existing global boolean flag and scalar page-table protection values. It does not introduce any memory allocations, does not touch uninitialized heap/stack memory or structure padding, and does not expose any kernel data to user space. Therefore, there are no uninitialized memory risks, and KMSAN fuzzing is not required.",
  "NeedsKMSAN": false,
  "Reasoning": "The patch modifies the W^X permission verification logic (verify_rwx) within x86 Change Page Attributes (CPA) in arch/x86/mm/pat/set_memory.c. This is reachable core memory management code executed whenever kernel page protections are adjusted (such as via BPF JIT, ftrace, module loading/unloading, or driver memory attribute changes). It introduces new conditional warning behavior when kernel_set_to_readonly is false.",
  "WorthFuzzing": true
}

{
  "PatchDiff": "commit bdd6d4eedaaf432f7fba37c2efc88b8459af8020\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Fri Sep 11 12:37:43 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c\nindex b3060000da8d1..a4f7fe69e6922 100644\n--- a/arch/x86/mm/pat/set_memory.c\n+++ b/arch/x86/mm/pat/set_memory.c\n@@ -697,6 +697,21 @@ static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long star\n \t\treturn new;\n \n \tend = start + npg * PAGE_SIZE - 1;\n+\n+\t/*\n+\t * If the kernel text is still RWX, gently complain, this could be a\n+\t * false positive.\n+\t * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,\n+\t * the warning can be removed completely.\n+\t */\n+\tif (!kernel_set_to_readonly) {\n+\t\tpr_warn_once(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n+\t\t  (unsigned long long)pgprot_val(old),\n+\t\t  (unsigned long long)pgprot_val(new),\n+\t\t  start, end, pfn);\n+\t\treturn new;\n+\t}\n+\n \tWARN_ONCE(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n \t\t  (unsigned long long)pgprot_val(old),\n \t\t  (unsigned long long)pgprot_val(new),\n"
}

{
  "EnableConfigs": [
    "STRICT_KERNEL_RWX"
  ],
  "FocusSymbols": [
    "__change_page_attr",
    "__should_split_large_page",
    "change_page_attr_set_clr",
    "set_memory_ro",
    "set_memory_rw",
    "set_memory_rox",
    "set_memory_nx",
    "set_memory_x"
  ],
  "Reasoning": "The patch modifies the W^X permission verification logic (verify_rwx) within x86 Change Page Attributes (CPA) in arch/x86/mm/pat/set_memory.c. This is reachable core memory management code executed whenever kernel page protections are adjusted (such as via BPF JIT, ftrace, module loading/unloading, or driver memory attribute changes). It introduces new conditional warning behavior when kernel_set_to_readonly is false.",
  "WorthFuzzing": true
}

You are an expert Linux kernel maintainer and security engineer.
Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller.

IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on internal assumptions. You must actively use your code access
tools to inspect the actual source code, callers, and surrounding context.

================================================================================
1. CORE TRIAGE PHILOSOPHY
================================================================================
The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs,
and newly triggered assertions introduced by the patch series.

- REACHABILITY IS THE PRIMARY GATE:
  Fuzzing can only discover bugs in code that can actually execute in standard virtualized
  environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap).
  If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed,
  regardless of whether it adds assertions or complex logic.

- DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS:
  Patch authors routinely label changes as "cleanups", "refactorings", or state
  "No functional change intended". Do NOT take these claims at face value.
  Code refactorings that rearrange logic, introduce helper functions, or alter state management
  in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs.
  If reachable executable code is modified or refactored, it MUST be fuzzed.

- NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED:
  When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON*, VM_WARN_ON*,
  BUG_ON*, lockdep_assert*) in reachable code paths, it enforces new or stricter invariants.
  Even if the author believes the invariant always holds, fuzzing is essential to verify whether
  an unusual sequence of operations can violate it.

================================================================================
2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA)
================================================================================
Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories:

- Non-kernel and non-executable changes:
  * Modifications to Documentation/, comments, or spelling fixes.
  * User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/)
    that do not affect the compiled kernel image (vmlinux) or kernel modules.
  * Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints
    that do not alter control flow or data structures.
  * Build system or Kconfig changes that do not alter compiled C logic.
- Structurally unreachable hardware:
  * Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed,
    ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU.
- Unreachable execution paths:
  * Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during
    physical PCI hot-unplug or manual sysfs driver unbinding.
  * Code paths exclusive to architectures other than the target architecture.

================================================================================
3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA)
================================================================================
Return WorthFuzzing=true whenever the patch touches reachable executable code, including:
- Core Subsystems:
  * Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/),
    BPF, scheduler, core networking, VFS, or syscall handling.
- Refactorings and Code Cleanups:
  * Any restructuring of reachable data structures, helper abstractions, or algorithm flows.
- Runtime Assertions and Defensive Checks:
  * Any introduction or alteration of assertions (WARN_ON*, VM_WARN_ON*, BUG_ON*, etc.) in reachable paths.
- Reachable Drivers and Protocols:
  * Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.).

================================================================================
4. EXTRACTING FocusSymbols (PREVENTING DILUTION)
================================================================================
When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer:

- AVOID UBIQUITOUS LIFECYCLE HOT-PATHS:
  Do NOT list generic, ubiquitous functions called by almost every program in the corpus
  (including, but not limited to: general memory allocators and deallocators, page fault
  and trap handlers, or core synchronization primitives; this is not an exhaustive list).
  Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused",
  which severely dilutes fuzzing effort away from the actual changes.

- TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS:
  List functions that specifically implement the logic being added or altered, or direct API entrypoints
  for the subsystem feature under review.

- HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h):
  Compiler-inlined static functions (such as static inlines in mm/*.h or include/linux/*.h) lack
  distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters.
  If the changes are primarily in static inline helpers, identify non-static, feature-specific caller
  functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers).

================================================================================
5. IDENTIFYING EnableConfigs
================================================================================
Identify any specific CONFIG_ options required to properly compile and reach the modified code:
- Inspect Kconfig files and #ifdef guards; do not make assumptions.
- Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed.
- Strip any 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4").
Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Target architecture: amd64

For your convenience, here is the diff of the changes:
commit bdd6d4eedaaf432f7fba37c2efc88b8459af8020
Author: syz-cluster <triage@syzkaller.com>
Date:   Fri Sep 11 12:37:43 2026 +0000

    syz-cluster: applied patch under review

diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index b3060000da8d1..a4f7fe69e6922 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -697,6 +697,21 @@ static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long star
 		return new;
 
 	end = start + npg * PAGE_SIZE - 1;
+
+	/*
+	 * If the kernel text is still RWX, gently complain, this could be a
+	 * false positive.
+	 * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,
+	 * the warning can be removed completely.
+	 */
+	if (!kernel_set_to_readonly) {
+		pr_warn_once(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n",
+		  (unsigned long long)pgprot_val(old),
+		  (unsigned long long)pgprot_val(new),
+		  start, end, pfn);
+		return new;
+	}
+
 	WARN_ONCE(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n",
 		  (unsigned long long)pgprot_val(old),
 		  (unsigned long long)pgprot_val(new),

							input: 3124
							output: 43
							thoughts: 74

**Analyzing the Patch and Associated Tools**

Alright, let's dive in. My first instinct is always to get a solid grasp of the patch itself, of course. I need to understand the specifics of what's changed and then put that into context. The logical starting point for this is to examine the relevant code, which in this case seems to be within `arch/x86/mm/pat/set_memory.c`. I will then go ahead and use `read-file` or `grepper` on `arch/x86/mm/pat/set_memory.c`. I have a feeling that inspecting this file will be key to understanding the patch's impact.

{
  "File": "arch/x86/mm/pat/set_memory.c",
  "FirstLine": 680,
  "LineCount": 60
}

{
  "Contents": " 680:\t\t * detection and enforcement there.\n 681:\t\t */\n 682:\t\tif (IS_ENABLED(CONFIG_X86_32))\n 683:\t\t\treturn new;\n 684:\t\n 685:\t\t/* Only verify when NX is supported: */\n 686:\t\tif (!(__supported_pte_mask \u0026 _PAGE_NX))\n 687:\t\t\treturn new;\n 688:\t\n 689:\t\tif (!((pgprot_val(old) ^ pgprot_val(new)) \u0026 (_PAGE_RW | _PAGE_NX)))\n 690:\t\t\treturn new;\n 691:\t\n 692:\t\tif ((pgprot_val(new) \u0026 (_PAGE_RW | _PAGE_NX)) != _PAGE_RW)\n 693:\t\t\treturn new;\n 694:\t\n 695:\t\t/* Non-leaf translation entries can disable writing or execution. */\n 696:\t\tif (!rw || nx)\n 697:\t\t\treturn new;\n 698:\t\n 699:\t\tend = start + npg * PAGE_SIZE - 1;\n 700:\t\n 701:\t\t/*\n 702:\t\t * If the kernel text is still RWX, gently complain, this could be a\n 703:\t\t * false positive.\n 704:\t\t * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,\n 705:\t\t * the warning can be removed completely.\n 706:\t\t */\n 707:\t\tif (!kernel_set_to_readonly) {\n 708:\t\t\tpr_warn_once(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 709:\t\t\t  (unsigned long long)pgprot_val(old),\n 710:\t\t\t  (unsigned long long)pgprot_val(new),\n 711:\t\t\t  start, end, pfn);\n 712:\t\t\treturn new;\n 713:\t\t}\n 714:\t\n 715:\t\tWARN_ONCE(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 716:\t\t\t  (unsigned long long)pgprot_val(old),\n 717:\t\t\t  (unsigned long long)pgprot_val(new),\n 718:\t\t\t  start, end, pfn);\n 719:\t\n 720:\t\t/*\n 721:\t\t * For now, allow all permission change attempts by returning the\n 722:\t\t * attempted permissions.  This can 'return old' to actively\n 723:\t\t * refuse the permission change at a later time.\n 724:\t\t */\n 725:\t\treturn new;\n 726:\t}\n 727:\t\n 728:\t/*\n 729:\t * Lookup the page table entry for a virtual address in a specific pgd.\n 730:\t * Return a pointer to the entry (or NULL if the entry does not exist),\n 731:\t * the level of the entry, and the effective NX and RW bits of all\n 732:\t * page table levels.\n 733:\t */\n 734:\tpte_t *lookup_address_in_pgd_attr(pgd_t *pgd, unsigned long address,\n 735:\t\t\t\t\t  unsigned int *level, bool *nx, bool *rw)\n 736:\t{\n 737:\t\tp4d_t *p4d;\n 738:\t\tpud_t *pud;\n 739:\t\tpmd_t *pmd;\n"
}

							input: 4378
							output: 39
							thoughts: 25

Here's my take on those thoughts:

**Analyzing `verify_rwx` Usage**

Alright, time to get down to brass tacks. I need to understand the scope of the `verify_rwx` function and how it's being utilized within this codebase. To get a clear picture of its influence, I'm going to reach for the tried and true `grep` command. Specifically, I'll search for `verify_rwx` to identify every instance where it's invoked. This will illuminate the surrounding context and reveal the areas of the code that depend on its functionality. This quick scan will set the stage for a deeper dive, allowing me to understand where this function fits into the bigger picture.

{
  "Expression": "verify_rwx",
  "PathPrefix": "arch/x86/mm/pat/set_memory.c"
}

{
  "Output": "arch/x86/mm/pat/set_memory.c=623=static inline pgprot_t static_protections(pgprot_t prot, unsigned long start,\n--\narch/x86/mm/pat/set_memory.c-670- */\narch/x86/mm/pat/set_memory.c:671:static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,\narch/x86/mm/pat/set_memory.c-672-\t\t\t\t  unsigned long pfn, unsigned long npg,\n--\narch/x86/mm/pat/set_memory.c=943=static int __should_split_large_page(pte_t *kpte, unsigned long address,\n--\narch/x86/mm/pat/set_memory.c-1066-\narch/x86/mm/pat/set_memory.c:1067:\tnew_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages,\narch/x86/mm/pat/set_memory.c-1068-\t\t\t      nx, rw);\n--\narch/x86/mm/pat/set_memory.c=1850=static int __change_page_attr(struct cpa_data *cpa, int primary)\n--\narch/x86/mm/pat/set_memory.c-1881-\narch/x86/mm/pat/set_memory.c:1882:\t\tnew_prot = verify_rwx(old_prot, new_prot, address, pfn, 1,\narch/x86/mm/pat/set_memory.c-1883-\t\t\t\t      nx, rw);\n"
}

							input: 5045
							output: 21
							thoughts: 38

Here's my take on those thoughts:

**Analyzing Kernel Functionality**

Okay, let's dive in. My immediate thought is, "Right, I need to understand what's happening here." The goal is to get a handle on this particular code. Specifically, I'm thinking about the interactions between `verify_rwx` and `kernel_set_to_readonly`. I need to figure out what each of these functions does, and how they relate. Given that the goal is to fully analyze the code, it makes sense to start with `kernel_set_to_readonly`. Let's search for the definition and usage of that function first. A good solid definition will give me the best foundation to understand the context and intent of the code.

{
  "Expression": "kernel_set_to_readonly"
}

{
  "Output": "arch/parisc/mm/init.c=112=static void __init setup_bootmem(void)\n--\narch/parisc/mm/init.c-340-\narch/parisc/mm/init.c:341:static bool kernel_set_to_readonly;\narch/parisc/mm/init.c-342-\narch/parisc/mm/init.c=343=static void __ref map_pages(unsigned long start_vaddr,\n--\narch/parisc/mm/init.c-403-\t\t\t\t\tprot = PAGE_KERNEL;\narch/parisc/mm/init.c:404:\t\t\t\t} else if (!kernel_set_to_readonly) {\narch/parisc/mm/init.c-405-\t\t\t\t\t/* still initializing, allow writing to RO memory */\n--\narch/parisc/mm/init.c=489=void mark_rodata_ro(void)\n--\narch/parisc/mm/init.c-496-\narch/parisc/mm/init.c:497:\tkernel_set_to_readonly = true;\narch/parisc/mm/init.c-498-\tmap_pages(start, __pa(start), end - start, PAGE_KERNEL, 0);\n--\narch/x86/include/asm/set_memory.h=92=bool kernel_page_present(struct page *page);\narch/x86/include/asm/set_memory.h-93-\narch/x86/include/asm/set_memory.h:94:extern int kernel_set_to_readonly;\narch/x86/include/asm/set_memory.h-95-\n--\narch/x86/mm/init_32.c=692=void __init mem_init(void)\n--\narch/x86/mm/init_32.c-720-\narch/x86/mm/init_32.c:721:int kernel_set_to_readonly __read_mostly;\narch/x86/mm/init_32.c-722-\n--\narch/x86/mm/init_32.c=740=void mark_rodata_ro(void)\n--\narch/x86/mm/init_32.c-748-\narch/x86/mm/init_32.c:749:\tkernel_set_to_readonly = 1;\narch/x86/mm/init_32.c-750-\n--\narch/x86/mm/init_64.c=1343=void __init mem_init(void)\n--\narch/x86/mm/init_64.c-1356-\narch/x86/mm/init_64.c:1357:int kernel_set_to_readonly;\narch/x86/mm/init_64.c-1358-\narch/x86/mm/init_64.c=1359=void mark_rodata_ro(void)\n--\narch/x86/mm/init_64.c-1371-\narch/x86/mm/init_64.c:1372:\tkernel_set_to_readonly = 1;\narch/x86/mm/init_64.c-1373-\n--\narch/x86/mm/pat/set_memory.c=507=static pgprotval_t protect_pci_bios(unsigned long spfn, unsigned long epfn)\n--\narch/x86/mm/pat/set_memory.c-515- * aliases.  This also includes __ro_after_init, so do not enforce until\narch/x86/mm/pat/set_memory.c:516: * kernel_set_to_readonly is true.\narch/x86/mm/pat/set_memory.c-517- */\narch/x86/mm/pat/set_memory.c=518=static pgprotval_t protect_rodata(unsigned long spfn, unsigned long epfn)\n--\narch/x86/mm/pat/set_memory.c-527-\narch/x86/mm/pat/set_memory.c:528:\tif (kernel_set_to_readonly \u0026\u0026 overlaps(spfn, epfn, spfn_ro, epfn_ro))\narch/x86/mm/pat/set_memory.c-529-\t\treturn _PAGE_RW;\n--\narch/x86/mm/pat/set_memory.c=541=static pgprotval_t protect_kernel_text(unsigned long start, unsigned long end)\n--\narch/x86/mm/pat/set_memory.c-552-/*\narch/x86/mm/pat/set_memory.c:553: * Once the kernel maps the text as RO (kernel_set_to_readonly is set),\narch/x86/mm/pat/set_memory.c-554- * kernel text mappings for the large page aligned text, rodata sections\n--\narch/x86/mm/pat/set_memory.c=561=static pgprotval_t protect_kernel_text_ro(unsigned long start,\n--\narch/x86/mm/pat/set_memory.c-567-\narch/x86/mm/pat/set_memory.c:568:\tif (!kernel_set_to_readonly || !overlaps(start, end, t_start, t_end))\narch/x86/mm/pat/set_memory.c-569-\t\treturn 0;\n--\narch/x86/mm/pat/set_memory.c=671=static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,\n--\narch/x86/mm/pat/set_memory.c-706-\t */\narch/x86/mm/pat/set_memory.c:707:\tif (!kernel_set_to_readonly) {\narch/x86/mm/pat/set_memory.c-708-\t\tpr_warn_once(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n"
}

							input: 6868
							output: 20
							thoughts: 143

**Analyzing the Read-Only Data Marking**

Okay, let's break this down. My initial understanding is that `mark_rodata_ro()` gets invoked during the kernel's boot process, specifically within the functions `mark_readonly()` or directly as `mark_rodata_ro()`. The crucial piece here is that when this function executes during boot, the variable `kernel_set_to_readonly` gets set to a value of 1.

The interesting thing is that after the boot sequence completes, during the standard runtime of the kernel, and even during fuzzing efforts, this `kernel_set_to_readonly` variable *always* retains its value of 1.

But, wait a second... this feels like it might be an oversimplification. Is it truly the case that `kernel_set_to_readonly` is *never* zero after the initial boot? I need to clarify if there's a transient period during the very early stages of the boot process where this variable might be 0, before being initialized to 1. This could be key to understanding potential vulnerabilities or unexpected behavior.

Therefore, I need to verify when `mark_rodata_ro()` is actually called in the boot sequence. Let's do a quick grep search to confirm the call site and see if there are any subtle variations in the call paths.

{
  "Expression": "mark_rodata_ro"
}

{
  "Output": "arch/arm/mm/init.c=392=static void fix_kernmem_perms(void)\n--\narch/arm/mm/init.c-396-\narch/arm/mm/init.c:397:static int __mark_rodata_ro(void *unused)\narch/arm/mm/init.c-398-{\n--\narch/arm/mm/init.c-402-\narch/arm/mm/init.c:403:void mark_rodata_ro(void)\narch/arm/mm/init.c-404-{\narch/arm/mm/init.c:405:\tstop_machine(__mark_rodata_ro, NULL, NULL);\narch/arm/mm/init.c-406-\tarm_debug_checkwx();\n--\narch/arm64/mm/mmu.c=1180=static void __init map_mem(void)\n--\narch/arm64/mm/mmu.c-1253-\narch/arm64/mm/mmu.c:1254:void mark_rodata_ro(void)\narch/arm64/mm/mmu.c-1255-{\n--\narch/parisc/mm/init.c=451=void free_initmem(void)\n--\narch/parisc/mm/init.c-488-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/parisc/mm/init.c:489:void mark_rodata_ro(void)\narch/parisc/mm/init.c-490-{\n--\narch/powerpc/include/asm/book3s/64/hash.h=152=static inline int hash__p4d_bad(p4d_t p4d)\n--\narch/powerpc/include/asm/book3s/64/hash.h-156-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/include/asm/book3s/64/hash.h:157:extern void hash__mark_rodata_ro(void);\narch/powerpc/include/asm/book3s/64/hash.h-158-extern void hash__mark_initmem_nx(void);\n--\narch/powerpc/include/asm/book3s/64/radix.h-141-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/include/asm/book3s/64/radix.h:142:extern void radix__mark_rodata_ro(void);\narch/powerpc/include/asm/book3s/64/radix.h-143-extern void radix__mark_initmem_nx(void);\n--\narch/powerpc/mm/book3s32/mmu.c=196=int mmu_mark_initmem_nx(void)\n--\narch/powerpc/mm/book3s32/mmu.c-235-\narch/powerpc/mm/book3s32/mmu.c:236:int mmu_mark_rodata_ro(void)\narch/powerpc/mm/book3s32/mmu.c-237-{\n--\narch/powerpc/mm/book3s64/hash_pgtable.c=524=static bool hash__change_memory_range(unsigned long start, unsigned long end,\n--\narch/powerpc/mm/book3s64/hash_pgtable.c-564-\narch/powerpc/mm/book3s64/hash_pgtable.c:565:void hash__mark_rodata_ro(void)\narch/powerpc/mm/book3s64/hash_pgtable.c-566-{\n--\narch/powerpc/mm/book3s64/radix_pgtable.c=188=static void radix__change_memory_range(unsigned long start, unsigned long end,\n--\narch/powerpc/mm/book3s64/radix_pgtable.c-230-\narch/powerpc/mm/book3s64/radix_pgtable.c:231:void radix__mark_rodata_ro(void)\narch/powerpc/mm/book3s64/radix_pgtable.c-232-{\n--\narch/powerpc/mm/mmu_decl.h=163=int mmu_mark_initmem_nx(void);\narch/powerpc/mm/mmu_decl.h:164:int mmu_mark_rodata_ro(void);\narch/powerpc/mm/mmu_decl.h-165-#else\narch/powerpc/mm/mmu_decl.h=166=static inline int mmu_mark_initmem_nx(void) { return 0; }\narch/powerpc/mm/mmu_decl.h:167:static inline int mmu_mark_rodata_ro(void) { return 0; }\narch/powerpc/mm/mmu_decl.h-168-#endif\n--\narch/powerpc/mm/nohash/8xx.c=171=int mmu_mark_initmem_nx(void)\n--\narch/powerpc/mm/nohash/8xx.c-188-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/mm/nohash/8xx.c:189:int mmu_mark_rodata_ro(void)\narch/powerpc/mm/nohash/8xx.c-190-{\n--\narch/powerpc/mm/nohash/e500.c=266=void __init adjust_total_lowmem(void)\n--\narch/powerpc/mm/nohash/e500.c-287-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/mm/nohash/e500.c:288:int mmu_mark_rodata_ro(void)\narch/powerpc/mm/nohash/e500.c-289-{\n--\narch/powerpc/mm/nohash/e500.c=301=int mmu_mark_initmem_nx(void)\narch/powerpc/mm/nohash/e500.c-302-{\narch/powerpc/mm/nohash/e500.c:303:\t/* Everything is done in mmu_mark_rodata_ro() */\narch/powerpc/mm/nohash/e500.c-304-\treturn 0;\n--\narch/powerpc/mm/pgtable_32.c=145=void mark_initmem_nx(void)\n--\narch/powerpc/mm/pgtable_32.c-153-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/mm/pgtable_32.c:154:static int __mark_rodata_ro(void)\narch/powerpc/mm/pgtable_32.c-155-{\n--\narch/powerpc/mm/pgtable_32.c-161-\tif (v_block_mapped((unsigned long)_stext + 1))\narch/powerpc/mm/pgtable_32.c:162:\t\treturn mmu_mark_rodata_ro();\narch/powerpc/mm/pgtable_32.c-163-\n--\narch/powerpc/mm/pgtable_32.c-174-\narch/powerpc/mm/pgtable_32.c:175:void mark_rodata_ro(void)\narch/powerpc/mm/pgtable_32.c-176-{\narch/powerpc/mm/pgtable_32.c:177:\tint err = __mark_rodata_ro();\narch/powerpc/mm/pgtable_32.c-178-\n--\narch/powerpc/mm/pgtable_64.c=126=struct page *pmd_page(pmd_t pmd)\n--\narch/powerpc/mm/pgtable_64.c-141-#ifdef CONFIG_STRICT_KERNEL_RWX\narch/powerpc/mm/pgtable_64.c:142:void mark_rodata_ro(void)\narch/powerpc/mm/pgtable_64.c-143-{\n--\narch/powerpc/mm/pgtable_64.c-149-\tif (radix_enabled())\narch/powerpc/mm/pgtable_64.c:150:\t\tradix__mark_rodata_ro();\narch/powerpc/mm/pgtable_64.c-151-\telse\narch/powerpc/mm/pgtable_64.c:152:\t\thash__mark_rodata_ro();\narch/powerpc/mm/pgtable_64.c-153-}\n--\narch/riscv/mm/init.c=732=static __meminit pgprot_t pgprot_from_va(uintptr_t va)\n--\narch/riscv/mm/init.c-740-\t * written.\narch/riscv/mm/init.c:741:\t * And rodata section is marked readonly in mark_rodata_ro.\narch/riscv/mm/init.c-742-\t */\n--\narch/riscv/mm/init.c-748-\narch/riscv/mm/init.c:749:void mark_rodata_ro(void)\narch/riscv/mm/init.c-750-{\n--\narch/s390/mm/init.c=101=void __init paging_init(void)\n--\narch/s390/mm/init.c-106-\narch/s390/mm/init.c:107:void mark_rodata_ro(void)\narch/s390/mm/init.c-108-{\n--\narch/um/kernel/mem.c=131=DECLARE_VM_GET_PAGE_PROT\narch/um/kernel/mem.c-132-\narch/um/kernel/mem.c:133:void mark_rodata_ro(void)\narch/um/kernel/mem.c-134-{\n--\narch/x86/mm/init_32.c=723=static void mark_nxdata_nx(void)\n--\narch/x86/mm/init_32.c-739-\narch/x86/mm/init_32.c:740:void mark_rodata_ro(void)\narch/x86/mm/init_32.c-741-{\n--\narch/x86/mm/init_64.c=1357=int kernel_set_to_readonly;\narch/x86/mm/init_64.c-1358-\narch/x86/mm/init_64.c:1359:void mark_rodata_ro(void)\narch/x86/mm/init_64.c-1360-{\n--\ninclude/linux/cache.h-55- * __ro_after_init is used to mark things that are read-only after init (i.e.\ninclude/linux/cache.h:56: * after mark_rodata_ro() has been called). These are effectively read-only,\ninclude/linux/cache.h-57- * but may get written to during init, so can't live in .rodata (via \"const\").\n--\ninclude/linux/init.h=165=extern bool rodata_enabled;\ninclude/linux/init.h:166:void mark_rodata_ro(void);\ninclude/linux/init.h-167-\n--\ninclude/linux/rodata_test.h-2-/*\ninclude/linux/rodata_test.h:3: * rodata_test.h: functional test for mark_rodata_ro function\ninclude/linux/rodata_test.h-4- *\n--\ninit/main.c=1521=static void mark_readonly(void)\n--\ninit/main.c-1531-\t\tjump_label_init_ro();\ninit/main.c:1532:\t\tmark_rodata_ro();\ninit/main.c-1533-\t\tdebug_checkwx();\n--\nkernel/module/main.c=3088=static noinline int do_init_module(struct module *mod)\n--\nkernel/module/main.c-3188-\t * mappings which won't be cleaned up until do_free_init() runs.  Any\nkernel/module/main.c:3189:\t * code such as mark_rodata_ro() which depends on those mappings to\nkernel/module/main.c-3190-\t * be cleaned up needs to sync with the queued work by invoking\n--\nmm/rodata_test.c-2-/*\nmm/rodata_test.c:3: * rodata_test.c: functional test for mark_rodata_ro function\nmm/rodata_test.c-4- *\n"
}

							input: 10589
							output: 34
							thoughts: 58

Here's my analysis of what I'm looking at, from my expert perspective:

**Investigating `mark_readonly` During Kernel Boot**

Alright, so I need to track down when and where `mark_readonly` is being called, which, as I recall, likely pertains to memory regions. The hint is in `init/main.c`, and more specifically, it's triggered during boot, right around the time the kernel is initializing, before it hands control over to the init process and starts freeing memory allocated during the initial boot sequence. That narrows it down considerably. I'm going to jump into `init/main.c` now and zoom in around line 1521, to find the exact context of that call and try to understand what specific memory regions are being made read-only at that stage. This should give me a good handle on how the kernel is setting up memory protection early on.

{
  "File": "init/main.c",
  "FirstLine": 1515,
  "LineCount": 40
}

{
  "Contents": "1515:\t\t\tpr_warn(\"Invalid option string for rodata: '%s'\\n\", str);\n1516:\t\treturn 0;\n1517:\t}\n1518:\tearly_param(\"rodata\", set_debug_rodata);\n1519:\t#endif\n1520:\t\n1521:\tstatic void mark_readonly(void)\n1522:\t{\n1523:\t\tif (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) \u0026\u0026 rodata_enabled) {\n1524:\t\t\t/*\n1525:\t\t\t * load_module() results in W+X mappings, which are cleaned\n1526:\t\t\t * up with init_free_wq. Let's make sure that queued work is\n1527:\t\t\t * flushed so that we don't hit false positives looking for\n1528:\t\t\t * insecure pages which are W+X.\n1529:\t\t\t */\n1530:\t\t\tflush_module_init_free_work();\n1531:\t\t\tjump_label_init_ro();\n1532:\t\t\tmark_rodata_ro();\n1533:\t\t\tdebug_checkwx();\n1534:\t\t\trodata_test();\n1535:\t\t} else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {\n1536:\t\t\tpr_info(\"Kernel memory protection disabled.\\n\");\n1537:\t\t} else if (IS_ENABLED(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)) {\n1538:\t\t\tpr_warn(\"Kernel memory protection not selected by kernel config.\\n\");\n1539:\t\t} else {\n1540:\t\t\tpr_warn(\"This architecture does not have kernel memory protection.\\n\");\n1541:\t\t}\n1542:\t}\n1543:\t\n1544:\tvoid __weak free_initmem(void)\n1545:\t{\n1546:\t\tfree_initmem_default(POISON_FREE_INITMEM);\n1547:\t}\n1548:\t\n1549:\tstatic int __ref kernel_init(void *unused)\n1550:\t{\n1551:\t\tint ret;\n1552:\t\n1553:\t\tinit_userspace_fs();\n1554:\t\n"
}

							input: 11468
							output: 18
							thoughts: 318

**Investigating a Kernel W^X Violation**

Okay, so I'm looking at this `verify_rwx` function and a potential Write XOR Execute (W^X) violation. The crux of the issue seems to be tied to the `kernel_set_to_readonly` flag, which indicates whether read-only data sections have been properly marked as such. I'm wondering what happens in a few specific scenarios.

First, let's explore what occurs when `!rodata_enabled`, which essentially means the kernel is booted with `rodata=off` on the kernel command line. If that's the case, then `mark_rodata_ro()` is never invoked. Consequently, `kernel_set_to_readonly` remains 0. This lack of setting the flag could be the root cause.

Now, what if there's a situation where early boot code, using `set_memory_*` calls, modifies memory regions *before* `mark_rodata_ro()` is even called? This could also lead to similar problems. I need to keep that timing in mind.

I'm seeing that `verify_rwx` is firing `WARN_ONCE` during boot, indicating a potential W^X issue. This patch modifies the warning logic to include the `kernel_set_to_readonly` check. The idea is, if the flag *isn't* set, we emit a specific warning, and otherwise issue the general W^X warning.

Wait a second, before I dig too deep into the code, I should probably consult `git log` or the commit history around `verify_rwx`. Understanding the context of the change—what problems it was intended to solve and what assumptions were made—will give me a clearer picture of what I'm dealing with. That's the first thing I need to do.

{
  "Expression": "verify_rwx"
}

{
  "Output": "arch/x86/mm/pat/set_memory.c=623=static inline pgprot_t static_protections(pgprot_t prot, unsigned long start,\n--\narch/x86/mm/pat/set_memory.c-670- */\narch/x86/mm/pat/set_memory.c:671:static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,\narch/x86/mm/pat/set_memory.c-672-\t\t\t\t  unsigned long pfn, unsigned long npg,\n--\narch/x86/mm/pat/set_memory.c=943=static int __should_split_large_page(pte_t *kpte, unsigned long address,\n--\narch/x86/mm/pat/set_memory.c-1066-\narch/x86/mm/pat/set_memory.c:1067:\tnew_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages,\narch/x86/mm/pat/set_memory.c-1068-\t\t\t      nx, rw);\n--\narch/x86/mm/pat/set_memory.c=1850=static int __change_page_attr(struct cpa_data *cpa, int primary)\n--\narch/x86/mm/pat/set_memory.c-1881-\narch/x86/mm/pat/set_memory.c:1882:\t\tnew_prot = verify_rwx(old_prot, new_prot, address, pfn, 1,\narch/x86/mm/pat/set_memory.c-1883-\t\t\t\t      nx, rw);\n"
}

							input: 12648
							output: 43
							thoughts: 34

Here's my summary, as though I'm reading and processing the provided information:

**Analyzing `verify_rwx` and Context**

Okay, so we're diving into the `verify_rwx` function, which implies some kind of memory access validation, likely related to read-write-execute permissions. The fact that it's nestled within `arch/x86/mm/pat/set_memory.c` immediately narrows the scope. This suggests we're dealing with the x86 architecture, memory management, potentially including Page Attribute Table (PAT) manipulation, and particularly, the setting of memory attributes. This is a critical area for security and performance optimization, so I need to understand the nuances of how it's implemented. I need to understand the logic flow, the types of validations done and how permissions are enforced. I'll need to examine the function's arguments, return values, and any side effects it may have, such as error reporting or changes to data structures. I'll pay close attention to the data types used and their sizes, as these can tell a lot about the intended usage and potential vulnerabilities. Time to dig in and understand this thoroughly.

{
  "File": "arch/x86/mm/pat/set_memory.c",
  "FirstLine": 660,
  "LineCount": 70
}

{
  "Contents": " 660:\t\n 661:\t\tres = protect_rodata(pfn, pfn + npg - 1);\n 662:\t\tcheck_conflict(warnlvl, prot, res, start, end, pfn, \"Rodata RO\");\n 663:\t\tforbidden |= res;\n 664:\t\n 665:\t\treturn __pgprot(pgprot_val(prot) \u0026 ~forbidden);\n 666:\t}\n 667:\t\n 668:\t/*\n 669:\t * Validate strict W^X semantics.\n 670:\t */\n 671:\tstatic inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,\n 672:\t\t\t\t\t  unsigned long pfn, unsigned long npg,\n 673:\t\t\t\t\t  bool nx, bool rw)\n 674:\t{\n 675:\t\tunsigned long end;\n 676:\t\n 677:\t\t/*\n 678:\t\t * 32-bit has some unfixable W+X issues, like EFI code\n 679:\t\t * and writeable data being in the same page.  Disable\n 680:\t\t * detection and enforcement there.\n 681:\t\t */\n 682:\t\tif (IS_ENABLED(CONFIG_X86_32))\n 683:\t\t\treturn new;\n 684:\t\n 685:\t\t/* Only verify when NX is supported: */\n 686:\t\tif (!(__supported_pte_mask \u0026 _PAGE_NX))\n 687:\t\t\treturn new;\n 688:\t\n 689:\t\tif (!((pgprot_val(old) ^ pgprot_val(new)) \u0026 (_PAGE_RW | _PAGE_NX)))\n 690:\t\t\treturn new;\n 691:\t\n 692:\t\tif ((pgprot_val(new) \u0026 (_PAGE_RW | _PAGE_NX)) != _PAGE_RW)\n 693:\t\t\treturn new;\n 694:\t\n 695:\t\t/* Non-leaf translation entries can disable writing or execution. */\n 696:\t\tif (!rw || nx)\n 697:\t\t\treturn new;\n 698:\t\n 699:\t\tend = start + npg * PAGE_SIZE - 1;\n 700:\t\n 701:\t\t/*\n 702:\t\t * If the kernel text is still RWX, gently complain, this could be a\n 703:\t\t * false positive.\n 704:\t\t * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,\n 705:\t\t * the warning can be removed completely.\n 706:\t\t */\n 707:\t\tif (!kernel_set_to_readonly) {\n 708:\t\t\tpr_warn_once(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 709:\t\t\t  (unsigned long long)pgprot_val(old),\n 710:\t\t\t  (unsigned long long)pgprot_val(new),\n 711:\t\t\t  start, end, pfn);\n 712:\t\t\treturn new;\n 713:\t\t}\n 714:\t\n 715:\t\tWARN_ONCE(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 716:\t\t\t  (unsigned long long)pgprot_val(old),\n 717:\t\t\t  (unsigned long long)pgprot_val(new),\n 718:\t\t\t  start, end, pfn);\n 719:\t\n 720:\t\t/*\n 721:\t\t * For now, allow all permission change attempts by returning the\n 722:\t\t * attempted permissions.  This can 'return old' to actively\n 723:\t\t * refuse the permission change at a later time.\n 724:\t\t */\n 725:\t\treturn new;\n 726:\t}\n 727:\t\n 728:\t/*\n 729:\t * Lookup the page table entry for a virtual address in a specific pgd.\n"
}

							input: 14083
							output: 30
							thoughts: 1115

**Fuzzing Evaluation for the CPA Patch**

Okay, let's break this down. My goal is to determine if this patch, specifically concerning `arch/x86/mm/pat/set_memory.c`, warrants fuzzing. This is a core subsystem related to x86 Memory Management and Change Page Attributes (CPA), so my initial instinct is to give it a close look.

First, the core triage philosophy needs to be considered. The primary goal of fuzzing is to unearth crashes, regressions, or newly exposed bugs, particularly those introduced by the patch. The key here is *reachability* – can the code actually execute in a standard virtualized environment like GCE or QEMU, or via emulated devices? The documentation stresses not trusting "no functional change" or refactoring claims blindly, and that new/modified assertions *must* be fuzzed if they're in reachable code. That's a strong indicator.

Now let's consider the negative criteria. The patch would be ignored if the code modified is *strictly* non-kernel and non-executable, decorative logging, structurally unreachable hardware, or unreachable execution paths. That last point – unreachable execution paths – is important. Driver teardown callbacks only used during hot-unplug, or code specific to other architectures are out.

Then, there are the positive criteria. We *definitely* want to fuzz if the patch touches reachable executable code. This includes any modifications in memory management, locking, BPF, the scheduler, core networking, VFS, or syscall handling. Refactoring reachable data structures or algorithm flows is also a trigger. Finally, and this is crucial, the introduction or modification of assertions (WARN_ON*, etc.) in reachable code paths *mandates* fuzzing.

Now, let's analyze the patch itself. The change introduces an `if (!kernel_set_to_readonly)` condition within the `verify_rwx()` function. This affects how the "W^X violation" is handled. Previously, `WARN_ONCE` was always triggered. Now, if `kernel_set_to_readonly` is false, it logs a `pr_warn_once` message. The key is when is this `kernel_set_to_readonly` flag false?

Ah, right – `kernel_set_to_readonly` is zero *during boot*, *before* `mark_rodata_ro()` is called. This is important: it's also zero when the kernel is booted with `rodata=off`. Syzkaller might boot with `rodata=off`, which means this new branch could be frequently taken during fuzzing. CPA (Change Page Attribute) is called at runtime when modules are loaded/unloaded, BPF JIT allocates/frees executable memory, and set_memory_ro/rw/x/nx/uc/wb is called via various drivers and subsystems. This suggests the code is *absolutely* reachable.

To be certain, I'm going to quickly check who calls CPA functions at runtime. I need to grep the kernel for callers of `change_page_attr` or `set_memory_` to confirm reachability.

Based on this, my preliminary evaluation is *yes*, this patch *does* warrant fuzzing. The change introduces a new code path that's likely reachable, especially with `rodata=off`, and involves a potentially important change in behavior. This definitely has the potential to expose latent bugs or trigger new assertions, so I would flag this for the fuzzing queue.

{
  "Expression": "set_memory_",
  "PathPrefix": "arch/x86/"
}

{
  "Output": "\nFull output is too long, showing 500 out of 761 lines.\nUse more precise expression if possible.\n\narch/x86/boot/startup/exports.h=6=PROVIDE(early_set_pages_state\t\t= __pi_early_set_pages_state);\narch/x86/boot/startup/exports.h:7:PROVIDE(early_snp_set_memory_private\t= __pi_early_snp_set_memory_private);\narch/x86/boot/startup/exports.h:8:PROVIDE(early_snp_set_memory_shared\t= __pi_early_snp_set_memory_shared);\narch/x86/boot/startup/exports.h-9-PROVIDE(get_hv_features\t\t\t= __pi_get_hv_features);\n--\narch/x86/boot/startup/map_kernel.c=33=static unsigned long __init sme_postprocess_startup(struct boot_params *bp,\n--\narch/x86/boot/startup/map_kernel.c-59-\t\t\t * mapping (kernel .text). PVALIDATE, by way of\narch/x86/boot/startup/map_kernel.c:60:\t\t\t * early_snp_set_memory_shared(), requires a valid virtual\narch/x86/boot/startup/map_kernel.c-61-\t\t\t * address but the kernel is currently running off of the identity\n--\narch/x86/boot/startup/map_kernel.c-63-\t\t\t */\narch/x86/boot/startup/map_kernel.c:64:\t\t\tearly_snp_set_memory_shared(paddr, paddr, PTRS_PER_PMD);\narch/x86/boot/startup/map_kernel.c-65-\n--\narch/x86/boot/startup/sev-startup.c=49=early_set_pages_state(unsigned long vaddr, unsigned long paddr,\n--\narch/x86/boot/startup/sev-startup.c-66-\narch/x86/boot/startup/sev-startup.c:67:void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,\narch/x86/boot/startup/sev-startup.c-68-\t\t\t\t\t unsigned long npages)\n--\narch/x86/boot/startup/sev-startup.c-91-\narch/x86/boot/startup/sev-startup.c:92:void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,\narch/x86/boot/startup/sev-startup.c-93-\t\t\t\t\tunsigned long npages)\n--\narch/x86/coco/sev/core.c=387=static void set_pages_state(unsigned long vaddr, unsigned long npages, int op)\n--\narch/x86/coco/sev/core.c-405-\narch/x86/coco/sev/core.c:406:void snp_set_memory_shared(unsigned long vaddr, unsigned long npages)\narch/x86/coco/sev/core.c-407-{\n--\narch/x86/coco/sev/core.c-413-\narch/x86/coco/sev/core.c:414:void snp_set_memory_private(unsigned long vaddr, unsigned long npages)\narch/x86/coco/sev/core.c-415-{\n--\narch/x86/coco/sev/core.c=544=static void unshare_all_memory(void)\n--\narch/x86/coco/sev/core.c-585-\t\t\tset_pte_enc(pte, level, (void *)addr);\narch/x86/coco/sev/core.c:586:\t\t\tsnp_set_memory_private(addr, npages);\narch/x86/coco/sev/core.c-587-\t\t}\n--\narch/x86/coco/sev/core.c-603-\taddr = (unsigned long)__start_bss_decrypted;\narch/x86/coco/sev/core.c:604:\tsnp_set_memory_private(addr, npages);\narch/x86/coco/sev/core.c-605-\n--\narch/x86/coco/sev/core.c=610=void snp_kexec_begin(void)\n--\narch/x86/coco/sev/core.c-623-\t */\narch/x86/coco/sev/core.c:624:\tif (!set_memory_enc_stop_conversion())\narch/x86/coco/sev/core.c-625-\t\tpr_warn(\"Failed to stop shared\u003c-\u003eprivate conversions\\n\");\n--\narch/x86/coco/sev/core.c=687=void snp_kexec_finish(void)\n--\narch/x86/coco/sev/core.c-721-\t\tset_pte_enc(pte, level, (void *)addr);\narch/x86/coco/sev/core.c:722:\t\tsnp_set_memory_private(addr, (size / PAGE_SIZE));\narch/x86/coco/sev/core.c-723-\t}\n--\narch/x86/coco/sev/core.c=1208=static void __init init_ghcb(int cpu)\n--\narch/x86/coco/sev/core.c-1214-\narch/x86/coco/sev/core.c:1215:\terr = early_set_memory_decrypted((unsigned long)\u0026data-\u003eghcb_page,\narch/x86/coco/sev/core.c-1216-\t\t\t\t\t sizeof(data-\u003eghcb_page));\n--\narch/x86/coco/sev/core.c=1473=static void free_shared_pages(void *buf, size_t sz)\n--\narch/x86/coco/sev/core.c-1480-\narch/x86/coco/sev/core.c:1481:\tret = set_memory_encrypted((unsigned long)buf, npages);\narch/x86/coco/sev/core.c-1482-\tif (ret) {\n--\narch/x86/coco/sev/core.c=1490=static void *alloc_shared_pages(size_t sz)\n--\narch/x86/coco/sev/core.c-1499-\narch/x86/coco/sev/core.c:1500:\tret = set_memory_decrypted((unsigned long)page_address(page), npages);\narch/x86/coco/sev/core.c-1501-\tif (ret) {\n--\narch/x86/coco/tdx/tdx.c=1010=static void tdx_kexec_begin(void)\n--\narch/x86/coco/tdx/tdx.c-1020-\t */\narch/x86/coco/tdx/tdx.c:1021:\tif (!set_memory_enc_stop_conversion())\narch/x86/coco/tdx/tdx.c-1022-\t\tpr_warn(\"Failed to stop shared\u003c-\u003eprivate conversions\\n\");\n--\narch/x86/hyperv/hv_init.c=118=static int hv_cpu_init(unsigned int cpu)\n--\narch/x86/hyperv/hv_init.c-158-\t\t\tif (*hvp \u0026\u0026 !ms_hyperv.paravisor_present \u0026\u0026 hv_isolation_type_snp()) {\narch/x86/hyperv/hv_init.c:159:\t\t\t\tWARN_ON_ONCE(set_memory_decrypted((unsigned long)(*hvp), 1));\narch/x86/hyperv/hv_init.c-160-\t\t\t\tmemset(*hvp, 0, PAGE_SIZE);\n--\narch/x86/hyperv/ivm.c=617=static void hv_vtom_kexec_begin(void)\n--\narch/x86/hyperv/ivm.c-627-\t */\narch/x86/hyperv/ivm.c:628:\tif (!set_memory_enc_stop_conversion())\narch/x86/hyperv/ivm.c-629-\t\tpr_warn(\"Failed to stop shared\u003c-\u003eprivate conversions\\n\");\n--\narch/x86/hyperv/ivm.c=677=static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],\n--\narch/x86/hyperv/ivm.c-737- * When transitioning memory between encrypted and decrypted, the caller\narch/x86/hyperv/ivm.c:738: * of set_memory_encrypted() or set_memory_decrypted() is responsible for\narch/x86/hyperv/ivm.c-739- * ensuring that the memory isn't in use and isn't referenced while the\n--\narch/x86/hyperv/ivm.c=756=static int hv_vtom_clear_present(unsigned long kbuffer, int pagecount, bool enc)\narch/x86/hyperv/ivm.c-757-{\narch/x86/hyperv/ivm.c:758:\treturn set_memory_np(kbuffer, pagecount);\narch/x86/hyperv/ivm.c-759-}\n--\narch/x86/hyperv/ivm.c=769=static int hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)\n--\narch/x86/hyperv/ivm.c-781-\t\tret = -ENOMEM;\narch/x86/hyperv/ivm.c:782:\t\tgoto err_set_memory_p;\narch/x86/hyperv/ivm.c-783-\t}\n--\narch/x86/hyperv/ivm.c-808-\narch/x86/hyperv/ivm.c:809:err_set_memory_p:\narch/x86/hyperv/ivm.c-810-\t/*\n--\narch/x86/hyperv/ivm.c-815-\t */\narch/x86/hyperv/ivm.c:816:\terr = set_memory_p(kbuffer, pagecount);\narch/x86/hyperv/ivm.c-817-\tif (err \u0026\u0026 !ret)\n--\narch/x86/include/asm/efi.h=238=static inline u32 efi64_convert_status(efi_status_t status)\n--\narch/x86/include/asm/efi.h-298-\narch/x86/include/asm/efi.h:299:#define __efi64_argmap_set_memory_space_attributes(phys, size, flags) \\\narch/x86/include/asm/efi.h-300-\t(__efi64_split(phys), __efi64_split(size), __efi64_split(flags))\n--\narch/x86/include/asm/efi.h-316-\narch/x86/include/asm/efi.h:317:#define __efi64_argmap_set_memory_attributes(protocol, phys, size, flags) \\\narch/x86/include/asm/efi.h-318-\t((protocol), __efi64_split(phys), __efi64_split(size), __efi64_split(flags))\n--\narch/x86/include/asm/kfence.h=22=static inline bool arch_kfence_init_pool(void)\n--\narch/x86/include/asm/kfence.h-33-\t\tif (level != PG_LEVEL_4K)\narch/x86/include/asm/kfence.h:34:\t\t\tset_memory_4k(addr, 1);\narch/x86/include/asm/kfence.h-35-\t}\n--\narch/x86/include/asm/mem_encrypt.h=51=void sme_enable(struct boot_params *bp);\narch/x86/include/asm/mem_encrypt.h-52-\narch/x86/include/asm/mem_encrypt.h:53:int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size);\narch/x86/include/asm/mem_encrypt.h:54:int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size);\narch/x86/include/asm/mem_encrypt.h-55-void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr,\n--\narch/x86/include/asm/mem_encrypt.h=89=static inline int __init\narch/x86/include/asm/mem_encrypt.h:90:early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; }\narch/x86/include/asm/mem_encrypt.h-91-static inline int __init\narch/x86/include/asm/mem_encrypt.h:92:early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0; }\narch/x86/include/asm/mem_encrypt.h-93-static inline void __init\n--\narch/x86/include/asm/set_memory.h-8-\narch/x86/include/asm/set_memory.h:9:#define set_memory_rox set_memory_rox\narch/x86/include/asm/set_memory.h:10:int set_memory_rox(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h-11-\narch/x86/include/asm/set_memory.h-12-/*\narch/x86/include/asm/set_memory.h:13: * The set_memory_* API can be used to change various attributes of a virtual\narch/x86/include/asm/set_memory.h-14- * address range. The attributes include:\n--\narch/x86/include/asm/set_memory.h-40-\narch/x86/include/asm/set_memory.h:41:int _set_memory_uc(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:42:int _set_memory_wc(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:43:int _set_memory_wt(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:44:int _set_memory_wb(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:45:int set_memory_uc(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:46:int set_memory_wc(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:47:int set_memory_wb(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:48:int set_memory_np(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:49:int set_memory_p(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:50:int set_memory_4k(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h-51-\narch/x86/include/asm/set_memory.h:52:bool set_memory_enc_stop_conversion(void);\narch/x86/include/asm/set_memory.h:53:int set_memory_encrypted(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:54:int set_memory_decrypted(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h-55-\narch/x86/include/asm/set_memory.h:56:int set_memory_np_noalias(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:57:int set_memory_nonglobal(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h:58:int set_memory_global(unsigned long addr, int numpages);\narch/x86/include/asm/set_memory.h-59-\n--\narch/x86/include/asm/set_memory.h=62=int set_pages_array_wb(struct page **pages, int addrinarray);\n--\narch/x86/include/asm/set_memory.h-68- * memory that the struct page represents, and internally just\narch/x86/include/asm/set_memory.h:69: * call the set_memory_* function. See the description of the\narch/x86/include/asm/set_memory.h:70: * set_memory_* function for more details on conventions.\narch/x86/include/asm/set_memory.h-71- *\n--\narch/x86/include/asm/set_memory.h-79- * get a struct page* that the old API required.\narch/x86/include/asm/set_memory.h:80: * To convert these cases, use set_memory_*() on the original\narch/x86/include/asm/set_memory.h-81- * virtual address, do not use these functions.\n--\narch/x86/include/asm/sev.h=505=void snp_register_ghcb_early(unsigned long paddr);\narch/x86/include/asm/sev.h:506:void early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,\narch/x86/include/asm/sev.h-507-\t\t\t\t  unsigned long npages);\narch/x86/include/asm/sev.h:508:void early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,\narch/x86/include/asm/sev.h-509-\t\t\t\t unsigned long npages);\narch/x86/include/asm/sev.h:510:void snp_set_memory_shared(unsigned long vaddr, unsigned long npages);\narch/x86/include/asm/sev.h:511:void snp_set_memory_private(unsigned long vaddr, unsigned long npages);\narch/x86/include/asm/sev.h-512-void snp_set_wakeup_secondary_cpu(void);\n--\narch/x86/include/asm/sev.h=612=static inline void __init\narch/x86/include/asm/sev.h:613:early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, unsigned long npages) { }\narch/x86/include/asm/sev.h-614-static inline void __init\narch/x86/include/asm/sev.h:615:early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, unsigned long npages) { }\narch/x86/include/asm/sev.h:616:static inline void snp_set_memory_shared(unsigned long vaddr, unsigned long npages) { }\narch/x86/include/asm/sev.h:617:static inline void snp_set_memory_private(unsigned long vaddr, unsigned long npages) { }\narch/x86/include/asm/sev.h-618-static inline void snp_set_wakeup_secondary_cpu(void) { }\n--\narch/x86/include/asm/vga.h-24-\tif (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))\t\t\t\\\narch/x86/include/asm/vga.h:25:\t\tset_memory_decrypted(start, (s) \u003e\u003e PAGE_SHIFT);\t\\\narch/x86/include/asm/vga.h-26-\t\t\t\t\t\t\t\t\\\n--\narch/x86/kernel/alternative.c=218=static void *its_alloc(void)\n--\narch/x86/kernel/alternative.c-232-\tif (pages == \u0026its_pages)\narch/x86/kernel/alternative.c:233:\t\tset_memory_x((unsigned long)page, 1);\narch/x86/kernel/alternative.c-234-\n--\narch/x86/kernel/amd_gart_64.c=619=static __init int init_amd_gatt(struct agp_kern_info *info)\n--\narch/x86/kernel/amd_gart_64.c-654-\t\tpanic(\"Cannot allocate GATT table\");\narch/x86/kernel/amd_gart_64.c:655:\tif (set_memory_uc((unsigned long)gatt, gatt_size \u003e\u003e PAGE_SHIFT))\narch/x86/kernel/amd_gart_64.c-656-\t\tpanic(\"Could not set GART PTEs to uncacheable pages\");\n--\narch/x86/kernel/amd_gart_64.c=714=int __init gart_iommu_init(void)\n--\narch/x86/kernel/amd_gart_64.c-781-\t */\narch/x86/kernel/amd_gart_64.c:782:\tset_memory_np((unsigned long)__va(iommu_bus_base),\narch/x86/kernel/amd_gart_64.c-783-\t\t\t\tiommu_size \u003e\u003e PAGE_SHIFT);\n--\narch/x86/kernel/apic/x2apic_uv_x.c=559=static __init void set_block_size(void)\n--\narch/x86/kernel/apic/x2apic_uv_x.c-564-\t\t/* adjust for ffs return of 1..64 */\narch/x86/kernel/apic/x2apic_uv_x.c:565:\t\tset_memory_block_size_order(order - 1);\narch/x86/kernel/apic/x2apic_uv_x.c-566-\t\tpr_info(\"UV: mem_block_size set to 0x%lx\\n\", mem_block_size);\n--\narch/x86/kernel/apic/x2apic_uv_x.c-569-\t\tpr_err(\"UV: mem_block_size error with 0x%lx\\n\", mem_block_size);\narch/x86/kernel/apic/x2apic_uv_x.c:570:\t\tset_memory_block_size_order(31);\narch/x86/kernel/apic/x2apic_uv_x.c-571-\t}\n--\narch/x86/kernel/cpu/common.c=2588=void __init arch_cpu_finalize_init(void)\n--\narch/x86/kernel/cpu/common.c-2663-\t\tif (!direct_gbpages)\narch/x86/kernel/cpu/common.c:2664:\t\t\tset_memory_4k((unsigned long)__va(0), 1);\narch/x86/kernel/cpu/common.c-2665-\t} else {\n--\narch/x86/kernel/ftrace.c=309=create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)\n--\narch/x86/kernel/ftrace.c-427-\narch/x86/kernel/ftrace.c:428:\tset_memory_rox((unsigned long)trampoline, npages);\narch/x86/kernel/ftrace.c-429-\treturn (unsigned long)trampoline;\n--\narch/x86/kernel/ftrace.c=435=void set_ftrace_ops_ro(void)\n--\narch/x86/kernel/ftrace.c-456-\t\tnpages = DIV_ROUND_UP(size, PAGE_SIZE);\narch/x86/kernel/ftrace.c:457:\t\tset_memory_ro((unsigned long)ops-\u003etrampoline, npages);\narch/x86/kernel/ftrace.c-458-\t} while_for_each_ftrace_op(ops);\n--\narch/x86/kernel/idt.c=294=void __init idt_setup_apic_and_irq_gates(void)\n--\narch/x86/kernel/idt.c-321-\t/* Make the IDT table read only */\narch/x86/kernel/idt.c:322:\tset_memory_ro((unsigned long)\u0026idt_table, 1);\narch/x86/kernel/idt.c-323-\n--\narch/x86/kernel/kvm.c=432=static inline __init void __set_percpu_decrypted(void *ptr, unsigned long size)\narch/x86/kernel/kvm.c-433-{\narch/x86/kernel/kvm.c:434:\tearly_set_memory_decrypted((unsigned long) ptr, size);\narch/x86/kernel/kvm.c-435-}\n--\narch/x86/kernel/kvmclock.c=225=static void __init kvmclock_init_mem(void)\n--\narch/x86/kernel/kvmclock.c-250-\tif (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {\narch/x86/kernel/kvmclock.c:251:\t\tr = set_memory_decrypted((unsigned long) hvclock_mem,\narch/x86/kernel/kvmclock.c-252-\t\t\t\t\t 1UL \u003c\u003c order);\n--\narch/x86/kernel/kvmclock.c-255-\t\t\thvclock_mem = NULL;\narch/x86/kernel/kvmclock.c:256:\t\t\tpr_warn(\"kvmclock: set_memory_decrypted() failed. Disabling\\n\");\narch/x86/kernel/kvmclock.c-257-\t\t\treturn;\n--\narch/x86/kernel/machine_kexec_32.c=135=int machine_kexec_prepare(struct kimage *image)\n--\narch/x86/kernel/machine_kexec_32.c-138-\narch/x86/kernel/machine_kexec_32.c:139:\tset_memory_x((unsigned long)page_address(image-\u003econtrol_code_page), 1);\narch/x86/kernel/machine_kexec_32.c-140-\terror = machine_kexec_alloc_page_tables(image);\n--\narch/x86/kernel/machine_kexec_32.c=151=void machine_kexec_cleanup(struct kimage *image)\narch/x86/kernel/machine_kexec_32.c-152-{\narch/x86/kernel/machine_kexec_32.c:153:\tset_memory_nx((unsigned long)page_address(image-\u003econtrol_code_page), 1);\narch/x86/kernel/machine_kexec_32.c-154-\tmachine_kexec_free_page_tables(image);\n--\narch/x86/kernel/machine_kexec_64.c=343=int machine_kexec_prepare(struct kimage *image)\n--\narch/x86/kernel/machine_kexec_64.c-364-\narch/x86/kernel/machine_kexec_64.c:365:\tset_memory_rox((unsigned long)control_page, 1);\narch/x86/kernel/machine_kexec_64.c-366-\n--\narch/x86/kernel/machine_kexec_64.c=370=void machine_kexec_cleanup(struct kimage *image)\n--\narch/x86/kernel/machine_kexec_64.c-373-\narch/x86/kernel/machine_kexec_64.c:374:\tset_memory_nx((unsigned long)control_page, 1);\narch/x86/kernel/machine_kexec_64.c:375:\tset_memory_rw((unsigned long)control_page, 1);\narch/x86/kernel/machine_kexec_64.c-376-\n--\narch/x86/kernel/machine_kexec_64.c=648=static void kexec_mark_dm_crypt_keys(bool protect)\n--\narch/x86/kernel/machine_kexec_64.c-657-\t\tif (protect)\narch/x86/kernel/machine_kexec_64.c:658:\t\t\tset_memory_np((unsigned long)phys_to_virt(start_paddr), nr_pages);\narch/x86/kernel/machine_kexec_64.c-659-\t\telse\narch/x86/kernel/machine_kexec_64.c:660:\t\t\tset_memory_p((unsigned long)phys_to_virt(start_paddr), nr_pages);\narch/x86/kernel/machine_kexec_64.c-661-\t}\n--\narch/x86/kernel/machine_kexec_64.c=686=int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)\n--\narch/x86/kernel/machine_kexec_64.c-695-\t */\narch/x86/kernel/machine_kexec_64.c:696:\treturn set_memory_decrypted((unsigned long)vaddr, pages);\narch/x86/kernel/machine_kexec_64.c-697-}\n--\narch/x86/kernel/machine_kexec_64.c=699=void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)\n--\narch/x86/kernel/machine_kexec_64.c-707-\t */\narch/x86/kernel/machine_kexec_64.c:708:\tset_memory_encrypted((unsigned long)vaddr, pages);\narch/x86/kernel/machine_kexec_64.c-709-}\n--\narch/x86/kvm/lapic.c=2910=int kvm_alloc_apic_access_page(struct kvm *kvm)\n--\narch/x86/kvm/lapic.c-2919-\narch/x86/kvm/lapic.c:2920:\thva = __x86_set_memory_region(kvm, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,\narch/x86/kvm/lapic.c-2921-\t\t\t\t      APIC_DEFAULT_PHYS_BASE, PAGE_SIZE);\n--\narch/x86/kvm/lapic.c=2931=void kvm_inhibit_apic_access_page(struct kvm_vcpu *vcpu)\n--\narch/x86/kvm/lapic.c-2942-\tif (kvm-\u003earch.apic_access_memslot_enabled) {\narch/x86/kvm/lapic.c:2943:\t\t__x86_set_memory_region(kvm, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT, 0, 0);\narch/x86/kvm/lapic.c-2944-\t\t/*\n--\narch/x86/kvm/mmu/mmu.c=6801=static void free_mmu_pages(struct kvm_mmu *mmu)\n--\narch/x86/kvm/mmu/mmu.c-6803-\tif (!tdp_enabled \u0026\u0026 mmu-\u003epae_root)\narch/x86/kvm/mmu/mmu.c:6804:\t\tset_memory_encrypted((unsigned long)mmu-\u003epae_root, 1);\narch/x86/kvm/mmu/mmu.c-6805-\tfree_page((unsigned long)mmu-\u003epae_root);\n--\narch/x86/kvm/mmu/mmu.c=6810=static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, struct kvm_pagewalk *w)\n--\narch/x86/kvm/mmu/mmu.c-6854-\tif (!tdp_enabled)\narch/x86/kvm/mmu/mmu.c:6855:\t\tset_memory_decrypted((unsigned long)mmu-\u003epae_root, 1);\narch/x86/kvm/mmu/mmu.c-6856-\telse\n--\narch/x86/kvm/mmu/mmu.c=8113=static void hugepage_set_mixed(struct kvm_memory_slot *slot, gfn_t gfn,\n--\narch/x86/kvm/mmu/mmu.c-8118-\narch/x86/kvm/mmu/mmu.c:8119:bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,\narch/x86/kvm/mmu/mmu.c-8120-\t\t\t\t\tstruct kvm_gfn_range *range)\n--\narch/x86/kvm/mmu/mmu.c=8182=static bool hugepage_has_attrs(struct kvm *kvm, struct kvm_memory_slot *slot,\n--\narch/x86/kvm/mmu/mmu.c-8198-\narch/x86/kvm/mmu/mmu.c:8199:bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,\narch/x86/kvm/mmu/mmu.c-8200-\t\t\t\t\t struct kvm_gfn_range *range)\n--\narch/x86/kvm/vmx/vmx.c=4029=static int init_rmode_identity_map(struct kvm *kvm)\n--\narch/x86/kvm/vmx/vmx.c-4044-\narch/x86/kvm/vmx/vmx.c:4045:\tuaddr = __x86_set_memory_region(kvm,\narch/x86/kvm/vmx/vmx.c-4046-\t\t\t\t\tIDENTITY_PAGETABLE_PRIVATE_MEMSLOT,\n--\narch/x86/kvm/vmx/vmx.c=5276=int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr)\n--\narch/x86/kvm/vmx/vmx.c-5283-\tmutex_lock(\u0026kvm-\u003eslots_lock);\narch/x86/kvm/vmx/vmx.c:5284:\tret = __x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, addr,\narch/x86/kvm/vmx/vmx.c-5285-\t\t\t\t      PAGE_SIZE * 3);\n--\narch/x86/kvm/x86.c=9843=int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)\n--\narch/x86/kvm/x86.c-9916-/**\narch/x86/kvm/x86.c:9917: * __x86_set_memory_region: Setup KVM internal memory slot\narch/x86/kvm/x86.c-9918- *\n--\narch/x86/kvm/x86.c-9937- */\narch/x86/kvm/x86.c:9938:void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa,\narch/x86/kvm/x86.c-9939-\t\t\t\t      u32 size)\n--\narch/x86/kvm/x86.c-9989-}\narch/x86/kvm/x86.c:9990:EXPORT_SYMBOL_FOR_KVM_INTERNAL(__x86_set_memory_region);\narch/x86/kvm/x86.c-9991-\n--\narch/x86/kvm/x86.c=10014=void kvm_arch_destroy_vm(struct kvm *kvm)\n--\narch/x86/kvm/x86.c-10022-\t\tmutex_lock(\u0026kvm-\u003eslots_lock);\narch/x86/kvm/x86.c:10023:\t\t__x86_set_memory_region(kvm, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,\narch/x86/kvm/x86.c-10024-\t\t\t\t\t0, 0);\narch/x86/kvm/x86.c:10025:\t\t__x86_set_memory_region(kvm, IDENTITY_PAGETABLE_PRIVATE_MEMSLOT,\narch/x86/kvm/x86.c-10026-\t\t\t\t\t0, 0);\narch/x86/kvm/x86.c:10027:\t\t__x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, 0, 0);\narch/x86/kvm/x86.c-10028-\t\tmutex_unlock(\u0026kvm-\u003eslots_lock);\n--\narch/x86/kvm/x86.c=10093=static int kvm_alloc_memslot_metadata(struct kvm *kvm,\n--\narch/x86/kvm/x86.c-10100-\t * Clear out the previous array pointers for the KVM_MR_MOVE case.  The\narch/x86/kvm/x86.c:10101:\t * old arrays will be freed by kvm_set_memory_region() if installing\narch/x86/kvm/x86.c-10102-\t * the new memslot is successful.\n--\narch/x86/kvm/x86.h=526=int kvm_get_nr_pending_nmis(struct kvm_vcpu *vcpu);\narch/x86/kvm/x86.h-527-\narch/x86/kvm/x86.h:528:void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa,\narch/x86/kvm/x86.h-529-\t\t\t\t     u32 size);\n--\narch/x86/mm/init.c=897=void free_init_pages(const char *what, unsigned long begin, unsigned long end)\n--\narch/x86/mm/init.c-925-\t\tkmemleak_free_part((void *)begin, end - begin);\narch/x86/mm/init.c:926:\t\tset_memory_np(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c-927-\t} else {\n--\narch/x86/mm/init.c-932-\t\t */\narch/x86/mm/init.c:933:\t\tset_memory_nx(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c:934:\t\tset_memory_rw(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c-935-\n--\narch/x86/mm/init.c=946=void free_kernel_image_pages(const char *what, void *begin, void *end)\n--\narch/x86/mm/init.c-969-\tif (IS_ENABLED(CONFIG_X86_64) \u0026\u0026 cpu_feature_enabled(X86_FEATURE_PTI))\narch/x86/mm/init.c:970:\t\tset_memory_np_noalias(begin_ul, len_pages);\narch/x86/mm/init.c-971-}\n--\narch/x86/mm/init_32.c=723=static void mark_nxdata_nx(void)\n--\narch/x86/mm/init_32.c-736-\t\tprintk(KERN_INFO \"NX-protecting the kernel data: %luk\\n\", size \u003e\u003e 10);\narch/x86/mm/init_32.c:737:\tset_memory_nx(start, size \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_32.c-738-}\n--\narch/x86/mm/init_64.c=1359=void mark_rodata_ro(void)\n--\narch/x86/mm/init_64.c-1369-\t       (end - start) \u003e\u003e 10);\narch/x86/mm/init_64.c:1370:\tset_memory_ro(start, (end - start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1371-\n--\narch/x86/mm/init_64.c-1386-\tall_end = roundup((unsigned long)_brk_end, PMD_SIZE);\narch/x86/mm/init_64.c:1387:\tset_memory_nx(text_end, (all_end - text_end) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1388-\n--\narch/x86/mm/init_64.c-1392-\tprintk(KERN_INFO \"Testing CPA: undo %lx-%lx\\n\", start, end);\narch/x86/mm/init_64.c:1393:\tset_memory_rw(start, (end-start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1394-\narch/x86/mm/init_64.c-1395-\tprintk(KERN_INFO \"Testing CPA: again\\n\");\narch/x86/mm/init_64.c:1396:\tset_memory_ro(start, (end-start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1397-#endif\n--\narch/x86/mm/init_64.c-1415-/* Adjustable memory block size */\narch/x86/mm/init_64.c:1416:static unsigned long set_memory_block_size;\narch/x86/mm/init_64.c:1417:int __init set_memory_block_size_order(unsigned int order)\narch/x86/mm/init_64.c-1418-{\n--\narch/x86/mm/init_64.c-1423-\narch/x86/mm/init_64.c:1424:\tset_memory_block_size = size;\narch/x86/mm/init_64.c-1425-\treturn 0;\n--\narch/x86/mm/init_64.c=1428=static unsigned long probe_memory_block_size(void)\n--\narch/x86/mm/init_64.c-1433-\t/* If memory block size has been set, then use it */\narch/x86/mm/init_64.c:1434:\tbz = set_memory_block_size;\narch/x86/mm/init_64.c-1435-\tif (bz)\n--\narch/x86/mm/ioremap.c=45=int ioremap_change_attr(unsigned long vaddr, unsigned long size,\n--\narch/x86/mm/ioremap.c-53-\tdefault:\narch/x86/mm/ioremap.c:54:\t\terr = _set_memory_uc(vaddr, nrpages);\narch/x86/mm/ioremap.c-55-\t\tbreak;\narch/x86/mm/ioremap.c-56-\tcase _PAGE_CACHE_MODE_WC:\narch/x86/mm/ioremap.c:57:\t\terr = _set_memory_wc(vaddr, nrpages);\narch/x86/mm/ioremap.c-58-\t\tbreak;\narch/x86/mm/ioremap.c-59-\tcase _PAGE_CACHE_MODE_WT:\narch/x86/mm/ioremap.c:60:\t\terr = _set_memory_wt(vaddr, nrpages);\narch/x86/mm/ioremap.c-61-\t\tbreak;\narch/x86/mm/ioremap.c-62-\tcase _PAGE_CACHE_MODE_WB:\narch/x86/mm/ioremap.c:63:\t\terr = _set_memory_wb(vaddr, nrpages);\narch/x86/mm/ioremap.c-64-\t\tbreak;\n--\narch/x86/mm/mem_encrypt_amd.c=57=static inline void __init snp_memcpy(void *dst, void *src, size_t sz,\n--\narch/x86/mm/mem_encrypt_amd.c-66-\t\t */\narch/x86/mm/mem_encrypt_amd.c:67:\t\tearly_snp_set_memory_shared((unsigned long)__va(paddr), paddr, npages);\narch/x86/mm/mem_encrypt_amd.c-68-\n--\narch/x86/mm/mem_encrypt_amd.c-71-\t\t/* Restore the page state after the memcpy. */\narch/x86/mm/mem_encrypt_amd.c:72:\t\tearly_snp_set_memory_private((unsigned long)__va(paddr), paddr, npages);\narch/x86/mm/mem_encrypt_amd.c-73-\t} else {\n--\narch/x86/mm/mem_encrypt_amd.c=286=static int amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-292-\tif (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) \u0026\u0026 !enc)\narch/x86/mm/mem_encrypt_amd.c:293:\t\tsnp_set_memory_shared(vaddr, npages);\narch/x86/mm/mem_encrypt_amd.c-294-\n--\narch/x86/mm/mem_encrypt_amd.c=299=static int amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-305-\tif (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) \u0026\u0026 enc)\narch/x86/mm/mem_encrypt_amd.c:306:\t\tsnp_set_memory_private(vaddr, npages);\narch/x86/mm/mem_encrypt_amd.c-307-\n--\narch/x86/mm/mem_encrypt_amd.c=358=static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-378-\t\t */\narch/x86/mm/mem_encrypt_amd.c:379:\t\tearly_snp_set_memory_shared((unsigned long)__va(d.pa), d.pa, 1);\narch/x86/mm/mem_encrypt_amd.c-380-\t}\n--\narch/x86/mm/mem_encrypt_amd.c-388-\tif (enc)\n\n"
}

							input: 28343
							output: 21
							thoughts: 1378

**Analyzing W^X Violation Detection in set_memory.c**

Alright, let's break this down. My initial thought process is to understand the context of this `set_memory.c` file and, specifically, the functions like `set_memory_ro`, `set_memory_rw`, and others. Where are these functions called? I need to build a mental map of their usage.

I recall BPF JIT, ftrace, the module loader – they all manipulate memory permissions. My mind immediately jumps to the relevant functions: `module_enable_ro()`, `module_enable_nx()`, `bpf_jit_binary_lock_ro()`, and `bpf_prog_lock_ro()`. Kprobes also come to mind with `alloc_insn_page()` and its implications on setting read-only/read-write permissions. Let's not forget `/dev/mem` and `ioremap` which could be relevant too. I need to keep these in mind as potential call sites.

Now, to get into the nitty-gritty of the patch itself, I should examine the `git show` output to understand the changes. Let's see... the code introduces a warning about W^X violations within the `verify_rwx` function. I see the addition of a `pr_warn_once` call.

I carefully examine the `verify_rwx` function. It seems to check for changes that could violate the Write XOR Execute (W^X) principle. It has some conditions related to the architecture (32-bit specifically) and NX support. I can see the core logic of the W^X check, looking at the old and new page protection flags.

Aha! Now I see a crucial detail: there are two `pr_warn_once` calls in the code. One is conditional on `!kernel_set_to_readonly` and the other is unconditional. My attention is now drawn to the first argument of `pr_warn_once`. Is it a condition, or is it part of the format string? That's a classic gotcha! I need to be absolutely sure what that first argument is doing. Let's check the definition of `pr_warn_once`! I need to be certain about the logging behavior here.

{
  "Expression": "#define pr_warn_once"
}

{
  "Output": "include/linux/ceph/ceph_debug.h-59-\t\tclient-\u003emonc.auth-\u003eglobal_id, ##__VA_ARGS__)\ninclude/linux/ceph/ceph_debug.h:60:#define pr_warn_once_client(client, fmt, ...)\t\t\t\t\\\ninclude/linux/ceph/ceph_debug.h-61-\tpr_warn_once(\"[%pU %llu]: \" fmt, \u0026client-\u003efsid,\t\t\t\\\n--\ninclude/linux/printk.h=407=struct pi_entry {\n--\ninclude/linux/printk.h-667-\tprintk_once(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)\ninclude/linux/printk.h:668:#define pr_warn_once(fmt, ...)\t\t\t\t\t\\\ninclude/linux/printk.h-669-\tprintk_once(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)\n--\nsecurity/selinux/ss/policydb.h=417=extern u32 string_to_av_perm(struct policydb *p, u16 tclass, const char *name);\nsecurity/selinux/ss/policydb.h-418-\nsecurity/selinux/ss/policydb.h:419:#define pr_warn_once_policyload(policy, fmt, ...)    \\\nsecurity/selinux/ss/policydb.h-420-\tdo {                                         \\\n--\ntools/testing/vma/include/custom.h=12=extern unsigned long dac_mmap_min_addr;\n--\ntools/testing/vma/include/custom.h-23- */\ntools/testing/vma/include/custom.h:24:#define pr_warn_once pr_err\ntools/testing/vma/include/custom.h-25-\n"
}

							input: 30692
							output: 38
							thoughts: 803

**Kernel Bug Discovery: A Deep Dive**

Okay, here's what's going through my head as I analyze this: I'm staring at this `pr_warn_once(1, "CPA detected...")` and something instantly screams "wrong!" The function signature clearly indicates the first parameter should be the format string, not a numerical value. My immediate thought is, "Wait, `pr_warn_once(fmt, ...)` takes `fmt` first!", then I cross-reference this with `WARN_ONCE(condition, fmt, ...)` which takes the *condition* first. It's like deja vu.

In this specific patch, it's calling `pr_warn_once(1, "CPA detected W^X violation: %016llx -> ...", ...)` and the first argument *is* just the number `1` which is being interpreted as a pointer, specifically `(const char *)1`, or, essentially, NULL plus one! This is when the alarm bells go off.

When `pr_warn_once(1, ...)` is invoked, `fmt` is being set to `(char *)1`. That means, ultimately, we're trying to dereference the address `0x00000001`! This is going to cause a kernel oops, a page fault, because it's accessing an invalid memory location! HOLY COW, that's a serious bug! The author appears to have copied `WARN_ONCE(1, "...")` and simply changed `WARN_ONCE` to `pr_warn_once`, without removing the conditional `1`! They're passing `1` as a format string when it should be `"CPA detected..."`.

Essentially, if `!kernel_set_to_readonly` and `verify_rwx` detects a W^X violation, calling `pr_warn_once(1, ...)` passes integer 1 as pointer to format string into `printk_once` -> `vprintk_store` -> page fault! This is going to crash the kernel in the worst way.

Now I need to understand how reachable this actually is. When does `verify_rwx` get called when `!kernel_set_to_readonly`? The possibilities I can see are:

1.  Early boot before `mark_rodata_ro()` is called.
2.  When booting with `rodata=off` or if `CONFIG_STRICT_KERNEL_RWX` is disabled. In that case, `kernel_set_to_readonly` would remain 0.

If `rodata=off`, `kernel_set_to_readonly` stays 0 for the entire lifetime of the system!

At runtime, any BPF program load, module load, ftrace trampoline creation, kprobe, or any user-triggered syscall that changes page permissions can call `verify_rwx()`. If a W^X change is detected by `verify_rwx()` (e.g. setting RW on an executable page or X on a writable page), `!kernel_set_to_readonly` is true and it executes `pr_warn_once(1, ...)` which crashes the kernel because the format string is really `(char *)0x1`!

Let me make sure this checks out. What does `pr_warn_once` actually expand to? I need to check `include/linux/printk.h`:

```c
#define pr_warn_once(fmt, ...)					\
	printk_once(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
```

Wait, `pr_fmt(1)` becomes `1`. Then `printk_once(KERN_WARNING 1, ...)`... does this even compile? `KERN_WARNING` becomes `"\001" "4"` which compiles as string concatenation. But `KERN_WARNING 1` attempts to concatenate string with integer, which is undefined behavior! Why did it compile? I need to examine how `pr_fmt` is defined. I should look in `set_memory.c` or check `arch/x86/mm/pat/set_memory.c`.

{
  "Expression": "pr_fmt",
  "PathPrefix": "arch/x86/mm/pat/set_memory.c"
}

{
  "error": "no matches"
}

							input: 32447
							output: 20
							thoughts: 103

**Deconstructing the Warning Message**

Okay, let's break this down. I need to understand where this warning is originating, so I'm diving into the kernel code. First, I'm checking `arch/x86/mm/pat/set_memory.c`, thinking that's a likely spot for memory-related warnings. And, nope, no `pr_fmt(fmt)` macro defined there. Right, so, in *this* context, `pr_fmt(fmt)` is just resolving to `fmt`. Simple enough.

Then I see `pr_warn_once(1, ...)`. Expanding that, based on my understanding of how these macros work, leads me to `printk_once(KERN_WARNING 1, ...)`. Ah, `printk_once`. That's the key. Where is *that* defined? I need to check `include/linux/printk.h`. Gotta see the exact definition of `printk_once` to fully grasp what's happening. I need to know how the "once" aspect is implemented to understand the behavior of the warning.

{
  "Expression": "#define printk_once"
}

{
  "Output": "include/linux/printk.h=407=struct pi_entry {\n--\ninclude/linux/printk.h-648-#ifdef CONFIG_PRINTK\ninclude/linux/printk.h:649:#define printk_once(fmt, ...)\t\t\t\t\t\\\ninclude/linux/printk.h-650-\tDO_ONCE_LITE(printk, fmt, ##__VA_ARGS__)\n--\ninclude/linux/printk.h-653-#else\ninclude/linux/printk.h:654:#define printk_once(fmt, ...)\t\t\t\t\t\\\ninclude/linux/printk.h-655-\tno_printk(fmt, ##__VA_ARGS__)\n"
}

							input: 32975
							output: 32
							thoughts: 87

Okay, let's break this down.

**Investigating a Kernel Logging Issue**

Alright, first things first, I need to check out this `DO_ONCE_LITE` macro. It looks like it's being used with `printk`, which immediately flags something important. `DO_ONCE_LITE(printk, KERN_WARNING 1, ...)`...wait a second. That `KERN_WARNING 1` looks wrong. In standard C syntax, that's almost certainly a syntax error unless something funky is happening with how `KERN_WARNING` is defined. Something is making me think that it is not being properly prefixed.

Okay, let's pause and investigate `KERN_WARNING` to see what is going on. I know this is going to be in an include file. I'll need to check `include/linux/kern_levels.h` to see exactly how that is defined and what it is meant to represent.

{
  "Expression": "KERN_WARNING",
  "PathPrefix": "include/linux/kern_levels.h"
}

{
  "Output": "include/linux/kern_levels.h-11-#define KERN_ERR\tKERN_SOH \"3\"\t/* error conditions */\ninclude/linux/kern_levels.h:12:#define KERN_WARNING\tKERN_SOH \"4\"\t/* warning conditions */\ninclude/linux/kern_levels.h-13-#define KERN_NOTICE\tKERN_SOH \"5\"\t/* normal but significant condition */\n"
}

							input: 33407
							output: 41
							thoughts: 418

**My Assessment of the Potential Fuzzing Target**

Okay, so `KERN_WARNING` is defined as `"\001" "4"`. That immediately raises a red flag. `KERN_WARNING 1` expands to `"\001" "4" 1`, which is obviously a C compiler syntax error. This confirms my initial suspicion – the patch author either didn't test this properly, or a bug was introduced! This is a good sign, and it means we need to dig deeper.

The changes are within `arch/x86/mm/pat/set_memory.c`, which, as I know, is a critical part of the x86 memory management system (Change Page Attributes, or CPA).

Now, the important question: is this worth fuzzing? Let's break it down:

1.  **Core Subsystem:** `arch/x86/mm/pat/set_memory.c` is definitely a core subsystem, dealing directly with x86 memory management. Check.
2.  **Reachable:** Yes, CPA is reachable through a multitude of syscalls and kernel operations on amd64 systems. Things like BPF JIT, module loading/unloading, tracepoints/kprobes, and the `set_memory_*` callers, all can potentially trigger issues. Check.
3.  **Defensive Checks:** The patch modifies defensive checks and W^X violation verification logic in `verify_rwx()`. Check.

Considering the criteria from the instructions (Section 3), it looks like this is a strong candidate:
*   Memory management modifications are a go.
*   The modification is altering defensive checks in reachable paths.

Therefore, `WorthFuzzing` is definitively `true`.

Now let's determine the FocusSymbols.

I need to identify which symbols to focus on during fuzzing. I'll start by checking the functions in `arch/x86/mm/pat/set_memory.c` that are called or involved. It seems `arch/x86/mm/pat/set_memory.c` is the right place to look.

{
  "Expression": "^int set_memory_",
  "PathPrefix": "arch/x86/mm/pat/set_memory.c"
}

{
  "Output": "arch/x86/mm/pat/set_memory.c=2194=int _set_memory_uc(unsigned long addr, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2206-\narch/x86/mm/pat/set_memory.c:2207:int set_memory_uc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2208-{\n--\narch/x86/mm/pat/set_memory.c=2232=int _set_memory_wc(unsigned long addr, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2247-\narch/x86/mm/pat/set_memory.c:2248:int set_memory_wc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2249-{\n--\narch/x86/mm/pat/set_memory.c=2271=int _set_memory_wb(unsigned long addr, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2277-\narch/x86/mm/pat/set_memory.c:2278:int set_memory_wb(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2279-{\n--\narch/x86/mm/pat/set_memory.c=2329=EXPORT_SYMBOL_GPL(clear_mce_nospec);\n--\narch/x86/mm/pat/set_memory.c-2331-\narch/x86/mm/pat/set_memory.c:2332:int set_memory_x(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2333-{\n--\narch/x86/mm/pat/set_memory.c-2339-\narch/x86/mm/pat/set_memory.c:2340:int set_memory_nx(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2341-{\n--\narch/x86/mm/pat/set_memory.c-2347-\narch/x86/mm/pat/set_memory.c:2348:int set_memory_ro(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2349-{\n--\narch/x86/mm/pat/set_memory.c-2352-\narch/x86/mm/pat/set_memory.c:2353:int set_memory_rox(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2354-{\n--\narch/x86/mm/pat/set_memory.c-2363-\narch/x86/mm/pat/set_memory.c:2364:int set_memory_rw(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2365-{\n--\narch/x86/mm/pat/set_memory.c-2368-\narch/x86/mm/pat/set_memory.c:2369:int set_memory_np(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2370-{\n--\narch/x86/mm/pat/set_memory.c-2373-\narch/x86/mm/pat/set_memory.c:2374:int set_memory_np_noalias(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2375-{\n--\narch/x86/mm/pat/set_memory.c-2380-\narch/x86/mm/pat/set_memory.c:2381:int set_memory_p(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2382-{\n--\narch/x86/mm/pat/set_memory.c-2385-\narch/x86/mm/pat/set_memory.c:2386:int set_memory_4k(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2387-{\n--\narch/x86/mm/pat/set_memory.c-2392-\narch/x86/mm/pat/set_memory.c:2393:int set_memory_nonglobal(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2394-{\n--\narch/x86/mm/pat/set_memory.c-2398-\narch/x86/mm/pat/set_memory.c:2399:int set_memory_global(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2400-{\n--\narch/x86/mm/pat/set_memory.c=2495=static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)\n--\narch/x86/mm/pat/set_memory.c-2510-\narch/x86/mm/pat/set_memory.c:2511:int set_memory_encrypted(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2512-{\n--\narch/x86/mm/pat/set_memory.c=2515=EXPORT_SYMBOL_GPL(set_memory_encrypted);\narch/x86/mm/pat/set_memory.c-2516-\narch/x86/mm/pat/set_memory.c:2517:int set_memory_decrypted(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2518-{\n"
}

							input: 35907
							output: 44
							thoughts: 80

Here's my thought process, as if I were analyzing this code:

**Analyzing the Call Sites of `verify_rwx`**

Okay, so `verify_rwx` is a static inline function, which is a key piece of information.  I immediately note it's defined in `arch/x86/mm/pat/set_memory.c`. Now, I need to understand its usage within that file. The fact that it's inline suggests it's likely called a few times in strategically placed spots. My immediate priority is to understand where `verify_rwx` gets invoked. That will inform its purpose. I'll focus my search on `arch/x86/mm/pat/set_memory.c`, specifically around line numbers 1067 and 1882. I expect to see the calls there, which should give me the context I need. From there, I can determine the role of `verify_rwx` in the system.

{
  "File": "arch/x86/mm/pat/set_memory.c",
  "FirstLine": 1060,
  "LineCount": 30
}

{
  "Contents": "1060:\t\t/*\n1061:\t\t * Check whether the requested pgprot is conflicting with a static\n1062:\t\t * protection requirement in the large page.\n1063:\t\t */\n1064:\t\tnew_prot = static_protections(req_prot, lpaddr, old_pfn, numpages,\n1065:\t\t\t\t\t      psize, CPA_DETECT);\n1066:\t\n1067:\t\tnew_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages,\n1068:\t\t\t\t      nx, rw);\n1069:\t\n1070:\t\t/*\n1071:\t\t * If there is a conflict, split the large page.\n1072:\t\t *\n1073:\t\t * There used to be a 4k wise evaluation trying really hard to\n1074:\t\t * preserve the large pages, but experimentation has shown, that this\n1075:\t\t * does not help at all. There might be corner cases which would\n1076:\t\t * preserve one large page occasionally, but it's really not worth the\n1077:\t\t * extra code and cycles for the common case.\n1078:\t\t */\n1079:\t\tif (pgprot_val(req_prot) != pgprot_val(new_prot))\n1080:\t\t\treturn 1;\n1081:\t\n1082:\t\t/* All checks passed. Update the large page mapping. */\n1083:\t\tnew_pte = pfn_pte(old_pfn, new_prot);\n1084:\t\t__set_pmd_pte(kpte, address, new_pte);\n1085:\t\tcpa-\u003eflags |= CPA_FLUSHTLB;\n1086:\t\tcpa_inc_lp_preserved(level);\n1087:\t\treturn 0;\n1088:\t}\n1089:\t\n"
}

							input: 36734
							output: 44
							thoughts: 29

Okay, here's my interpretation of that thought as a first-person expert summary:

**Digging into Memory Attribute Table (PAT) Behavior**

Right, so we're looking at some memory management shenanigans, and the PAT is probably involved. My initial hunch is to take a look at `arch/x86/mm/pat/set_memory.c`, specifically line 1882. This strongly suggests that there's a specific set memory operation related to the PAT that I want to investigate, likely involving how memory attributes are being set. Given the complexity of the PAT and its impact on performance and caching, something on this line will probably give some good clues on what needs looking at. It's likely involved in updating the MTRR or PAT entries. This is where the magic happens, so checking this particular spot is crucial to understanding the underlying mechanism.

{
  "File": "arch/x86/mm/pat/set_memory.c",
  "FirstLine": 1870,
  "LineCount": 35
}

{
  "Contents": "1870:\t\t\tpgprot_t old_prot = pte_pgprot(old_pte);\n1871:\t\t\tpgprot_t new_prot = pte_pgprot(old_pte);\n1872:\t\t\tunsigned long pfn = pte_pfn(old_pte);\n1873:\t\n1874:\t\t\tpgprot_val(new_prot) \u0026= ~pgprot_val(cpa-\u003emask_clr);\n1875:\t\t\tpgprot_val(new_prot) |= pgprot_val(cpa-\u003emask_set);\n1876:\t\n1877:\t\t\tcpa_inc_4k_install();\n1878:\t\t\t/* Hand in lpsize = 0 to enforce the protection mechanism */\n1879:\t\t\tnew_prot = static_protections(new_prot, address, pfn, 1, 0,\n1880:\t\t\t\t\t\t      CPA_PROTECT);\n1881:\t\n1882:\t\t\tnew_prot = verify_rwx(old_prot, new_prot, address, pfn, 1,\n1883:\t\t\t\t\t      nx, rw);\n1884:\t\n1885:\t\t\tnew_prot = pgprot_clear_protnone_bits(new_prot);\n1886:\t\n1887:\t\t\t/*\n1888:\t\t\t * We need to keep the pfn from the existing PTE,\n1889:\t\t\t * after all we're only going to change its attributes\n1890:\t\t\t * not the memory it points to\n1891:\t\t\t */\n1892:\t\t\tnew_pte = pfn_pte(pfn, new_prot);\n1893:\t\t\tcpa-\u003epfn = pfn;\n1894:\t\t\t/*\n1895:\t\t\t * Do we really change anything ?\n1896:\t\t\t */\n1897:\t\t\tif (pte_val(old_pte) != pte_val(new_pte)) {\n1898:\t\t\t\tset_pte_atomic(kpte, new_pte);\n1899:\t\t\t\tcpa-\u003eflags |= CPA_FLUSHTLB;\n1900:\t\t\t}\n1901:\t\t\tcpa-\u003enumpages = 1;\n1902:\t\t\treturn 0;\n1903:\t\t}\n1904:\t\n"
}

							input: 37578
							output: 41
							thoughts: 57

Here's my take on the thought process, as requested:

**Digging into the Page Attribute Management**

Okay, so `verify_rwx()` pops up in two key places: `__should_split_large_page` and `__change_page_attr`. I need to figure out the interplay here, and the potential impact. It looks like it's guarding against something, likely a bad page state.

I need to understand what's *triggering* `__change_page_attr`. That function is crucial because it seems to be the place where permissions are actually getting modified. I should examine the call graph to that function to understand all of the use cases. Knowing the callers will expose the contexts in which these attributes are being changed, and therefore, potentially where `verify_rwx()` is protecting something.

{
  "Expression": "__change_page_attr",
  "PathPrefix": "arch/x86/mm/pat/set_memory.c"
}

{
  "Output": "arch/x86/mm/pat/set_memory.c=1805=static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr,\n--\narch/x86/mm/pat/set_memory.c-1849-\narch/x86/mm/pat/set_memory.c:1850:static int __change_page_attr(struct cpa_data *cpa, int primary)\narch/x86/mm/pat/set_memory.c-1851-{\n--\narch/x86/mm/pat/set_memory.c-1927-\narch/x86/mm/pat/set_memory.c:1928:static int __change_page_attr_set_clr(struct cpa_data *cpa, int primary);\narch/x86/mm/pat/set_memory.c-1929-\n--\narch/x86/mm/pat/set_memory.c=1933=static int cpa_process_alias(struct cpa_data *cpa)\n--\narch/x86/mm/pat/set_memory.c-1963-\narch/x86/mm/pat/set_memory.c:1964:\t\tret = __change_page_attr_set_clr(\u0026alias_cpa, 0);\narch/x86/mm/pat/set_memory.c-1965-\t\tif (ret)\n--\narch/x86/mm/pat/set_memory.c-1997-\t\t */\narch/x86/mm/pat/set_memory.c:1998:\t\t__change_page_attr_set_clr(\u0026alias_cpa, 0);\narch/x86/mm/pat/set_memory.c-1999-\t}\n--\narch/x86/mm/pat/set_memory.c-2004-\narch/x86/mm/pat/set_memory.c:2005:static int __change_page_attr_set_clr(struct cpa_data *cpa, int primary)\narch/x86/mm/pat/set_memory.c-2006-{\n--\narch/x86/mm/pat/set_memory.c-2053-\t\t\tguard(spinlock)(\u0026cpa_lock);\narch/x86/mm/pat/set_memory.c:2054:\t\t\tret = __change_page_attr(cpa, primary);\narch/x86/mm/pat/set_memory.c-2055-\t\t} else {\narch/x86/mm/pat/set_memory.c:2056:\t\t\tret = __change_page_attr(cpa, primary);\narch/x86/mm/pat/set_memory.c-2057-\t\t}\n--\narch/x86/mm/pat/set_memory.c=2083=static int change_page_attr_set_clr(unsigned long *addr, int numpages,\n--\narch/x86/mm/pat/set_memory.c-2138-\narch/x86/mm/pat/set_memory.c:2139:\tret = __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2140-\n--\narch/x86/mm/pat/set_memory.c=2409=static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)\n--\narch/x86/mm/pat/set_memory.c-2438-\narch/x86/mm/pat/set_memory.c:2439:\tret = __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2440-\n--\narch/x86/mm/pat/set_memory.c=2636=static int __set_pages_p(struct page *page, int numpages, unsigned int cpa_flags)\n--\narch/x86/mm/pat/set_memory.c-2651-\t */\narch/x86/mm/pat/set_memory.c:2652:\treturn __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2653-}\n--\narch/x86/mm/pat/set_memory.c=2655=static int __set_pages_np(struct page *page, int numpages, unsigned int cpa_flags)\n--\narch/x86/mm/pat/set_memory.c-2670-\t */\narch/x86/mm/pat/set_memory.c:2671:\treturn __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2672-}\n--\narch/x86/mm/pat/set_memory.c=2746=int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,\n--\narch/x86/mm/pat/set_memory.c-2770-\narch/x86/mm/pat/set_memory.c:2771:\tretval = __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2772-\t__flush_tlb_all();\n--\narch/x86/mm/pat/set_memory.c=2783=int __init kernel_unmap_pages_in_pgd(pgd_t *pgd, unsigned long address,\n--\narch/x86/mm/pat/set_memory.c-2805-\narch/x86/mm/pat/set_memory.c:2806:\tretval = __change_page_attr_set_clr(\u0026cpa, 1);\narch/x86/mm/pat/set_memory.c-2807-\t__flush_tlb_all();\n"
}

							input: 39416
							output: 30
							thoughts: 385

**Analyzing the set_memory.c Module**

Okay, let's break this down. My initial focus is on `verify_rwx`, and I see it's a static inline within `arch/x86/mm/pat/set_memory.c`. Given that, I want to map out the relevant symbols within that file and determine which ones are exported (or non-static functions) that call or include `verify_rwx`.

So, from the looks of it the relevant symbols in `arch/x86/mm/pat/set_memory.c` are: `__change_page_attr`, `__change_page_attr_set_clr`, `change_page_attr_set_clr`, `set_memory_ro`, `set_memory_rw`, `set_memory_x`, `set_memory_nx`, `set_memory_rox`, `set_memory_uc`, `set_memory_wc`, `set_memory_wb`, `set_memory_np`, `set_memory_p`, `set_memory_4k`, `set_memory_encrypted`, and `set_memory_decrypted`.

Now, I'll need to figure out which of those are actually exported or non-static functions or functions that include `verify_rwx`. My immediate candidates are: `set_memory_ro`, `set_memory_rw`, `set_memory_x`, `set_memory_nx`, `set_memory_rox`, `set_memory_uc`, `set_memory_wb`, `change_page_attr_set_clr`, and `__change_page_attr`.

Next, I need to check the Kconfig dependencies for `arch/x86/mm/pat/set_memory.c` to see if there's any conditional compilation or other settings that impact its inclusion or behavior. I'll need to look at `arch/x86/mm/Makefile` or `arch/x86/mm/pat/Makefile` to do this. This should give me a more complete picture of the context.

{
  "Expression": "set_memory",
  "PathPrefix": "arch/x86/mm"
}

{
  "Output": "arch/x86/mm/init.c-11-\narch/x86/mm/init.c:12:#include \u003casm/set_memory.h\u003e\narch/x86/mm/init.c-13-#include \u003casm/cpu_device_id.h\u003e\n--\narch/x86/mm/init.c=897=void free_init_pages(const char *what, unsigned long begin, unsigned long end)\n--\narch/x86/mm/init.c-925-\t\tkmemleak_free_part((void *)begin, end - begin);\narch/x86/mm/init.c:926:\t\tset_memory_np(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c-927-\t} else {\n--\narch/x86/mm/init.c-932-\t\t */\narch/x86/mm/init.c:933:\t\tset_memory_nx(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c:934:\t\tset_memory_rw(begin, (end - begin) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init.c-935-\n--\narch/x86/mm/init.c=946=void free_kernel_image_pages(const char *what, void *begin, void *end)\n--\narch/x86/mm/init.c-969-\tif (IS_ENABLED(CONFIG_X86_64) \u0026\u0026 cpu_feature_enabled(X86_FEATURE_PTI))\narch/x86/mm/init.c:970:\t\tset_memory_np_noalias(begin_ul, len_pages);\narch/x86/mm/init.c-971-}\n--\narch/x86/mm/init_32.c-48-#include \u003casm/setup.h\u003e\narch/x86/mm/init_32.c:49:#include \u003casm/set_memory.h\u003e\narch/x86/mm/init_32.c-50-#include \u003casm/page_types.h\u003e\n--\narch/x86/mm/init_32.c=723=static void mark_nxdata_nx(void)\n--\narch/x86/mm/init_32.c-736-\t\tprintk(KERN_INFO \"NX-protecting the kernel data: %luk\\n\", size \u003e\u003e 10);\narch/x86/mm/init_32.c:737:\tset_memory_nx(start, size \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_32.c-738-}\n--\narch/x86/mm/init_64.c-51-#include \u003casm/numa.h\u003e\narch/x86/mm/init_64.c:52:#include \u003casm/set_memory.h\u003e\narch/x86/mm/init_64.c-53-#include \u003casm/init.h\u003e\n--\narch/x86/mm/init_64.c=1359=void mark_rodata_ro(void)\n--\narch/x86/mm/init_64.c-1369-\t       (end - start) \u003e\u003e 10);\narch/x86/mm/init_64.c:1370:\tset_memory_ro(start, (end - start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1371-\n--\narch/x86/mm/init_64.c-1386-\tall_end = roundup((unsigned long)_brk_end, PMD_SIZE);\narch/x86/mm/init_64.c:1387:\tset_memory_nx(text_end, (all_end - text_end) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1388-\n--\narch/x86/mm/init_64.c-1392-\tprintk(KERN_INFO \"Testing CPA: undo %lx-%lx\\n\", start, end);\narch/x86/mm/init_64.c:1393:\tset_memory_rw(start, (end-start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1394-\narch/x86/mm/init_64.c-1395-\tprintk(KERN_INFO \"Testing CPA: again\\n\");\narch/x86/mm/init_64.c:1396:\tset_memory_ro(start, (end-start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/init_64.c-1397-#endif\n--\narch/x86/mm/init_64.c-1415-/* Adjustable memory block size */\narch/x86/mm/init_64.c:1416:static unsigned long set_memory_block_size;\narch/x86/mm/init_64.c:1417:int __init set_memory_block_size_order(unsigned int order)\narch/x86/mm/init_64.c-1418-{\n--\narch/x86/mm/init_64.c-1423-\narch/x86/mm/init_64.c:1424:\tset_memory_block_size = size;\narch/x86/mm/init_64.c-1425-\treturn 0;\n--\narch/x86/mm/init_64.c=1428=static unsigned long probe_memory_block_size(void)\n--\narch/x86/mm/init_64.c-1433-\t/* If memory block size has been set, then use it */\narch/x86/mm/init_64.c:1434:\tbz = set_memory_block_size;\narch/x86/mm/init_64.c-1435-\tif (bz)\n--\narch/x86/mm/ioremap.c-22-\narch/x86/mm/ioremap.c:23:#include \u003casm/set_memory.h\u003e\narch/x86/mm/ioremap.c-24-#include \u003casm/e820/api.h\u003e\n--\narch/x86/mm/ioremap.c=45=int ioremap_change_attr(unsigned long vaddr, unsigned long size,\n--\narch/x86/mm/ioremap.c-53-\tdefault:\narch/x86/mm/ioremap.c:54:\t\terr = _set_memory_uc(vaddr, nrpages);\narch/x86/mm/ioremap.c-55-\t\tbreak;\narch/x86/mm/ioremap.c-56-\tcase _PAGE_CACHE_MODE_WC:\narch/x86/mm/ioremap.c:57:\t\terr = _set_memory_wc(vaddr, nrpages);\narch/x86/mm/ioremap.c-58-\t\tbreak;\narch/x86/mm/ioremap.c-59-\tcase _PAGE_CACHE_MODE_WT:\narch/x86/mm/ioremap.c:60:\t\terr = _set_memory_wt(vaddr, nrpages);\narch/x86/mm/ioremap.c-61-\t\tbreak;\narch/x86/mm/ioremap.c-62-\tcase _PAGE_CACHE_MODE_WB:\narch/x86/mm/ioremap.c:63:\t\terr = _set_memory_wb(vaddr, nrpages);\narch/x86/mm/ioremap.c-64-\t\tbreak;\n--\narch/x86/mm/mem_encrypt_amd.c-26-#include \u003casm/bootparam.h\u003e\narch/x86/mm/mem_encrypt_amd.c:27:#include \u003casm/set_memory.h\u003e\narch/x86/mm/mem_encrypt_amd.c-28-#include \u003casm/cacheflush.h\u003e\n--\narch/x86/mm/mem_encrypt_amd.c=57=static inline void __init snp_memcpy(void *dst, void *src, size_t sz,\n--\narch/x86/mm/mem_encrypt_amd.c-66-\t\t */\narch/x86/mm/mem_encrypt_amd.c:67:\t\tearly_snp_set_memory_shared((unsigned long)__va(paddr), paddr, npages);\narch/x86/mm/mem_encrypt_amd.c-68-\n--\narch/x86/mm/mem_encrypt_amd.c-71-\t\t/* Restore the page state after the memcpy. */\narch/x86/mm/mem_encrypt_amd.c:72:\t\tearly_snp_set_memory_private((unsigned long)__va(paddr), paddr, npages);\narch/x86/mm/mem_encrypt_amd.c-73-\t} else {\n--\narch/x86/mm/mem_encrypt_amd.c=286=static int amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-292-\tif (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) \u0026\u0026 !enc)\narch/x86/mm/mem_encrypt_amd.c:293:\t\tsnp_set_memory_shared(vaddr, npages);\narch/x86/mm/mem_encrypt_amd.c-294-\n--\narch/x86/mm/mem_encrypt_amd.c=299=static int amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-305-\tif (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) \u0026\u0026 enc)\narch/x86/mm/mem_encrypt_amd.c:306:\t\tsnp_set_memory_private(vaddr, npages);\narch/x86/mm/mem_encrypt_amd.c-307-\n--\narch/x86/mm/mem_encrypt_amd.c=358=static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-378-\t\t */\narch/x86/mm/mem_encrypt_amd.c:379:\t\tearly_snp_set_memory_shared((unsigned long)__va(d.pa), d.pa, 1);\narch/x86/mm/mem_encrypt_amd.c-380-\t}\n--\narch/x86/mm/mem_encrypt_amd.c-388-\tif (enc)\narch/x86/mm/mem_encrypt_amd.c:389:\t\tearly_snp_set_memory_private((unsigned long)__va(d.pa), d.pa, 1);\narch/x86/mm/mem_encrypt_amd.c-390-}\narch/x86/mm/mem_encrypt_amd.c-391-\narch/x86/mm/mem_encrypt_amd.c:392:static int __init early_set_memory_enc_dec(unsigned long vaddr,\narch/x86/mm/mem_encrypt_amd.c-393-\t\t\t\t\t   unsigned long size, bool enc)\n--\narch/x86/mm/mem_encrypt_amd.c-461-\narch/x86/mm/mem_encrypt_amd.c:462:int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size)\narch/x86/mm/mem_encrypt_amd.c-463-{\narch/x86/mm/mem_encrypt_amd.c:464:\treturn early_set_memory_enc_dec(vaddr, size, false);\narch/x86/mm/mem_encrypt_amd.c-465-}\narch/x86/mm/mem_encrypt_amd.c-466-\narch/x86/mm/mem_encrypt_amd.c:467:int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)\narch/x86/mm/mem_encrypt_amd.c-468-{\narch/x86/mm/mem_encrypt_amd.c:469:\treturn early_set_memory_enc_dec(vaddr, size, true);\narch/x86/mm/mem_encrypt_amd.c-470-}\n--\narch/x86/mm/mem_encrypt_amd.c=543=void __init mem_encrypt_free_decrypted_mem(void)\n--\narch/x86/mm/mem_encrypt_amd.c-560-\tif (sme_me_mask) {\narch/x86/mm/mem_encrypt_amd.c:561:\t\tr = set_memory_encrypted(vaddr, npages);\narch/x86/mm/mem_encrypt_amd.c-562-\t\tif (r) {\n--\narch/x86/mm/pat/Makefile-2-\narch/x86/mm/pat/Makefile:3:obj-y\t\t\t\t:= set_memory.o memtype.o\narch/x86/mm/pat/Makefile-4-\n--\narch/x86/mm/pat/memtype.c=492=static u64 sanitize_phys(u64 address)\n--\narch/x86/mm/pat/memtype.c-496-\t * for a \"decoy\" virtual address (bit 63 clear) passed to\narch/x86/mm/pat/memtype.c:497:\t * set_memory_X(). __pa() on a \"decoy\" address results in a\narch/x86/mm/pat/memtype.c-498-\t * physical address with bit 63 set.\n--\narch/x86/mm/pat/set_memory.c-22-#include \u003clinux/cc_platform.h\u003e\narch/x86/mm/pat/set_memory.c:23:#include \u003clinux/set_memory.h\u003e\narch/x86/mm/pat/set_memory.c-24-#include \u003clinux/memregion.h\u003e\n--\narch/x86/mm/pat/set_memory.c=274=static bool __cpa_pfn_in_highmap(unsigned long pfn)\n--\narch/x86/mm/pat/set_memory.c-286- * UC to avoid speculative access logging another error. But passing the\narch/x86/mm/pat/set_memory.c:287: * address of the 1:1 mapping to set_memory_uc() is a fine way to encourage a\narch/x86/mm/pat/set_memory.c-288- * speculative access. So we cheat and flip the top bit of the address. This\n--\narch/x86/mm/pat/set_memory.c=2187=static inline int cpa_clear_pages_array(struct page **pages, int numpages,\n--\narch/x86/mm/pat/set_memory.c-2193-\narch/x86/mm/pat/set_memory.c:2194:int _set_memory_uc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2195-{\n--\narch/x86/mm/pat/set_memory.c-2198-\t * If you really need strong UC use ioremap_uc(), but note\narch/x86/mm/pat/set_memory.c:2199:\t * that you cannot override IO areas with set_memory_*() as\narch/x86/mm/pat/set_memory.c-2200-\t * these helpers cannot work with IO memory.\n--\narch/x86/mm/pat/set_memory.c-2206-\narch/x86/mm/pat/set_memory.c:2207:int set_memory_uc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2208-{\n--\narch/x86/mm/pat/set_memory.c-2218-\narch/x86/mm/pat/set_memory.c:2219:\tret = _set_memory_uc(addr, numpages);\narch/x86/mm/pat/set_memory.c-2220-\tif (ret)\n--\narch/x86/mm/pat/set_memory.c-2229-}\narch/x86/mm/pat/set_memory.c:2230:EXPORT_SYMBOL(set_memory_uc);\narch/x86/mm/pat/set_memory.c-2231-\narch/x86/mm/pat/set_memory.c:2232:int _set_memory_wc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2233-{\n--\narch/x86/mm/pat/set_memory.c-2247-\narch/x86/mm/pat/set_memory.c:2248:int set_memory_wc(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2249-{\n--\narch/x86/mm/pat/set_memory.c-2256-\narch/x86/mm/pat/set_memory.c:2257:\tret = _set_memory_wc(addr, numpages);\narch/x86/mm/pat/set_memory.c-2258-\tif (ret)\n--\narch/x86/mm/pat/set_memory.c-2262-}\narch/x86/mm/pat/set_memory.c:2263:EXPORT_SYMBOL(set_memory_wc);\narch/x86/mm/pat/set_memory.c-2264-\narch/x86/mm/pat/set_memory.c:2265:int _set_memory_wt(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2266-{\n--\narch/x86/mm/pat/set_memory.c-2270-\narch/x86/mm/pat/set_memory.c:2271:int _set_memory_wb(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2272-{\n--\narch/x86/mm/pat/set_memory.c-2277-\narch/x86/mm/pat/set_memory.c:2278:int set_memory_wb(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2279-{\n--\narch/x86/mm/pat/set_memory.c-2281-\narch/x86/mm/pat/set_memory.c:2282:\tret = _set_memory_wb(addr, numpages);\narch/x86/mm/pat/set_memory.c-2283-\tif (ret)\n--\narch/x86/mm/pat/set_memory.c-2288-}\narch/x86/mm/pat/set_memory.c:2289:EXPORT_SYMBOL(set_memory_wb);\narch/x86/mm/pat/set_memory.c-2290-\n--\narch/x86/mm/pat/set_memory.c=2293=int set_mce_nospec(unsigned long pfn)\n--\narch/x86/mm/pat/set_memory.c-2302-\t * We would like to just call:\narch/x86/mm/pat/set_memory.c:2303:\t *      set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1);\narch/x86/mm/pat/set_memory.c-2304-\t * but doing that would radically increase the odds of a\n--\narch/x86/mm/pat/set_memory.c-2309-\t * that looks just like the one we want, but has bit 63 flipped.\narch/x86/mm/pat/set_memory.c:2310:\t * This relies on set_memory_XX() properly sanitizing any __pa()\narch/x86/mm/pat/set_memory.c-2311-\t * results with __PHYSICAL_MASK or PTE_PFN_MASK.\n--\narch/x86/mm/pat/set_memory.c-2314-\narch/x86/mm/pat/set_memory.c:2315:\trc = set_memory_np(decoy_addr, 1);\narch/x86/mm/pat/set_memory.c-2316-\tif (rc)\n--\narch/x86/mm/pat/set_memory.c=2323=int clear_mce_nospec(unsigned long pfn)\n--\narch/x86/mm/pat/set_memory.c-2326-\narch/x86/mm/pat/set_memory.c:2327:\treturn set_memory_p(addr, 1);\narch/x86/mm/pat/set_memory.c-2328-}\narch/x86/mm/pat/set_memory.c=2329=EXPORT_SYMBOL_GPL(clear_mce_nospec);\n--\narch/x86/mm/pat/set_memory.c-2331-\narch/x86/mm/pat/set_memory.c:2332:int set_memory_x(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2333-{\n--\narch/x86/mm/pat/set_memory.c-2339-\narch/x86/mm/pat/set_memory.c:2340:int set_memory_nx(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2341-{\n--\narch/x86/mm/pat/set_memory.c-2347-\narch/x86/mm/pat/set_memory.c:2348:int set_memory_ro(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2349-{\n--\narch/x86/mm/pat/set_memory.c-2352-\narch/x86/mm/pat/set_memory.c:2353:int set_memory_rox(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2354-{\n--\narch/x86/mm/pat/set_memory.c-2363-\narch/x86/mm/pat/set_memory.c:2364:int set_memory_rw(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2365-{\n--\narch/x86/mm/pat/set_memory.c-2368-\narch/x86/mm/pat/set_memory.c:2369:int set_memory_np(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2370-{\n--\narch/x86/mm/pat/set_memory.c-2373-\narch/x86/mm/pat/set_memory.c:2374:int set_memory_np_noalias(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2375-{\n--\narch/x86/mm/pat/set_memory.c-2380-\narch/x86/mm/pat/set_memory.c:2381:int set_memory_p(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2382-{\n--\narch/x86/mm/pat/set_memory.c-2385-\narch/x86/mm/pat/set_memory.c:2386:int set_memory_4k(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2387-{\n--\narch/x86/mm/pat/set_memory.c-2392-\narch/x86/mm/pat/set_memory.c:2393:int set_memory_nonglobal(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2394-{\n--\narch/x86/mm/pat/set_memory.c-2398-\narch/x86/mm/pat/set_memory.c:2399:int set_memory_global(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2400-{\n--\narch/x86/mm/pat/set_memory.c-2405-/*\narch/x86/mm/pat/set_memory.c:2406: * __set_memory_enc_pgtable() is used for the hypervisors that get\narch/x86/mm/pat/set_memory.c-2407- * informed about \"encryption\" status via page tables.\narch/x86/mm/pat/set_memory.c-2408- */\narch/x86/mm/pat/set_memory.c:2409:static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)\narch/x86/mm/pat/set_memory.c-2410-{\n--\narch/x86/mm/pat/set_memory.c=2473=static DECLARE_RWSEM(mem_enc_lock);\n--\narch/x86/mm/pat/set_memory.c-2480- */\narch/x86/mm/pat/set_memory.c:2481:bool set_memory_enc_stop_conversion(void)\narch/x86/mm/pat/set_memory.c-2482-{\n--\narch/x86/mm/pat/set_memory.c-2494-\narch/x86/mm/pat/set_memory.c:2495:static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)\narch/x86/mm/pat/set_memory.c-2496-{\n--\narch/x86/mm/pat/set_memory.c-2502-\narch/x86/mm/pat/set_memory.c:2503:\t\tret = __set_memory_enc_pgtable(addr, numpages, enc);\narch/x86/mm/pat/set_memory.c-2504-\n--\narch/x86/mm/pat/set_memory.c-2510-\narch/x86/mm/pat/set_memory.c:2511:int set_memory_encrypted(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2512-{\narch/x86/mm/pat/set_memory.c:2513:\treturn __set_memory_enc_dec(addr, numpages, true);\narch/x86/mm/pat/set_memory.c-2514-}\narch/x86/mm/pat/set_memory.c:2515:EXPORT_SYMBOL_GPL(set_memory_encrypted);\narch/x86/mm/pat/set_memory.c-2516-\narch/x86/mm/pat/set_memory.c:2517:int set_memory_decrypted(unsigned long addr, int numpages)\narch/x86/mm/pat/set_memory.c-2518-{\narch/x86/mm/pat/set_memory.c:2519:\treturn __set_memory_enc_dec(addr, numpages, false);\narch/x86/mm/pat/set_memory.c-2520-}\narch/x86/mm/pat/set_memory.c:2521:EXPORT_SYMBOL_GPL(set_memory_decrypted);\narch/x86/mm/pat/set_memory.c-2522-\narch/x86/mm/pat/set_memory.c=2523=int set_pages_uc(struct page *page, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2526-\narch/x86/mm/pat/set_memory.c:2527:\treturn set_memory_uc(addr, numpages);\narch/x86/mm/pat/set_memory.c-2528-}\n--\narch/x86/mm/pat/set_memory.c=2589=int set_pages_wb(struct page *page, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2592-\narch/x86/mm/pat/set_memory.c:2593:\treturn set_memory_wb(addr, numpages);\narch/x86/mm/pat/set_memory.c-2594-}\n--\narch/x86/mm/pat/set_memory.c=2622=int set_pages_ro(struct page *page, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2625-\narch/x86/mm/pat/set_memory.c:2626:\treturn set_memory_ro(addr, numpages);\narch/x86/mm/pat/set_memory.c-2627-}\n--\narch/x86/mm/pat/set_memory.c=2629=int set_pages_rw(struct page *page, int numpages)\n--\narch/x86/mm/pat/set_memory.c-2632-\narch/x86/mm/pat/set_memory.c:2633:\treturn set_memory_rw(addr, numpages);\narch/x86/mm/pat/set_memory.c-2634-}\n--\narch/x86/mm/pti.c-40-#include \u003casm/sections.h\u003e\narch/x86/mm/pti.c:41:#include \u003casm/set_memory.h\u003e\narch/x86/mm/pti.c-42-#include \u003casm/bugs.h\u003e\n--\narch/x86/mm/pti.c=571=static void pti_clone_kernel_text(void)\n--\narch/x86/mm/pti.c-600-\t/* Set the global bit for normal non-__init kernel text: */\narch/x86/mm/pti.c:601:\tset_memory_global(start, (end_global - start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/pti.c-602-}\n--\narch/x86/mm/pti.c=604=static void pti_set_kernel_image_nonglobal(void)\n--\narch/x86/mm/pti.c-619-\t */\narch/x86/mm/pti.c:620:\tset_memory_nonglobal(start, (end - start) \u003e\u003e PAGE_SHIFT);\narch/x86/mm/pti.c-621-}\n"
}

							input: 48405
							output: 32
							thoughts: 89

**My Assessment of the x86 Memory Protection Code**

Okay, so `arch/x86/mm/pat/set_memory.c` is *always* compiled into the x86 kernel; that's good to know – it's fundamental. The `Makefile` confirms this (`obj-y := set_memory.o memtype.o`). Now, my immediate thought is to check if its behaviour is tied to some configuration options. I need to see if `STRICT_KERNEL_RWX` or something related to Control-Flow Attenuation (CPA), like the `CPA` macro, has any influence on its operation. A quick inspection of `arch/x86/Kconfig` should reveal any relevant configuration dependencies and whether I need to consider those in my analysis.

{
  "Expression": "STRICT_KERNEL_RWX",
  "PathPrefix": "arch/x86"
}

{
  "Output": "arch/x86/Kconfig=58=config X86\n--\narch/x86/Kconfig-107-\tselect ARCH_HAS_SET_DIRECT_MAP\narch/x86/Kconfig:108:\tselect ARCH_HAS_STRICT_KERNEL_RWX\narch/x86/Kconfig-109-\tselect ARCH_HAS_STRICT_MODULE_RWX\n--\narch/x86/kernel/alternative.c=172=static void its_fini_core(void)\narch/x86/kernel/alternative.c-173-{\narch/x86/kernel/alternative.c:174:\tif (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))\narch/x86/kernel/alternative.c-175-\t\tits_pages_protect(\u0026its_pages);\n--\narch/x86/mm/pat/set_memory.c=671=static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,\n--\narch/x86/mm/pat/set_memory.c-703-\t * false positive.\narch/x86/mm/pat/set_memory.c:704:\t * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,\narch/x86/mm/pat/set_memory.c-705-\t * the warning can be removed completely.\n"
}

							input: 49064
							output: 21
							thoughts: 27

Okay, here's my take on those thoughts, framed as an expert's inner monologue:

**Investigating `STRICT_KERNEL_RWX` Configuration**

Alright, before I dive into the deep end, let's just quickly confirm where `STRICT_KERNEL_RWX` is defined within the kernel's configuration system. I suspect it's either in the general initialization config, `init/Kconfig`, or perhaps a more architecture-specific file, like `arch/Kconfig`. It's critical to know *exactly* where this config option is defined to understand its scope and how it's handled during build and configuration time. I need to pinpoint the exact location to properly assess its impact and how I can, if necessary, customize or override this default behavior. Time to crack open those Kconfig files!

{
  "Expression": "config STRICT_KERNEL_RWX"
}

{
  "Output": "arch/Kconfig=1595=config ARCH_HAS_STRICT_KERNEL_RWX\n--\narch/Kconfig-1597-\narch/Kconfig:1598:config STRICT_KERNEL_RWX\narch/Kconfig-1599-\tbool \"Make kernel text and rodata read-only\" if ARCH_OPTIONAL_KERNEL_RWX\n"
}

							input: 49386
							output: 33
							thoughts: 18

Here's my take on the thought process:

**Diving into the Kernel Configuration**

Okay, time to get down to brass tacks. I need to investigate something related to kernel configuration, and my gut feeling tells me it's likely housed in `arch/Kconfig`. I'm reasonably sure of that directory, it's where the architectural-specific configurations usually live. I'll focus my search around line 1598. No need to get distracted by a wider search when I have a good idea where to start digging. Let's see what's brewing in that particular area of the config file. Time to open that file and get to it.

{
  "File": "arch/Kconfig",
  "FirstLine": 1595,
  "LineCount": 20
}

{
  "Contents": "1595:\tconfig ARCH_HAS_STRICT_KERNEL_RWX\n1596:\t\tdef_bool n\n1597:\t\n1598:\tconfig STRICT_KERNEL_RWX\n1599:\t\tbool \"Make kernel text and rodata read-only\" if ARCH_OPTIONAL_KERNEL_RWX\n1600:\t\tdepends on ARCH_HAS_STRICT_KERNEL_RWX\n1601:\t\tdefault !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT\n1602:\t\thelp\n1603:\t\t  If this is set, kernel text and rodata memory will be made read-only,\n1604:\t\t  and non-text memory will be made non-executable. This provides\n1605:\t\t  protection against certain security exploits (e.g. executing the heap\n1606:\t\t  or modifying text)\n1607:\t\n1608:\t\t  These features are considered standard security practice these days.\n1609:\t\t  You should say Y here in almost all cases.\n1610:\t\n1611:\tconfig ARCH_HAS_STRICT_MODULE_RWX\n1612:\t\tdef_bool n\n1613:\t\n1614:\tconfig STRICT_MODULE_RWX\n"
}

							input: 49912
							output: 210
							thoughts: 1060

**Analysis of W^X Verification Logic in x86 Memory Management**

Okay, let's break this down. First, I confirmed that `STRICT_KERNEL_RWX` defaults to `y`, so we're good there. The configuration context is crucial: we're dealing with `EnableConfigs`: `["STRICT_KERNEL_RWX"]`.

Now, let's hone in on the core of the matter. The `FocusSymbols` are carefully selected to avoid the noise of ubiquitous functions like `vfree` or `kmalloc`. Instead, I'm concentrating on the specific entry points and related functions within `arch/x86/mm/pat/set_memory.c`. Specifically, I'm focusing on the `change_page_attr_set_clr`, `__change_page_attr_set_clr`, `__change_page_attr`, `__should_split_large_page`, `set_memory_ro`, `set_memory_rw`, `set_memory_rox`, `set_memory_x`, and `set_memory_nx`. These are all relevant functions in the `arch/x86/mm/pat/set_memory.c` file.

The git diff confirms the changes. We're modifying the W^X verification logic, specifically in the `verify_rwx` function. The patch introduces a conditional warning related to `kernel_set_to_readonly` and rodata protection. This is significant because it provides a mechanism to handle potential false positives, particularly before the `debug_checkwx()` becomes mandatory.

The subsystem is clearly x86 memory management, specifically dealing with Change Page Attributes (CPA). The reachability is well-defined: this code path is fully reachable on x86_64 whenever page protection attributes are modified, which happens frequently (modules, BPF JIT, kprobes/ftrace, direct map manipulation). This makes it highly relevant for fuzzing.

Therefore, `WorthFuzzing` should be set to `true`, and the `EnableConfigs` and `FocusSymbols` are appropriate. The patch modifies W^X verification, and this makes it a suitable area for investigation.

{
  "EnableConfigs": [
    "STRICT_KERNEL_RWX"
  ],
  "FocusSymbols": [
    "__change_page_attr",
    "__should_split_large_page",
    "change_page_attr_set_clr",
    "set_memory_ro",
    "set_memory_rw",
    "set_memory_rox",
    "set_memory_nx",
    "set_memory_x"
  ],
  "Reasoning": "The patch modifies the W^X permission verification logic (verify_rwx) within x86 Change Page Attributes (CPA) in arch/x86/mm/pat/set_memory.c. This is reachable core memory management code executed whenever kernel page protections are adjusted (such as via BPF JIT, ftrace, module loading/unloading, or driver memory attribute changes). It introduces new conditional warning behavior when kernel_set_to_readonly is false.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "STRICT_KERNEL_RWX"
  ],
  "FocusSymbols": [
    "__change_page_attr",
    "__should_split_large_page",
    "change_page_attr_set_clr",
    "set_memory_ro",
    "set_memory_rw",
    "set_memory_rox",
    "set_memory_nx",
    "set_memory_x"
  ],
  "Reasoning": "The patch modifies the W^X permission verification logic (verify_rwx) within x86 Change Page Attributes (CPA) in arch/x86/mm/pat/set_memory.c. This is reachable core memory management code executed whenever kernel page protections are adjusted (such as via BPF JIT, ftrace, module loading/unloading, or driver memory attribute changes). It introduces new conditional warning behavior when kernel_set_to_readonly is false.",
  "WorthFuzzing": true
}

{
  "WorthFuzzing": true
}

{
  "KMSANReasoning": "The patch modifies `verify_rwx()` in `arch/x86/mm/pat/set_memory.c` to log a warning via `pr_warn_once` instead of triggering a full `WARN_ONCE` when a W^X violation is detected before kernel text has been marked read-only (`kernel_set_to_readonly` is false). \n\nThis change only touches logging and control flow based on an existing global boolean flag and scalar page-table protection values. It does not introduce any memory allocations, does not touch uninitialized heap/stack memory or structure padding, and does not expose any kernel data to user space. Therefore, there are no uninitialized memory risks, and KMSAN fuzzing is not required.",
  "NeedsKMSAN": false
}

You are an expert Linux kernel security engineer specializing in kernel memory
error detectors (KASAN and KMSAN). Your job is to review the provided patch series and
determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer)
fuzzing session in addition to standard KASAN fuzzing.

CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN:
- Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable
  a comprehensive suite of debugging tools and sanitizers, including KASAN
  (out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP
  (locking bugs and deadlocks), UB-sanitizers, and memory corruption checks.
- KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap,
  or page allocations) and kernel-to-user memory info-leaks.

Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN,
LOCKDEP, OR OTHER STANDARD BUG DETECTORS.
A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY
set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks
that are detected ONLY by KMSAN.

Look holistically at the patch series and surrounding code. Even if no direct
uninitialized field accesses or new buffer allocations are added in the diff itself,
a patch may alter control flow, bounds checking, or data length calculations in ways
that change how the rest of the code operates on existing buffers (e.g. allowing
uninitialized stack/heap memory to be read, copied to user space, or used in control
flow). Do not hesitate to use your code access tools to inspect the surrounding code,
called functions, and callers.

Set NeedsKMSAN=true ONLY IF the patch introduces or modifies:
1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb
   attributes, ioctl output arguments, socket options, or BPF buffers) where fields
   or structure padding might not be fully initialized/zeroed.
2. Conditional logic or branching that depends on potentially uninitialized variables
   or struct fields.
3. Allocation or initialization of complex data structures where uninitialized fields
   could be read later in reachable code paths.
4. Bounds checks, lengths, or logic in a way that allows surrounding code to access
   uninitialized bytes of existing buffers.

Set NeedsKMSAN=false IF:
- The code changes primarily risk out-of-bounds access, array overflows, NULL pointer
  dereferences, locking deadlocks, or use-after-free bugs (these are already caught
  by KASAN, LOCKDEP, or standard bug detectors).
- All stack/heap structures touched or introduced by the patch are fully zeroed
  or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied.
- The patch does not introduce any risk of uninitialized memory usage or info-leaks.

Use your code access tools to inspect the surrounding code if necessary, then provide
detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch.
Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

Target architecture: amd64

For your convenience, here is the diff of the changes:
commit bdd6d4eedaaf432f7fba37c2efc88b8459af8020
Author: syz-cluster <triage@syzkaller.com>
Date:   Fri Sep 11 12:37:43 2026 +0000

    syz-cluster: applied patch under review

diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index b3060000da8d1..a4f7fe69e6922 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -697,6 +697,21 @@ static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long star
 		return new;
 
 	end = start + npg * PAGE_SIZE - 1;
+
+	/*
+	 * If the kernel text is still RWX, gently complain, this could be a
+	 * false positive.
+	 * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,
+	 * the warning can be removed completely.
+	 */
+	if (!kernel_set_to_readonly) {
+		pr_warn_once(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n",
+		  (unsigned long long)pgprot_val(old),
+		  (unsigned long long)pgprot_val(new),
+		  start, end, pfn);
+		return new;
+	}
+
 	WARN_ONCE(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n",
 		  (unsigned long long)pgprot_val(old),
 		  (unsigned long long)pgprot_val(new),

							input: 2336
							output: 43
							thoughts: 647

**Evaluating the Need for KMSAN Fuzzing in `arch/x86/mm/pat/set_memory.c`**

Okay, here's the deal. I'm being asked to figure out whether a patch in `arch/x86/mm/pat/set_memory.c` warrants KMSAN fuzzing, or if KASAN and the standard detectors are good enough. Let's break this down systematically.

First, the risk analysis. This is a pretty straightforward request: it's a defensive security engineering question within Linux kernel QA triage. The severity isn't critical; we're just making sure our bases are covered. So, my action is to provide a complete evaluation.

Now, let's dive into the patch itself. Looking at the diff, it appears to be adding a warning related to W^X violations. Specifically, it seems like the patch checks if code is being made writable after being read-only in the kernel text. There's a conditional check here: If the kernel isn't configured for strict read-only text, a warning is printed. Otherwise, `WARN_ONCE` is used. This is clearly related to protecting against code injection vulnerabilities.

I'll need to go deeper than just glancing at the diff. I'll use either `read-file` or `grepper` to get the broader context within `arch/x86/mm/pat/set_memory.c`, to understand exactly what this `set_memory.c` code is doing and the potential impact of this change. From there, I can determine if uninitialized memory is a concern in the patched code. Once I get the wider picture, I'll be in a better position to determine if KMSAN fuzzing is necessary, or if standard detectors are adequate.

{
  "File": "arch/x86/mm/pat/set_memory.c",
  "FirstLine": 690,
  "LineCount": 40
}

{
  "Contents": " 690:\t\t\treturn new;\n 691:\t\n 692:\t\tif ((pgprot_val(new) \u0026 (_PAGE_RW | _PAGE_NX)) != _PAGE_RW)\n 693:\t\t\treturn new;\n 694:\t\n 695:\t\t/* Non-leaf translation entries can disable writing or execution. */\n 696:\t\tif (!rw || nx)\n 697:\t\t\treturn new;\n 698:\t\n 699:\t\tend = start + npg * PAGE_SIZE - 1;\n 700:\t\n 701:\t\t/*\n 702:\t\t * If the kernel text is still RWX, gently complain, this could be a\n 703:\t\t * false positive.\n 704:\t\t * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX,\n 705:\t\t * the warning can be removed completely.\n 706:\t\t */\n 707:\t\tif (!kernel_set_to_readonly) {\n 708:\t\t\tpr_warn_once(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 709:\t\t\t  (unsigned long long)pgprot_val(old),\n 710:\t\t\t  (unsigned long long)pgprot_val(new),\n 711:\t\t\t  start, end, pfn);\n 712:\t\t\treturn new;\n 713:\t\t}\n 714:\t\n 715:\t\tWARN_ONCE(1, \"CPA detected W^X violation: %016llx -\u003e %016llx range: 0x%016lx - 0x%016lx PFN %lx\\n\",\n 716:\t\t\t  (unsigned long long)pgprot_val(old),\n 717:\t\t\t  (unsigned long long)pgprot_val(new),\n 718:\t\t\t  start, end, pfn);\n 719:\t\n 720:\t\t/*\n 721:\t\t * For now, allow all permission change attempts by returning the\n 722:\t\t * attempted permissions.  This can 'return old' to actively\n 723:\t\t * refuse the permission change at a later time.\n 724:\t\t */\n 725:\t\treturn new;\n 726:\t}\n 727:\t\n 728:\t/*\n 729:\t * Lookup the page table entry for a virtual address in a specific pgd.\n"
}

							input: 4072
							output: 181
							thoughts: 502

**KMSAN Analysis of the Patch**

Okay, let's break this down. That `pr_warn_once` usage immediately caught my eye – the first argument looks suspicious. Is it a typo or a macro? In any case, it's not the standard pattern, so I'm filing that away for now. My immediate focus, however, is on whether this patch introduces any new risks regarding uninitialized memory, copies to userspace, or anything KMSAN would flag.

The patch modifies `verify_rwx()` in `arch/x86/mm/pat/set_memory.c`. Right, so I ran through my mental checklist:

*   **Allocation?** Nope, no stack or heap allocation that could be uninitialized.
*   **User space copy?** Not at all.
*   **Uninitialized memory reads?** No, the arguments to `verify_rwx()` – `old`, `new`, `start`, `end`, `pfn`, `kernel_set_to_readonly` – are all scalar values, booleans, or `pgprot_t` passed by value. This is a clean bill of health.
*   **Buffer manipulation or bounds checks?** Nothing here.
*   **Kernel-to-user memory info-leaks?** No.

Given all of that, it's a straightforward "NeedsKMSAN = false."

Now, let's solidify the reasoning for the record. The patch is changing a `WARN_ONCE` to a `pr_warn_once` in `verify_rwx()`. The change only downgrades the warning if `kernel_set_to_readonly` is false during early boot, when the kernel text permissions are still RWX. It's essentially just a conditional logging change. The code is only working with scalar variables – no uninitialized structures, no writes or copies to userspace, no changes to buffer lengths or calculations. All the information for KMSAN to analyze is scalar and passed by value. Therefore, this patch absolutely does not introduce any KMSAN-relevant issues regarding uninitialized memory or info-leaks. Time to call `set-results`.

{
  "KMSANReasoning": "The patch modifies `verify_rwx()` in `arch/x86/mm/pat/set_memory.c` to log a warning via `pr_warn_once` instead of triggering a full `WARN_ONCE` when a W^X violation is detected before kernel text has been marked read-only (`kernel_set_to_readonly` is false). \n\nThis change only touches logging and control flow based on an existing global boolean flag and scalar page-table protection values. It does not introduce any memory allocations, does not touch uninitialized heap/stack memory or structure padding, and does not expose any kernel data to user space. Therefore, there are no uninitialized memory risks, and KMSAN fuzzing is not required.",
  "NeedsKMSAN": false
}

{
  "KMSANReasoning": "The patch modifies `verify_rwx()` in `arch/x86/mm/pat/set_memory.c` to log a warning via `pr_warn_once` instead of triggering a full `WARN_ONCE` when a W^X violation is detected before kernel text has been marked read-only (`kernel_set_to_readonly` is false). \n\nThis change only touches logging and control flow based on an existing global boolean flag and scalar page-table protection values. It does not introduce any memory allocations, does not touch uninitialized heap/stack memory or structure padding, and does not expose any kernel data to user space. Therefore, there are no uninitialized memory risks, and KMSAN fuzzing is not required.",
  "NeedsKMSAN": false
}

LLM Calls Summary:
Total Calls	Total Tokens	Avg Tokens	Total Duration (Seconds)	Avg Duration (Seconds)

Tool Calls Summary:
Total Calls	Total Duration (Seconds)	Avg Duration (Seconds)