| Seq | Timestamp | Type | Name | Duration |
|---|---|---|---|---|
| 0/0 | 2026/08/27 23:24 | flow | patch-triage |
2mArgs:null Results: {
"EnableConfigs": null,
"FocusSymbols": [
"fixup_exception",
"do_sea"
],
"KMSANReasoning": "The patch modifies `do_sea()` in `arch/arm64/mm/fault.c` to attempt exception fixup via `fixup_exception()` when a Synchronous External Abort (SEA) occurs in kernel mode (`!user_mode(regs)`), allowing graceful recovery (e.g., returning -EFAULT for uaccess faults) instead of dying.\n\nThis change is purely low-level architecture fault/exception handling. It does not introduce any new memory allocations, does not modify data structure fields or padding, does not alter buffer bounds or initialization logic, and does not copy uninitialized kernel memory to userspace. Consequently, there are no uninitialized memory usage or info-leak risks that would require KMSAN fuzzing.",
"NeedsKMSAN": false,
"Reasoning": "The patch allows kernel-mode synchronous external aborts (SEA) to be recovered using exception fixup tables instead of immediately panicking. This modifies core ARM64 fault handling logic reachable during kernel memory accesses that fault with SEA.",
"WorthFuzzing": true
} |
| 1/1 | 2026/08/27 23:24 | action | read-patch-diff |
0mArgs:null Results: {
"PatchDiff": "commit fda78ef7dc0f847f7efa4a952132a2986e23e431\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Thu Aug 27 23:24:04 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c\nindex 0b52557652be6..ca396b4bdda03 100644\n--- a/arch/arm64/mm/fault.c\n+++ b/arch/arm64/mm/fault.c\n@@ -878,6 +878,9 @@ static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)\n \t\treturn 0;\n \t}\n \n+\tif (!user_mode(regs) \u0026\u0026 fixup_exception(regs, esr))\n+\t\treturn 0;\n+\n \tif (esr \u0026 ESR_ELx_FnV) {\n \t\tsiaddr = 0;\n \t} else {\n"
} |
| 2/1 | 2026/08/27 23:24 | agent | patch-evaluator |
1mModel:core Args: null Results: {
"EnableConfigs": null,
"FocusSymbols": [
"fixup_exception",
"do_sea"
],
"Reasoning": "The patch allows kernel-mode synchronous external aborts (SEA) to be recovered using exception fixup tables instead of immediately panicking. This modifies core ARM64 fault handling logic reachable during kernel memory accesses that fault with SEA.",
"WorthFuzzing": true
}Instruction: You are an expert Linux kernel maintainer. Your job is to review a provided patch series and determine if it makes functional changes to the kernel that should be fuzzed. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively use your code access tools to examine the actual source code and confirm any assumptions. Return WorthFuzzing=false if the patch only contains: - Modifications to Documentation/, Kconfig files, or code comments. - Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints. - Changes to numeric constants or macros that do not functionally alter execution flow. - Code paths that are impossible to reach in virtualized environments like GCE or QEMU, even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim). - Code in vendor-specific PCIe switch, SmartNIC, or GPU drivers (e.g., mlxsw, pds_core, qed, ionic, amdgpu) that require physical PCIe hardware cards not emulated in standard QEMU. - Driver .remove, .shutdown, or pci_unregister_driver teardown callbacks (e.g., igb_remove) that are executed only during PCI hot-unplug or sysfs driver unbind operations. If it modifies reachable core kernel logic, drivers, or architectures, use your code search tools to verify the code can be executed, then return WorthFuzzing=true. When returning WorthFuzzing=true, you MUST ALSO: 1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols. Avoid listing generic hot-path functions to prevent skewed test distributions. Prefer non-static, non-inlined API entrypoint functions over internal static helper functions (which are inlined by the compiler and do not have distinct symbol addresses). 2. Identify any specific CONFIG_ options required to properly test this new/modified feature. Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions. Also check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed for Kbuild to compile the code statically into vmlinux. List them in the EnableConfigs output array, and DO NOT add a '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: For your convenience, here is the diff of the changes:
commit fda78ef7dc0f847f7efa4a952132a2986e23e431
Author: syz-cluster <triage@syzkaller.com>
Date: Thu Aug 27 23:24:04 2026 +0000
syz-cluster: applied patch under review
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 0b52557652be6..ca396b4bdda03 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -878,6 +878,9 @@ static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)
return 0;
}
+ if (!user_mode(regs) && fixup_exception(regs, esr))
+ return 0;
+
if (esr & ESR_ELx_FnV) {
siaddr = 0;
} else {
|
| 3/2 | 2026/08/27 23:24 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 2074 output: 39 thoughts: 268 Thoughts: **Analyzing the Fault Handling Code** Okay, let's dive into this. The diff shows a change in `arch/arm64/mm/fault.c`. Specifically, there's a new `if` statement introduced in the `do_sea` function. I recognize that function as related to System Error Abort (SEA) handling on ARM64, dealing with asynchronous aborts. The added condition checks if the exception is *not* in user mode, and then calls `fixup_exception` with the register state and ESR. If `fixup_exception` returns a non-zero value, then the code returns. My initial thought is to figure out what `fixup_exception` does. It seems like the new code is attempting to handle kernel exceptions. I should be able to deduce the general idea, but since this deals with kernel-level memory management and error handling, I need a good understanding of the context. I'll load the `arch/arm64/mm/fault.c` file from the source and browse the surrounding code, especially looking at the definitions of `user_mode` and `fixup_exception`, and also at the surrounding code to determine how this interacts with the rest of the fault handling logic. This addition definitely suggests a need to potentially handle or correct specific kernel exceptions before resorting to a more drastic error handling procedure. I need to understand what specific errors it's trying to mitigate, and why it wasn't there before. |
| 4/2 | 2026/08/27 23:24 | tool | read-file |
0mArgs:{
"File": "arch/arm64/mm/fault.c",
"FirstLine": 850,
"LineCount": 50
}Results: {
"Contents": " 850:\t\n 851:\tstatic int do_alignment_fault(unsigned long far, unsigned long esr,\n 852:\t\t\t\t struct pt_regs *regs)\n 853:\t{\n 854:\t\tif (IS_ENABLED(CONFIG_COMPAT_ALIGNMENT_FIXUPS) \u0026\u0026\n 855:\t\t compat_user_mode(regs))\n 856:\t\t\treturn do_compat_alignment_fixup(far, regs);\n 857:\t\tdo_bad_area(far, esr, regs);\n 858:\t\treturn 0;\n 859:\t}\n 860:\t\n 861:\tstatic int do_bad(unsigned long far, unsigned long esr, struct pt_regs *regs)\n 862:\t{\n 863:\t\treturn 1; /* \"fault\" */\n 864:\t}\n 865:\t\n 866:\tstatic int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)\n 867:\t{\n 868:\t\tconst struct fault_info *inf;\n 869:\t\tunsigned long siaddr;\n 870:\t\n 871:\t\tinf = esr_to_fault_info(esr);\n 872:\t\n 873:\t\tif (user_mode(regs) \u0026\u0026 apei_claim_sea(regs) == 0) {\n 874:\t\t\t/*\n 875:\t\t\t * APEI claimed this as a firmware-first notification.\n 876:\t\t\t * Some processing deferred to task_work before ret_to_user().\n 877:\t\t\t */\n 878:\t\t\treturn 0;\n 879:\t\t}\n 880:\t\n 881:\t\tif (!user_mode(regs) \u0026\u0026 fixup_exception(regs, esr))\n 882:\t\t\treturn 0;\n 883:\t\n 884:\t\tif (esr \u0026 ESR_ELx_FnV) {\n 885:\t\t\tsiaddr = 0;\n 886:\t\t} else {\n 887:\t\t\t/*\n 888:\t\t\t * The architecture specifies that the tag bits of FAR_EL1 are\n 889:\t\t\t * UNKNOWN for synchronous external aborts. Mask them out now\n 890:\t\t\t * so that userspace doesn't see them.\n 891:\t\t\t */\n 892:\t\t\tsiaddr = untagged_addr(far);\n 893:\t\t}\n 894:\t\tadd_taint(TAINT_MACHINE_CHECK, LOCKDEP_STILL_OK);\n 895:\t\tarm64_notify_die(inf-\u003ename, regs, inf-\u003esig, inf-\u003ecode, siaddr, esr);\n 896:\t\n 897:\t\treturn 0;\n 898:\t}\n 899:\t\n"
} |
| 5/2 | 2026/08/27 23:24 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 3432 output: 28 thoughts: 46 Thoughts: Okay, here's my take on those thoughts, framed as my own mental process, given my expertise: **Diving into the Code Change** Alright, time to get my hands dirty. I'm looking at this change and the first thing I need to understand is the context. I see `fixup_exception` and `do_sea` mentioned. My immediate instinct is to figure out their role. Are we fixing an exception handling issue? Is this related to some Sea object interactions? What's the *why* behind this alteration? My brain's already firing up the search tools. I need to pinpoint where these functions are defined, how they're used, and what's changed in their behavior. A quick `grep` for both function names across the codebase is the logical first step. That should provide the immediate context. Hopefully, the surrounding code will tell the story. Let's see what the grep results uncover... |
| 6/2 | 2026/08/27 23:24 | tool | grepper |
0mArgs:{
"Expression": "do_sea",
"PathPrefix": "arch/arm64"
}Results: {
"Output": "arch/arm64/kernel/acpi.c=295=void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size)\n--\narch/arm64/kernel/acpi.c-385- *\narch/arm64/kernel/acpi.c:386: * Used by KVM and the arch do_sea handler.\narch/arm64/kernel/acpi.c-387- * @regs may be NULL when called from process context.\n--\narch/arm64/mm/fault.c=861=static int do_bad(unsigned long far, unsigned long esr, struct pt_regs *regs)\n--\narch/arm64/mm/fault.c-865-\narch/arm64/mm/fault.c:866:static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)\narch/arm64/mm/fault.c-867-{\n--\narch/arm64/mm/fault.c=916=static const struct fault_info fault_info[] = {\n--\narch/arm64/mm/fault.c-932-\t{ do_page_fault,\tSIGSEGV, SEGV_ACCERR,\t\"level 3 permission fault\"\t},\narch/arm64/mm/fault.c:933:\t{ do_sea,\t\tSIGBUS, BUS_OBJERR,\t\"synchronous external abort\"\t},\narch/arm64/mm/fault.c-934-\t{ do_tag_check_fault,\tSIGSEGV, SEGV_MTESERR,\t\"synchronous tag check fault\"\t},\narch/arm64/mm/fault.c-935-\t{ do_bad,\t\tSIGKILL, SI_KERNEL,\t\"unknown 18\"\t\t\t},\narch/arm64/mm/fault.c:936:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level -1 (translation table walk)\"\t},\narch/arm64/mm/fault.c:937:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 0 (translation table walk)\"\t},\narch/arm64/mm/fault.c:938:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 1 (translation table walk)\"\t},\narch/arm64/mm/fault.c:939:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 2 (translation table walk)\"\t},\narch/arm64/mm/fault.c:940:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 3 (translation table walk)\"\t},\narch/arm64/mm/fault.c:941:\t{ do_sea,\t\tSIGBUS, BUS_OBJERR,\t\"synchronous parity or ECC error\" },\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c-942-\t{ do_bad,\t\tSIGKILL, SI_KERNEL,\t\"unknown 25\"\t\t\t},\narch/arm64/mm/fault.c-943-\t{ do_bad,\t\tSIGKILL, SI_KERNEL,\t\"unknown 26\"\t\t\t},\narch/arm64/mm/fault.c:944:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level -1 synchronous parity error (translation table walk)\"\t},\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c:945:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 0 synchronous parity error (translation table walk)\"\t},\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c:946:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 1 synchronous parity error (translation table walk)\"\t},\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c:947:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 2 synchronous parity error (translation table walk)\"\t},\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c:948:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 3 synchronous parity error (translation table walk)\"\t},\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c-949-\t{ do_bad,\t\tSIGKILL, SI_KERNEL,\t\"unknown 32\"\t\t\t},\n"
} |
| 7/2 | 2026/08/27 23:24 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 4819 output: 29 thoughts: 30 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Investigating `fixup_exception` in the ARM64 Exception Handling Path** Alright, I'm diving into this. The context clearly suggests a potential exception handling scenario within the ARM64 architecture, and the mention of `fixup_exception` immediately directs my attention towards the likely exception table mechanism. My initial thought is to zero in on where that function is defined and used. I'll need to locate `fixup_exception`. Specifically, I'll start in the `arch/arm64/mm/extable.c` file since the extension table is likely where the fixup is implemented. If it's not there, I'll need to widen the search. I expect this function has a very specific purpose related to the control flow or data that is expected to fix an exception that occurred in a specific context. I need to understand how the exception handling interacts with the kernel's memory management on ARM64. The goal is to either confirm my suspicion or quickly identify the correct function definition and understand its overall role in exception processing. From there, I'll dissect the surrounding code to determine its specific function and its relationships to other exception handling functions within the kernel. |
| 8/2 | 2026/08/27 23:24 | tool | grepper |
0mArgs:{
"Expression": "fixup_exception",
"PathPrefix": "arch/arm64"
}Results: {
"Output": "arch/arm64/include/asm/efi.h=16=extern void efi_init(void);\narch/arm64/include/asm/efi.h-17-\narch/arm64/include/asm/efi.h:18:bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg);\narch/arm64/include/asm/efi.h-19-#else\n--\narch/arm64/include/asm/efi.h=22=static inline\narch/arm64/include/asm/efi.h:23:bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)\narch/arm64/include/asm/efi.h-24-{\n--\narch/arm64/include/asm/extable.h=43=bool ex_handler_bpf(const struct exception_table_entry *ex,\n--\narch/arm64/include/asm/extable.h-49-\narch/arm64/include/asm/extable.h:50:bool fixup_exception(struct pt_regs *regs, unsigned long esr);\narch/arm64/include/asm/extable.h-51-#endif\n--\narch/arm64/kernel/efi.c=220=asmlinkage efi_status_t __efi_rt_asm_recover(void);\narch/arm64/kernel/efi.c-221-\narch/arm64/kernel/efi.c:222:bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)\narch/arm64/kernel/efi.c-223-{\n--\narch/arm64/kernel/probes/kprobes.c=301=int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr)\n--\narch/arm64/kernel/probes/kprobes.c-310-\t * must be left alone for the normal page fault handler, including\narch/arm64/kernel/probes/kprobes.c:311:\t * fixup_exception.\narch/arm64/kernel/probes/kprobes.c-312-\t */\n--\narch/arm64/kernel/traps.c=495=void do_el1_bti(struct pt_regs *regs, unsigned long esr)\narch/arm64/kernel/traps.c-496-{\narch/arm64/kernel/traps.c:497:\tif (efi_runtime_fixup_exception(regs, \"BTI violation\")) {\narch/arm64/kernel/traps.c-498-\t\tregs-\u003epstate \u0026= ~PSR_BTYPE_MASK;\n--\narch/arm64/mm/extable.c=69=ex_handler_load_unaligned_zeropad(const struct exception_table_entry *ex,\n--\narch/arm64/mm/extable.c-94-\narch/arm64/mm/extable.c:95:bool fixup_exception(struct pt_regs *regs, unsigned long esr)\narch/arm64/mm/extable.c-96-{\n--\narch/arm64/mm/fault.c=405=static void __do_kernel_fault(unsigned long addr, unsigned long esr,\n--\narch/arm64/mm/fault.c-413-\t */\narch/arm64/mm/fault.c:414:\tif (!is_el1_instruction_abort(esr) \u0026\u0026 fixup_exception(regs, esr))\narch/arm64/mm/fault.c-415-\t\treturn;\n--\narch/arm64/mm/fault.c-450-\narch/arm64/mm/fault.c:451:\tif (efi_runtime_fixup_exception(regs, msg))\narch/arm64/mm/fault.c-452-\t\treturn;\n--\narch/arm64/mm/fault.c=866=static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)\n--\narch/arm64/mm/fault.c-880-\narch/arm64/mm/fault.c:881:\tif (!user_mode(regs) \u0026\u0026 fixup_exception(regs, esr))\narch/arm64/mm/fault.c-882-\t\treturn 0;\n"
} |
| 9/2 | 2026/08/27 23:24 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 6266 output: 39 thoughts: 56 Thoughts: **Investigating the Commit's Purpose** Okay, so I need to understand this commit better. My first instinct is to dive into the Git history. Let me start with something like `git log -1` – that should give me the most recent commit information, right? Or maybe I'll go for the full history, looking at similar commits to see the bigger picture. I need to understand *what* this commit changed and, more importantly, *why*. Context is everything. I'm especially interested in the surrounding circumstances. After reviewing the commit log, line 95 in `arch/arm64/mm/extable.c` is calling to me. That's likely where the core of the change lies, or at least a point of interest to further delve into. So, let's go read that line, and get a better understanding of what the code is doing there. |
| 10/2 | 2026/08/27 23:24 | tool | read-file |
0mArgs:{
"File": "arch/arm64/mm/extable.c",
"FirstLine": 80,
"LineCount": 40
}Results: {
"Contents": " 80:\t\n 81:\t\tdata = *(unsigned long*)addr;\n 82:\t\n 83:\t#ifndef __AARCH64EB__\n 84:\t\tdata \u003e\u003e= 8 * offset;\n 85:\t#else\n 86:\t\tdata \u003c\u003c= 8 * offset;\n 87:\t#endif\n 88:\t\n 89:\t\tpt_regs_write_reg(regs, reg_data, data);\n 90:\t\n 91:\t\tregs-\u003epc = get_ex_fixup(ex);\n 92:\t\treturn true;\n 93:\t}\n 94:\t\n 95:\tbool fixup_exception(struct pt_regs *regs, unsigned long esr)\n 96:\t{\n 97:\t\tconst struct exception_table_entry *ex;\n 98:\t\n 99:\t\tex = search_exception_tables(instruction_pointer(regs));\n 100:\t\tif (!ex)\n 101:\t\t\treturn false;\n 102:\t\n 103:\t\tswitch (ex-\u003etype) {\n 104:\t\tcase EX_TYPE_BPF:\n 105:\t\t\treturn ex_handler_bpf(ex, regs);\n 106:\t\tcase EX_TYPE_UACCESS_ERR_ZERO:\n 107:\t\tcase EX_TYPE_KACCESS_ERR_ZERO:\n 108:\t\t\treturn ex_handler_uaccess_err_zero(ex, regs);\n 109:\t\tcase EX_TYPE_UACCESS_CPY:\n 110:\t\t\treturn ex_handler_uaccess_cpy(ex, regs, esr);\n 111:\t\tcase EX_TYPE_LOAD_UNALIGNED_ZEROPAD:\n 112:\t\t\treturn ex_handler_load_unaligned_zeropad(ex, regs);\n 113:\t\t}\n 114:\t\n 115:\t\tBUG();\n 116:\t}\n"
} |
| 11/2 | 2026/08/27 23:24 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 7053 output: 28 thoughts: 847 Thoughts: **Analyzing the Synchronous External Abort Handling Patch** Okay, so I'm looking at this patch and trying to figure out if it's fuzz-worthy and how it fits into Syzkaller. My initial thought is to understand what `do_sea` in the kernel handles, which is synchronous external aborts. Specifically, I see it's dealing with cases like data aborts, instruction aborts leading to SEAs, translation table walk aborts, and, crucially, kernel memory accesses (think `copy_from_user`, `uaccess`, or `kaccess`). Previously, it looks like if there was an SEA during kernel execution, `do_sea` would just panic through `arm64_notify_die` and `die()`. Now, this patch adds a check within `do_sea` for exception fixups: ```c if (!user_mode(regs) && fixup_exception(regs, esr)) return 0; ``` This is important! Now, if an SEA *during kernel execution* hits an exception-table protected load/store, `fixup_exception()` is called. If there's an exception table entry, `fixup_exception()` fixes the issue by setting the `regs->pc` to the fixup handler and handling the error return, and `do_sea` just returns. Okay, so the prompt is asking me to evaluate whether this is worth fuzzing, based on some specific criteria. Let me recap those criteria: * **Not Fuzzable:** Documentation/Kconfig changes, decorative changes (logging/tracepoints), numeric constants/macros that don't change execution, unreachable code in virtualized environments, vendor-specific PCIe switch/SmartNIC/GPU drivers requiring physical hardware, and teardown callbacks like `.remove`, `.shutdown`, or `pci_unregister_driver` executed only during hot-unplug or sysfs driver unbind operations. * **Fuzzable:** If it modifies reachable core kernel logic, drivers, or architectures, *and* I can verify the code is reachable. If it *is* fuzzable, I need to: 1. Identify functions for `FocusSymbols`, avoiding generic hot-path functions, focusing on non-static, non-inlined API entrypoints. 2. Identify required `CONFIG_` options for testing and put them in `EnableConfigs`. So, it seems this is reachable, but I need to investigate further: Let's check `do_sea` in `arch/arm64/mm/fault.c` to see how the faults are routed and where the fixups are called. I'll need to see what other functions call `do_sea` and how `fault_info` is used. |
| 12/2 | 2026/08/27 23:24 | tool | grepper |
0mArgs:{
"Expression": "fault_info",
"PathPrefix": "arch/arm64"
}Results: {
"Output": "arch/arm64/include/asm/kvm_host.h=309=struct kvm_arch {\n--\narch/arm64/include/asm/kvm_host.h-428-\narch/arm64/include/asm/kvm_host.h:429:struct kvm_vcpu_fault_info {\narch/arm64/include/asm/kvm_host.h-430-\tu64 esr_el2;\t\t/* Hyp Syndrom Register */\n--\narch/arm64/include/asm/kvm_host.h=843=struct kvm_vcpu_arch {\n--\narch/arm64/include/asm/kvm_host.h-873-\t/* Exception Information */\narch/arm64/include/asm/kvm_host.h:874:\tstruct kvm_vcpu_fault_info fault;\narch/arm64/include/asm/kvm_host.h-875-\n--\narch/arm64/kvm/hyp/include/hyp/fault.h=60=static inline bool __hpfar_valid(u64 esr)\n--\narch/arm64/kvm/hyp/include/hyp/fault.h-81-\narch/arm64/kvm/hyp/include/hyp/fault.h:82:static inline bool __get_fault_info(u64 esr, struct kvm_vcpu_fault_info *fault)\narch/arm64/kvm/hyp/include/hyp/fault.h-83-{\n--\narch/arm64/kvm/hyp/include/hyp/switch.h=420=static inline void ___deactivate_traps(struct kvm_vcpu *vcpu)\n--\narch/arm64/kvm/hyp/include/hyp/switch.h-443-\narch/arm64/kvm/hyp/include/hyp/switch.h:444:static inline bool __populate_fault_info(struct kvm_vcpu *vcpu)\narch/arm64/kvm/hyp/include/hyp/switch.h-445-{\narch/arm64/kvm/hyp/include/hyp/switch.h:446:\treturn __get_fault_info(vcpu-\u003earch.fault.esr_el2, \u0026vcpu-\u003earch.fault);\narch/arm64/kvm/hyp/include/hyp/switch.h-447-}\n--\narch/arm64/kvm/hyp/include/hyp/switch.h=837=static inline bool kvm_hyp_handle_memory_fault(struct kvm_vcpu *vcpu,\n--\narch/arm64/kvm/hyp/include/hyp/switch.h-839-{\narch/arm64/kvm/hyp/include/hyp/switch.h:840:\tif (!__populate_fault_info(vcpu))\narch/arm64/kvm/hyp/include/hyp/switch.h-841-\t\treturn true;\n--\narch/arm64/kvm/hyp/nvhe/mem_protect.c=748=void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)\narch/arm64/kvm/hyp/nvhe/mem_protect.c-749-{\narch/arm64/kvm/hyp/nvhe/mem_protect.c:750:\tstruct kvm_vcpu_fault_info fault;\narch/arm64/kvm/hyp/nvhe/mem_protect.c-751-\tu64 esr, addr;\n--\narch/arm64/kvm/hyp/nvhe/mem_protect.c-753-\tesr = read_sysreg_el2(SYS_ESR);\narch/arm64/kvm/hyp/nvhe/mem_protect.c:754:\tif (!__get_fault_info(esr, \u0026fault)) {\narch/arm64/kvm/hyp/nvhe/mem_protect.c-755-\t\t/*\n--\narch/arm64/mm/fault.c-48-\narch/arm64/mm/fault.c:49:struct fault_info {\narch/arm64/mm/fault.c-50-\tint\t(*fn)(unsigned long far, unsigned long esr,\n--\narch/arm64/mm/fault.c-56-\narch/arm64/mm/fault.c:57:static const struct fault_info fault_info[];\narch/arm64/mm/fault.c-58-\narch/arm64/mm/fault.c:59:static inline const struct fault_info *esr_to_fault_info(unsigned long esr)\narch/arm64/mm/fault.c-60-{\narch/arm64/mm/fault.c:61:\treturn fault_info + (esr \u0026 ESR_ELx_FSC);\narch/arm64/mm/fault.c-62-}\n--\narch/arm64/mm/fault.c=98=static void mem_abort_decode(unsigned long esr)\n--\narch/arm64/mm/fault.c-112-\tpr_alert(\" FSC = 0x%02lx: %s\\n\", (esr \u0026 ESR_ELx_FSC),\narch/arm64/mm/fault.c:113:\t\t esr_to_fault_info(esr)-\u003ename);\narch/arm64/mm/fault.c-114-\n--\narch/arm64/mm/fault.c=514=static void do_bad_area(unsigned long far, unsigned long esr,\n--\narch/arm64/mm/fault.c-523-\tif (user_mode(regs)) {\narch/arm64/mm/fault.c:524:\t\tconst struct fault_info *inf = esr_to_fault_info(esr);\narch/arm64/mm/fault.c-525-\n--\narch/arm64/mm/fault.c=601=static int __kprobes do_page_fault(unsigned long far, unsigned long esr,\n--\narch/arm64/mm/fault.c-603-{\narch/arm64/mm/fault.c:604:\tconst struct fault_info *inf;\narch/arm64/mm/fault.c-605-\tstruct mm_struct *mm = current-\u003emm;\n--\narch/arm64/mm/fault.c-794-\narch/arm64/mm/fault.c:795:\tinf = esr_to_fault_info(esr);\narch/arm64/mm/fault.c-796-\tset_thread_esr(addr, esr);\n--\narch/arm64/mm/fault.c=866=static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)\narch/arm64/mm/fault.c-867-{\narch/arm64/mm/fault.c:868:\tconst struct fault_info *inf;\narch/arm64/mm/fault.c-869-\tunsigned long siaddr;\narch/arm64/mm/fault.c-870-\narch/arm64/mm/fault.c:871:\tinf = esr_to_fault_info(esr);\narch/arm64/mm/fault.c-872-\n--\narch/arm64/mm/fault.c=900=static int do_tag_check_fault(unsigned long far, unsigned long esr,\n--\narch/arm64/mm/fault.c-915-\narch/arm64/mm/fault.c:916:static const struct fault_info fault_info[] = {\narch/arm64/mm/fault.c-917-\t{ do_bad,\t\tSIGKILL, SI_KERNEL,\t\"ttbr address size fault\"\t},\n--\narch/arm64/mm/fault.c=983=void do_mem_abort(unsigned long far, unsigned long esr, struct pt_regs *regs)\narch/arm64/mm/fault.c-984-{\narch/arm64/mm/fault.c:985:\tconst struct fault_info *inf = esr_to_fault_info(esr);\narch/arm64/mm/fault.c-986-\tunsigned long addr = untagged_addr(far);\n"
} |
| 13/2 | 2026/08/27 23:24 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 10638 output: 30 thoughts: 39 Thoughts: Okay, let's dive into this. Here's how I'd approach that query, as an expert: **Investigating the `do_mem_abort` Callers in ARM64** Alright, I need to understand what's triggering `do_mem_abort` in the ARM64 architecture. That function is pretty critical – it handles those memory abort exceptions, which are usually a sign of something going wrong. So, I need to know *what*'s calling it to diagnose the source of potential memory issues. My first instinct, given my experience, is to zero in on the direct calls. I'm going to quickly grep the `arch/arm64` directory for the function name `do_mem_abort`. This should give me a list of all the files and lines of code where that function is invoked. That'll be my starting point to examine the call sites and the surrounding code, providing the necessary context. From there, I'll be able to work backward, understand the calling flow and investigate any potential issues. Then, I can start looking at arguments, context and likely culprits. |
| 14/2 | 2026/08/27 23:25 | tool | grepper |
0mArgs:{
"Expression": "do_mem_abort",
"PathPrefix": "arch/arm64"
}Results: {
"Output": "arch/arm64/include/asm/exception.h=53=asmlinkage void asm_exit_to_user_mode(struct pt_regs *regs);\narch/arm64/include/asm/exception.h-54-\narch/arm64/include/asm/exception.h:55:void do_mem_abort(unsigned long far, unsigned long esr, struct pt_regs *regs);\narch/arm64/include/asm/exception.h-56-void do_el0_undef(struct pt_regs *regs, unsigned long esr);\n--\narch/arm64/kernel/entry-common.c=315=static void noinstr el1_abort(struct pt_regs *regs, unsigned long esr)\n--\narch/arm64/kernel/entry-common.c-321-\tlocal_daif_inherit(regs);\narch/arm64/kernel/entry-common.c:322:\tdo_mem_abort(far, esr, regs);\narch/arm64/kernel/entry-common.c-323-\tarm64_exit_to_kernel_mode(regs, state);\n--\narch/arm64/kernel/entry-common.c=546=static void noinstr el0_da(struct pt_regs *regs, unsigned long esr)\n--\narch/arm64/kernel/entry-common.c-551-\tlocal_daif_restore(DAIF_PROCCTX);\narch/arm64/kernel/entry-common.c:552:\tdo_mem_abort(far, esr, regs);\narch/arm64/kernel/entry-common.c-553-\tarm64_exit_to_user_mode(regs);\n--\narch/arm64/kernel/entry-common.c=556=static void noinstr el0_ia(struct pt_regs *regs, unsigned long esr)\n--\narch/arm64/kernel/entry-common.c-569-\tlocal_daif_restore(DAIF_PROCCTX);\narch/arm64/kernel/entry-common.c:570:\tdo_mem_abort(far, esr, regs);\narch/arm64/kernel/entry-common.c-571-\tarm64_exit_to_user_mode(regs);\n--\narch/arm64/mm/fault.c=916=static const struct fault_info fault_info[] = {\n--\narch/arm64/mm/fault.c-982-\narch/arm64/mm/fault.c:983:void do_mem_abort(unsigned long far, unsigned long esr, struct pt_regs *regs)\narch/arm64/mm/fault.c-984-{\n--\narch/arm64/mm/fault.c-1000-}\narch/arm64/mm/fault.c:1001:NOKPROBE_SYMBOL(do_mem_abort);\narch/arm64/mm/fault.c-1002-\n"
} |
| 15/2 | 2026/08/27 23:25 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 11697 output: 28 thoughts: 1446 Thoughts: **Focusing on Exception Handling in ARM64 Kernel Memory Access** Alright, let's break this down. My goal is to identify key functions for fuzzing, specifically related to how the kernel handles memory access exceptions on ARM64. The context is an EL1 abort, where kernel code accessing memory triggers a synchronous abort. This can stem from `copy_from_user`, exception-handled loads/stores, or other operations. The flow is: `el1_abort` -> `do_mem_abort` -> `inf->fn(far, esr, regs)`. Critically, if it's a page fault, `do_page_fault` kicks in. Kernel-mode page faults eventually lead to `__do_kernel_fault` and `fixup_exception`. Now, the interesting bit: Synchronous External Aborts (SEA) with FSC = 0x10 (or translation table walk SEAs) are handled by `do_sea`. Previously, `do_sea` only had a check for user mode and APEI claims. Now, there is a check on non-user mode execution and `fixup_exception` is called. The key question is, is this reachable in QEMU, GCE, or fuzzing? Yes, on ARM64, any EL1 abort triggering SEA on an address accessed with fixup handlers (think uaccess on an unmapped guest physical address or SEA injection via PCIe/devmem, etc.) will execute this new path: `do_sea` -> `fixup_exception`. That's the core focus: exception handling for kernel memory accesses! Okay, so I need to decide on FocusSymbols. I know I want to avoid generic hot-path functions. `do_mem_abort` handles all data and instruction aborts (page faults, etc.) so that's a *very* generic handler. This isn't the function I'm looking for. `do_sea` is static in `fault.c`, and I'm aware that static functions are often inlined by the compiler, potentially making them less suitable for direct fuzzing targets if they lack a distinct symbol address. However, because `do_sea` is in the `fault_info` table, it is not inlined and has an associated symbol. `fixup_exception` looks promising: it's not a generic hot path. It is only called when an exception/fault happens in kernel mode. Also, I see it's defined in `arch/arm64/mm/extable.c`, and declared in `arch/arm64/include/asm/extable.h`. This is only triggered for EL1 exceptions (kernel mode faults). I need to confirm the key functions that should be included in `FocusSymbols`. I reviewed the code around `do_sea`. There are no conditional compiles. The code is always built with `CONFIG_ARM64=y`. Therefore, the critical functions to focus on are `do_sea` and `fixup_exception` as these are both specific and are not generic hot-path functions. However, `do_mem_abort` is definitely NOT the focus as it is too generic. |
| 16/2 | 2026/08/27 23:25 | tool | grepper |
0mArgs:{
"Expression": "fault.o",
"PathPrefix": "arch/arm64"
}Results: {
"Output": "arch/arm64/Kconfig=1273=config FUJITSU_ERRATUM_010001\n--\narch/arm64/Kconfig-1279-\t accesses may cause undefined fault (Data abort, DFSC=0b111111).\narch/arm64/Kconfig:1280:\t This fault occurs under a specific hardware condition when a\narch/arm64/Kconfig-1281-\t load/store instruction performs an address translation using:\n--\narch/arm64/boot/dts/allwinner/sun50i-h64-remix-mini-pc.dts=235=\u0026reg_dcdc5 {\n--\narch/arm64/boot/dts/allwinner/sun50i-h64-remix-mini-pc.dts-241-\narch/arm64/boot/dts/allwinner/sun50i-h64-remix-mini-pc.dts:242:/* Deviates from the reset default of 1.1V. */\narch/arm64/boot/dts/allwinner/sun50i-h64-remix-mini-pc.dts-243-\u0026reg_dcdc6 {\n--\narch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts=48=\t\tled-1 {\n--\narch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts-51-\t\t\tmax-brightness = \u003c255\u003e;\narch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts:52:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts-53-\t\t};\n--\narch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts=88=\t\tled-1 {\n--\narch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts-91-\t\t\tmax-brightness = \u003c255\u003e;\narch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts:92:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts-93-\t\t};\n--\narch/arm64/boot/dts/amlogic/meson-libretech-cottonwood.dtsi=81=\t\tled {\n--\narch/arm64/boot/dts/amlogic/meson-libretech-cottonwood.dtsi-83-\t\t\tfunction = LED_FUNCTION_STATUS;\narch/arm64/boot/dts/amlogic/meson-libretech-cottonwood.dtsi:84:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/amlogic/meson-libretech-cottonwood.dtsi-85-\t\t\tmax-brightness = \u003c255\u003e;\n--\narch/arm64/boot/dts/amlogic/meson-sm1-sei610.dts=116=\t\tled-2 {\n--\narch/arm64/boot/dts/amlogic/meson-sm1-sei610.dts-119-\t\t\tmax-brightness = \u003c255\u003e;\narch/arm64/boot/dts/amlogic/meson-sm1-sei610.dts:120:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/amlogic/meson-sm1-sei610.dts-121-\t\t\tactive-low;\n--\narch/arm64/boot/dts/broadcom/bcmbca/bcm4906-zyxel-ex3510b.dts=70=\tled@a {\n--\narch/arm64/boot/dts/broadcom/bcmbca/bcm4906-zyxel-ex3510b.dts-73-\t\tcolor = \u003cLED_COLOR_ID_GREEN\u003e;\narch/arm64/boot/dts/broadcom/bcmbca/bcm4906-zyxel-ex3510b.dts:74:\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/broadcom/bcmbca/bcm4906-zyxel-ex3510b.dts-75-\t};\n--\narch/arm64/boot/dts/freescale/fsl-ls1012a-tqmls1012al-mbls1012al.dts=70=\t\tled-1 {\n--\narch/arm64/boot/dts/freescale/fsl-ls1012a-tqmls1012al-mbls1012al.dts-73-\t\t\tgpios = \u003c\u0026gpio_exp_3p3v 15 GPIO_ACTIVE_LOW\u003e;\narch/arm64/boot/dts/freescale/fsl-ls1012a-tqmls1012al-mbls1012al.dts:74:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/freescale/fsl-ls1012a-tqmls1012al-mbls1012al.dts-75-\t\t};\n--\narch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-kbox-a-230-ls.dts=30=\t\tpower-led {\narch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-kbox-a-230-ls.dts:31:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-kbox-a-230-ls.dts-32-\t\t\tfunction = LED_FUNCTION_POWER;\n--\narch/arm64/boot/dts/freescale/fsl-ls1028a-tqmls1028a-mbls1028a.dts=45=\t\tled-1 {\n--\narch/arm64/boot/dts/freescale/fsl-ls1028a-tqmls1028a-mbls1028a.dts-49-\t\t\tgpios = \u003c\u0026gpio_exp_3v3 14 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/freescale/fsl-ls1028a-tqmls1028a-mbls1028a.dts:50:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/freescale/fsl-ls1028a-tqmls1028a-mbls1028a.dts-51-\t\t};\n--\narch/arm64/boot/dts/freescale/imx8mp-hummingboard-iiot.dts=107=\tspi_mux: mux-controller-1 {\narch/arm64/boot/dts/freescale/imx8mp-hummingboard-iiot.dts-108-\t\tcompatible = \"gpio-mux\";\narch/arm64/boot/dts/freescale/imx8mp-hummingboard-iiot.dts:109:\t\t/* default on-board */\narch/arm64/boot/dts/freescale/imx8mp-hummingboard-iiot.dts-110-\t\tidle-state = \u003c0\u003e;\n--\narch/arm64/boot/dts/freescale/imx8mp-hummingboard-iiot.dts=119=\tuart3_uart4_b2b_mux: mux-controller-2 {\narch/arm64/boot/dts/freescale/imx8mp-hummingboard-iiot.dts-120-\t\tcompatible = \"gpio-mux\";\narch/arm64/boot/dts/freescale/imx8mp-hummingboard-iiot.dts:121:\t\t/* default on-board */\narch/arm64/boot/dts/freescale/imx8mp-hummingboard-iiot.dts-122-\t\tidle-state = \u003c0\u003e;\n--\narch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl.dts=116=\t\tled-0 {\n--\narch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl.dts-120-\t\t\tgpios = \u003c\u0026gpio5 5 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl.dts:121:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl.dts-122-\t\t};\n--\narch/arm64/boot/dts/freescale/imx91-tqma9131-mba91xxca.dts=101=\t\tled-1 {\n--\narch/arm64/boot/dts/freescale/imx91-tqma9131-mba91xxca.dts-104-\t\t\tgpios = \u003c\u0026expander2 6 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/freescale/imx91-tqma9131-mba91xxca.dts:105:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/freescale/imx91-tqma9131-mba91xxca.dts-106-\t\t};\n--\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba91xxca.dts=101=\t\tled-1 {\n--\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba91xxca.dts-104-\t\t\tgpios = \u003c\u0026expander2 6 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba91xxca.dts:105:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba91xxca.dts-106-\t\t};\n--\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba93xxca.dts=107=\t\tled-1 {\n--\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba93xxca.dts-110-\t\t\tgpios = \u003c\u0026expander2 6 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba93xxca.dts:111:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba93xxca.dts-112-\t\t};\n--\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba93xxla.dts=98=\t\tled-1 {\n--\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba93xxla.dts-101-\t\t\tgpios = \u003c\u0026expander2 6 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba93xxla.dts:102:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/freescale/imx93-tqma9352-mba93xxla.dts-103-\t\t};\n--\narch/arm64/boot/dts/freescale/mba8mx.dtsi=71=\t\tled1 {\n--\narch/arm64/boot/dts/freescale/mba8mx.dtsi-73-\t\t\tgpios = \u003c\u0026gpio1 0 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/freescale/mba8mx.dtsi:74:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/freescale/mba8mx.dtsi-75-\t\t};\n--\narch/arm64/boot/dts/freescale/mba8xx.dtsi=68=\t\tled1 {\n--\narch/arm64/boot/dts/freescale/mba8xx.dtsi-71-\t\t\tgpios = \u003c\u0026expander 1 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/freescale/mba8xx.dtsi:72:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/freescale/mba8xx.dtsi-73-\t\t};\n--\narch/arm64/boot/dts/marvell/armada-3720-atlas-v5.dts=36=\t\tled {\n--\narch/arm64/boot/dts/marvell/armada-3720-atlas-v5.dts-39-\t\t\tcolor = \u003cLED_COLOR_ID_RED\u003e;\narch/arm64/boot/dts/marvell/armada-3720-atlas-v5.dts:40:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/marvell/armada-3720-atlas-v5.dts-41-\t\t};\n--\narch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts=38=\t\tled {\n--\narch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts-40-\t\t\tgpios = \u003c\u0026gpiosb 21 GPIO_ACTIVE_LOW\u003e;\narch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts:41:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts-42-\t\t};\n--\narch/arm64/boot/dts/marvell/armada-37xx.dtsi=23=\treserved-memory {\n--\narch/arm64/boot/dts/marvell/armada-37xx.dtsi-28-\t\t/*\narch/arm64/boot/dts/marvell/armada-37xx.dtsi:29:\t\t * The PSCI firmware region depicted below is the default one\narch/arm64/boot/dts/marvell/armada-37xx.dtsi-30-\t\t * and should be updated by the bootloader.\n--\narch/arm64/boot/dts/qcom/sdm450-lenovo-tbx605f.dts=49=\tbacklight: gpio-backlight {\n--\narch/arm64/boot/dts/qcom/sdm450-lenovo-tbx605f.dts-53-\narch/arm64/boot/dts/qcom/sdm450-lenovo-tbx605f.dts:54:\t\tdefault-on;\narch/arm64/boot/dts/qcom/sdm450-lenovo-tbx605f.dts-55-\n--\narch/arm64/boot/dts/qcom/talos-evk-lvds-auo,g133han01.dtso=11=\tbacklight: backlight {\n--\narch/arm64/boot/dts/qcom/talos-evk-lvds-auo,g133han01.dtso-13-\t\tgpios = \u003c\u0026tlmm 115 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/qcom/talos-evk-lvds-auo,g133han01.dtso:14:\t\tdefault-on;\narch/arm64/boot/dts/qcom/talos-evk-lvds-auo,g133han01.dtso-15-\t};\n--\narch/arm64/boot/dts/rockchip/px30-cobra.dtsi=120=\u0026emmc {\n--\narch/arm64/boot/dts/rockchip/px30-cobra.dtsi-124-\t * For hs200 support, U-Boot would have to set the RK809 DCDC4\narch/arm64/boot/dts/rockchip/px30-cobra.dtsi:125:\t * rail to 1.8V from the default of 3.0V. It doesn't do that on\narch/arm64/boot/dts/rockchip/px30-cobra.dtsi-126-\t * devices out in the field, so disable hs200.\n--\narch/arm64/boot/dts/rockchip/px30-firefly-jd4-core-mb.dts=64=\t\tgreen-led {\n--\narch/arm64/boot/dts/rockchip/px30-firefly-jd4-core-mb.dts-69-\t\t\tlabel = \"px30-mb-jd4:blue:diy\";\narch/arm64/boot/dts/rockchip/px30-firefly-jd4-core-mb.dts:70:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/px30-firefly-jd4-core-mb.dts-71-\t\t};\n--\narch/arm64/boot/dts/rockchip/px30-pp1516.dtsi=148=\u0026emmc {\n--\narch/arm64/boot/dts/rockchip/px30-pp1516.dtsi-152-\t * For hs200 support, U-Boot would have to set the RK809 DCDC4\narch/arm64/boot/dts/rockchip/px30-pp1516.dtsi:153:\t * rail to 1.8V from the default of 3.0V. It doesn't do that on\narch/arm64/boot/dts/rockchip/px30-pp1516.dtsi-154-\t * devices out in the field, so disable hs200.\n--\narch/arm64/boot/dts/rockchip/rk3308-bpi-p2-pro.dts=52=\t\tblue-led {\n--\narch/arm64/boot/dts/rockchip/rk3308-bpi-p2-pro.dts-57-\t\t\tlabel = \"blue:power\";\narch/arm64/boot/dts/rockchip/rk3308-bpi-p2-pro.dts:58:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3308-bpi-p2-pro.dts-59-\t\t};\n--\narch/arm64/boot/dts/rockchip/rk3308-roc-cc.dts=37=\t\tpower_led: led-0 {\narch/arm64/boot/dts/rockchip/rk3308-roc-cc.dts-38-\t\t\tlabel = \"firefly:red:power\";\narch/arm64/boot/dts/rockchip/rk3308-roc-cc.dts:39:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3308-roc-cc.dts-40-\t\t\tdefault-state = \"on\";\n--\narch/arm64/boot/dts/rockchip/rk3399-hugsun-x99.dts=51=\t\tpower_led: led-0 {\n--\narch/arm64/boot/dts/rockchip/rk3399-hugsun-x99.dts-54-\t\t\tdefault-state = \"on\";\narch/arm64/boot/dts/rockchip/rk3399-hugsun-x99.dts:55:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3399-hugsun-x99.dts-56-\t\t};\n--\narch/arm64/boot/dts/rockchip/rk3528-armsom-sige1.dts=55=\t\tled-1 {\n--\narch/arm64/boot/dts/rockchip/rk3528-armsom-sige1.dts-59-\t\t\tgpios = \u003c\u0026gpio3 RK_PB2 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/rockchip/rk3528-armsom-sige1.dts:60:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3528-armsom-sige1.dts-61-\t\t};\n--\narch/arm64/boot/dts/rockchip/rk3528-nanopi-zero2.dts=67=\t\tled-1 {\n--\narch/arm64/boot/dts/rockchip/rk3528-nanopi-zero2.dts-71-\t\t\tgpios = \u003c\u0026gpio4 RK_PB1 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/rockchip/rk3528-nanopi-zero2.dts:72:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3528-nanopi-zero2.dts-73-\t\t};\n--\narch/arm64/boot/dts/rockchip/rk3566-bigtreetech-cb2.dtsi=50=\t\tled-0 {\n--\narch/arm64/boot/dts/rockchip/rk3566-bigtreetech-cb2.dtsi-53-\t\t\tgpios = \u003c\u0026gpio4 RK_PA1 GPIO_ACTIVE_LOW\u003e;\narch/arm64/boot/dts/rockchip/rk3566-bigtreetech-cb2.dtsi:54:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3566-bigtreetech-cb2.dtsi-55-\t\t\tpinctrl-names = \"default\";\n--\narch/arm64/boot/dts/rockchip/rk3566-odroid-m1s.dts=41=\t\tled_pwr: led-0 {\n--\narch/arm64/boot/dts/rockchip/rk3566-odroid-m1s.dts-45-\t\t\tgpios = \u003c\u0026gpio0 RK_PC6 GPIO_ACTIVE_LOW\u003e;\narch/arm64/boot/dts/rockchip/rk3566-odroid-m1s.dts:46:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3566-odroid-m1s.dts-47-\t\t};\n--\narch/arm64/boot/dts/rockchip/rk3568-hinlink-opc.dtsi=69=\t\tled-2 {\n--\narch/arm64/boot/dts/rockchip/rk3568-hinlink-opc.dtsi-72-\t\t\tgpios = \u003c\u0026gpio3 RK_PB0 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/rockchip/rk3568-hinlink-opc.dtsi:73:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3568-hinlink-opc.dtsi-74-\t\t};\n--\narch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts=62=\t\tled_power: led-0 {\n--\narch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts-66-\t\t\tdefault-state = \"keep\";\narch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts:67:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts-68-\t\t\tpinctrl-names = \"default\";\n--\narch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts=53=\t\tred_led: red-led {\n--\narch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts-56-\t\t\tgpios = \u003c\u0026gpio4 RK_PB1 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts:57:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts-58-\t\t};\n--\narch/arm64/boot/dts/rockchip/rk3588-roc-rt.dts=124=\t\tpower_led {\narch/arm64/boot/dts/rockchip/rk3588-roc-rt.dts-125-\t\t\tgpios = \u003c\u0026gpio1 RK_PD3 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/rockchip/rk3588-roc-rt.dts:126:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3588-roc-rt.dts-127-\t\t};\n--\narch/arm64/boot/dts/rockchip/rk3588s-khadas-edge2.dts=70=\t\tgreen_led: led-1 {\n--\narch/arm64/boot/dts/rockchip/rk3588s-khadas-edge2.dts-74-\t\t\tfunction = LED_FUNCTION_POWER;\narch/arm64/boot/dts/rockchip/rk3588s-khadas-edge2.dts:75:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3588s-khadas-edge2.dts-76-\t\t\tmax-brightness = \u003c255\u003e;\n--\narch/arm64/boot/dts/rockchip/rk3588s-odroid-m2.dts=42=\t\tled_pwr: led-0 {\n--\narch/arm64/boot/dts/rockchip/rk3588s-odroid-m2.dts-46-\t\t\tgpios = \u003c\u0026gpio1 RK_PB5 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/rockchip/rk3588s-odroid-m2.dts:47:\t\t\tlinux,default-trigger = \"default-on\";\narch/arm64/boot/dts/rockchip/rk3588s-odroid-m2.dts-48-\t\t};\n--\narch/arm64/boot/dts/st/stm32mp235f-dk.dts=109=\tpanel_lvds_backlight: backlight {\n--\narch/arm64/boot/dts/st/stm32mp235f-dk.dts-111-\t\tgpios = \u003c\u0026gpioi 4 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/st/stm32mp235f-dk.dts:112:\t\tdefault-on;\narch/arm64/boot/dts/st/stm32mp235f-dk.dts-113-\t\tstatus = \"okay\";\n--\narch/arm64/boot/dts/st/stm32mp257f-dk.dts=116=\tpanel_lvds_backlight: backlight {\n--\narch/arm64/boot/dts/st/stm32mp257f-dk.dts-118-\t\tgpios = \u003c\u0026gpioi 4 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/st/stm32mp257f-dk.dts:119:\t\tdefault-on;\narch/arm64/boot/dts/st/stm32mp257f-dk.dts-120-\t\tstatus = \"okay\";\n--\narch/arm64/boot/dts/st/stm32mp257f-ev1.dts=140=\tpanel_lvds_backlight: backlight {\n--\narch/arm64/boot/dts/st/stm32mp257f-ev1.dts-142-\t\tgpios = \u003c\u0026gpioi 5 GPIO_ACTIVE_HIGH\u003e;\narch/arm64/boot/dts/st/stm32mp257f-ev1.dts:143:\t\tdefault-on;\narch/arm64/boot/dts/st/stm32mp257f-ev1.dts-144-\t\tstatus = \"okay\";\n--\narch/arm64/include/asm/brk-imm.h-15- * Allowed values for kgdb are 0x400 - 0x7ff\narch/arm64/include/asm/brk-imm.h:16: * 0x100: for triggering a fault on purpose (reserved)\narch/arm64/include/asm/brk-imm.h-17- * 0x400: for dynamic BRK instruction\n--\narch/arm64/include/asm/insn-def.h-17-/*\narch/arm64/include/asm/insn-def.h:18: * BRK instruction for provoking a fault on purpose\narch/arm64/include/asm/insn-def.h-19- * Unlike kgdb, #imm16 value with unallocated handler is used for faulting.\n--\narch/arm64/include/asm/kvm_emulate.h=480=static inline bool kvm_is_write_fault(struct kvm_vcpu *vcpu)\n--\narch/arm64/include/asm/kvm_emulate.h-483-\t\t/*\narch/arm64/include/asm/kvm_emulate.h:484:\t\t * Only a permission fault on a S1PTW should be\narch/arm64/include/asm/kvm_emulate.h-485-\t\t * considered as a write. Otherwise, page tables baked\n--\narch/arm64/include/asm/mte-kasan.h=60=static inline void mte_enable_tco(void)\n--\narch/arm64/include/asm/mte-kasan.h-68- * since the sync mode generates exceptions synchronously and the\narch/arm64/include/asm/mte-kasan.h:69: * nofault or load_unaligned_zeropad can handle them.\narch/arm64/include/asm/mte-kasan.h-70- */\n--\narch/arm64/kernel/fpsimd.c=867=int vec_set_vector_length(struct task_struct *task, enum vec_type type,\n--\narch/arm64/kernel/fpsimd.c-898-\telse\narch/arm64/kernel/fpsimd.c:899:\t\t/* Reset VL to system default on next exec: */\narch/arm64/kernel/fpsimd.c-900-\t\ttask_set_vl_onexec(task, type, 0);\n--\narch/arm64/kernel/hw_breakpoint.c=631=void do_breakpoint(unsigned long esr, struct pt_regs *regs)\n--\narch/arm64/kernel/hw_breakpoint.c-666-\t\t/* Do we need to handle the stepping? */\narch/arm64/kernel/hw_breakpoint.c:667:\t\tif (is_default_overflow_handler(bp))\narch/arm64/kernel/hw_breakpoint.c-668-\t\t\tstep = 1;\n--\narch/arm64/kernel/hw_breakpoint.c=741=static int watchpoint_report(struct perf_event *wp, unsigned long addr,\n--\narch/arm64/kernel/hw_breakpoint.c-743-{\narch/arm64/kernel/hw_breakpoint.c:744:\tint step = is_default_overflow_handler(wp);\narch/arm64/kernel/hw_breakpoint.c-745-\tstruct arch_hw_breakpoint *info = counter_arch_bp(wp);\n--\narch/arm64/kernel/mte.c=204=static void mte_update_sctlr_user(struct task_struct *task)\n--\narch/arm64/kernel/mte.c-225-\t * set bits and map into register values determines our\narch/arm64/kernel/mte.c:226:\t * default order.\narch/arm64/kernel/mte.c-227-\t */\n--\narch/arm64/kernel/probes/kprobes.c=301=int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr)\n--\narch/arm64/kernel/probes/kprobes.c-322-\t\t * single-stepping if the faulting PC points to the\narch/arm64/kernel/probes/kprobes.c:323:\t\t * current kprobe's XOL instruction. If the fault occurred\narch/arm64/kernel/probes/kprobes.c-324-\t\t * elsewhere (e.g. in perf or tracing code invoked from the\n--\narch/arm64/kvm/Makefile=16=kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \\\narch/arm64/kvm/Makefile:17:\t inject_fault.o va_layout.o handle_exit.o config.o \\\narch/arm64/kvm/Makefile-18-\t guest.o debug.o reset.o sys_regs.o stacktrace.o \\\n--\narch/arm64/kvm/arm.c=60=enum kvm_wfx_trap_policy {\narch/arm64/kvm/arm.c:61:\tKVM_WFX_NOTRAP_SINGLE_TASK, /* Default option */\narch/arm64/kvm/arm.c-62-\tKVM_WFX_NOTRAP,\n--\narch/arm64/kvm/arm.c=1644=static int kvm_setup_vcpu(struct kvm_vcpu *vcpu)\n--\narch/arm64/kvm/arm.c-1650-\t * When the vCPU has a PMU, but no PMU is set for the guest\narch/arm64/kvm/arm.c:1651:\t * yet, set the default one.\narch/arm64/kvm/arm.c-1652-\t */\n--\narch/arm64/kvm/hyp/include/hyp/fault.h=60=static inline bool __hpfar_valid(u64 esr)\n--\narch/arm64/kvm/hyp/include/hyp/fault.h-63-\t * CPUs affected by ARM erratum #834220 may incorrectly report a\narch/arm64/kvm/hyp/include/hyp/fault.h:64:\t * stage-2 translation fault when a stage-1 permission fault occurs.\narch/arm64/kvm/hyp/include/hyp/fault.h-65-\t *\n--\narch/arm64/kvm/hyp/nvhe/pkvm.c=1053=static u64 __pkvm_memshare_page_req(struct kvm_vcpu *vcpu, u64 ipa)\n--\narch/arm64/kvm/hyp/nvhe/pkvm.c-1056-\narch/arm64/kvm/hyp/nvhe/pkvm.c:1057:\t/* Fake up a data abort (level 3 translation fault on write) */\narch/arm64/kvm/hyp/nvhe/pkvm.c-1058-\tvcpu-\u003earch.fault.esr_el2 = (ESR_ELx_EC_DABT_LOW \u003c\u003c ESR_ELx_EC_SHIFT) |\n--\narch/arm64/kvm/mmu.c=2247=int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)\n--\narch/arm64/kvm/mmu.c-2291-\narch/arm64/kvm/mmu.c:2292:\t/* Check the stage-2 fault is trans. fault or write fault */\narch/arm64/kvm/mmu.c-2293-\tif (!esr_fsc_is_translation_fault(esr) \u0026\u0026\n--\narch/arm64/kvm/pmu-emul.c=1043=static void kvm_arm_set_pmu(struct kvm *kvm, struct arm_pmu *arm_pmu)\n--\narch/arm64/kvm/pmu-emul.c-1051-/**\narch/arm64/kvm/pmu-emul.c:1052: * kvm_arm_set_default_pmu - No PMU set, get the default one.\narch/arm64/kvm/pmu-emul.c-1053- * @kvm: The kvm pointer\n--\narch/arm64/mm/Makefile-1-# SPDX-License-Identifier: GPL-2.0\narch/arm64/mm/Makefile:2:obj-y\t\t\t\t:= dma-mapping.o extable.o fault.o init.o \\\narch/arm64/mm/Makefile-3-\t\t\t\t cache.o copypage.o flush.o \\\n--\narch/arm64/mm/contpte.c=69=static void contpte_convert(struct mm_struct *mm, unsigned long addr,\n--\narch/arm64/mm/contpte.c-157-\t * If both the old single (RW,n) and new contiguous (RO,c) TLB entries\narch/arm64/mm/contpte.c:158:\t * are present, and a write is made to this address, do we fault or\narch/arm64/mm/contpte.c-159-\t * is the write permitted (via amalgamation)?\n--\narch/arm64/mm/extable.c=14=static bool cpy_faulted_on_uaccess(const struct exception_table_entry *ex,\n--\narch/arm64/mm/extable.c-17-\tbool uaccess_is_write = FIELD_GET(EX_DATA_UACCESS_WRITE, ex-\u003edata);\narch/arm64/mm/extable.c:18:\tbool fault_on_write = esr \u0026 ESR_ELx_WNR;\narch/arm64/mm/extable.c-19-\narch/arm64/mm/extable.c:20:\treturn uaccess_is_write == fault_on_write;\narch/arm64/mm/extable.c-21-}\n--\narch/arm64/mm/fault.c=601=static int __kprobes do_page_fault(unsigned long far, unsigned long esr,\n--\narch/arm64/mm/fault.c-790-\t\t */\narch/arm64/mm/fault.c:791:\t\tpagefault_out_of_memory();\narch/arm64/mm/fault.c-792-\t\treturn 0;\n"
} |
| 17/2 | 2026/08/27 23:25 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 24211 output: 31 thoughts: 262 Thoughts: **My Analysis of ARM64 Fault Handling** Okay, so I'm looking at how the ARM64 kernel handles memory faults. I see that `fault.o` and `extable.o` are built alongside `dma-mapping.o` and others, all part of the standard build process via `obj-y`. The architecture config is `CONFIG_ARM64` – nothing too unusual here unless we're dealing with something specific, so no need to delve into specific EnableConfigs, `[]` is fine and `IS_ENABLED(CONFIG_ARM64)` is implied. Now, I need to understand the control flow; I should check out `fixup_exception`, `do_sea`, and `do_mem_abort`. I'll also glance through other symbols and configs. Aha! Looking at `fault.c` directly, I can see some relevant `CONFIG_` options in play: `CONFIG_COMPAT_ALIGNMENT_FIXUPS` – that's for handling alignment faults, obviously. `CONFIG_HARDEN_EL2_VECTORS` isn't pertinent in this context. And then, there's `CONFIG_ACPI_APEI_SEA` and `CONFIG_ACPI_APEI`. That's interesting, as that involves `apei_claim_sea`. I should check out `apei_claim_sea` in `arch/arm64` to see how that's tied into the fault handling process. |
| 18/2 | 2026/08/27 23:25 | tool | grepper |
0mArgs:{
"Expression": "apei_claim_sea",
"PathPrefix": "arch/arm64"
}Results: {
"Output": "arch/arm64/include/asm/acpi.h=120=void __init acpi_init_cpus(void);\narch/arm64/include/asm/acpi.h:121:int apei_claim_sea(struct pt_regs *regs);\narch/arm64/include/asm/acpi.h-122-#else\narch/arm64/include/asm/acpi.h=123=static inline void acpi_init_cpus(void) { }\narch/arm64/include/asm/acpi.h:124:static inline int apei_claim_sea(struct pt_regs *regs) { return -ENOENT; }\narch/arm64/include/asm/acpi.h-125-#endif /* CONFIG_ACPI */\n--\narch/arm64/kernel/acpi.c=295=void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size)\n--\narch/arm64/kernel/acpi.c-388- */\narch/arm64/kernel/acpi.c:389:int apei_claim_sea(struct pt_regs *regs)\narch/arm64/kernel/acpi.c-390-{\n--\narch/arm64/kvm/mmu.c=2185=int kvm_handle_guest_sea(struct kvm_vcpu *vcpu)\n--\narch/arm64/kvm/mmu.c-2200-\t * Give APEI the opportunity to claim the abort before handling it\narch/arm64/kvm/mmu.c:2201:\t * within KVM. apei_claim_sea() expects to be called with IRQs enabled.\narch/arm64/kvm/mmu.c-2202-\t */\narch/arm64/kvm/mmu.c-2203-\tlockdep_assert_irqs_enabled();\narch/arm64/kvm/mmu.c:2204:\tif (apei_claim_sea(NULL) == 0)\narch/arm64/kvm/mmu.c-2205-\t\treturn 1;\n--\narch/arm64/mm/fault.c=866=static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)\n--\narch/arm64/mm/fault.c-872-\narch/arm64/mm/fault.c:873:\tif (user_mode(regs) \u0026\u0026 apei_claim_sea(regs) == 0) {\narch/arm64/mm/fault.c-874-\t\t/*\n"
} |
| 19/2 | 2026/08/27 23:25 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 25503 output: 89 thoughts: 413 Thoughts: **My Analysis of this Patch** Okay, let's break this down. This patch is modifying `arch/arm64/mm/fault.c`. Specifically, it's adding a check within `do_sea()`, the Synchronous External Abort (SEA) handler, like this: ```c if (!user_mode(regs) && fixup_exception(regs, esr)) return 0; ``` Essentially, if a SEA happens in kernel mode (EL1), instead of immediately crashing – as would happen with `arm64_notify_die` – the code is now checking if `fixup_exception()` can handle it. If `fixup_exception` returns true, the exception is "fixed up" (handled). This is interesting. Is this fuzzing-worthy? Absolutely. This is core ARM64 memory abort/exception handling. A potential vulnerability here could lead to some nasty exploits, if a bad actor can trigger the code path. So, the key symbols here are `fixup_exception` (which, importantly, is a global, non-static function defined in `arch/arm64/mm/extable.c`) and `do_sea` (the SEA handler this patch modifies). `do_sea` is static but is used in `fault_info` table, so it *should* be address-taken and accessible in kallsyms if CONFIG_KALLSYMS is enabled. I should probably keep an eye on `do_mem_abort` too, as it's the general entry point for memory aborts. And thankfully, no special Kconfig options are required because this is unconditional in `arch/arm64/mm/fault.c`. This makes things much simpler. So, to summarize: * **WorthFuzzing**: True * **FocusSymbols**: `["fixup_exception", "do_sea"]` * **EnableConfigs**: `[]` The reasoning? It's all about probing the critical kernel exception handling logic. This looks good. Ready to invoke `set-results`. |
| 20/2 | 2026/08/27 23:25 | tool | set-results |
0mArgs:{
"EnableConfigs": [],
"FocusSymbols": [
"fixup_exception",
"do_sea"
],
"Reasoning": "The patch allows kernel-mode synchronous external aborts (SEA) to be recovered using exception fixup tables instead of immediately panicking. This modifies core ARM64 fault handling logic reachable during kernel memory accesses that fault with SEA.",
"WorthFuzzing": true
}Results: {
"EnableConfigs": null,
"FocusSymbols": [
"fixup_exception",
"do_sea"
],
"Reasoning": "The patch allows kernel-mode synchronous external aborts (SEA) to be recovered using exception fixup tables instead of immediately panicking. This modifies core ARM64 fault handling logic reachable during kernel memory accesses that fault with SEA.",
"WorthFuzzing": true
} |
| 21/1 | 2026/08/27 23:25 | action | If |
1mArgs:{
"WorthFuzzing": true
}Results: null |
| 22/2 | 2026/08/27 23:25 | agent | kmsan-evaluator |
1mModel:core Args: null Results: {
"KMSANReasoning": "The patch modifies `do_sea()` in `arch/arm64/mm/fault.c` to attempt exception fixup via `fixup_exception()` when a Synchronous External Abort (SEA) occurs in kernel mode (`!user_mode(regs)`), allowing graceful recovery (e.g., returning -EFAULT for uaccess faults) instead of dying.\n\nThis change is purely low-level architecture fault/exception handling. It does not introduce any new memory allocations, does not modify data structure fields or padding, does not alter buffer bounds or initialization logic, and does not copy uninitialized kernel memory to userspace. Consequently, there are no uninitialized memory usage or info-leak risks that would require KMSAN fuzzing.",
"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: For your convenience, here is the diff of the changes:
commit fda78ef7dc0f847f7efa4a952132a2986e23e431
Author: syz-cluster <triage@syzkaller.com>
Date: Thu Aug 27 23:24:04 2026 +0000
syz-cluster: applied patch under review
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 0b52557652be6..ca396b4bdda03 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -878,6 +878,9 @@ static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)
return 0;
}
+ if (!user_mode(regs) && fixup_exception(regs, esr))
+ return 0;
+
if (esr & ESR_ELx_FnV) {
siaddr = 0;
} else {
|
| 23/3 | 2026/08/27 23:25 | llm | kmsan-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 2071 output: 34 thoughts: 41 Thoughts: **Analyzing the Arm64 Fault Handling in `fault.c`** Okay, let's dive into this patch. I need to understand the implications, so I'm going straight to the core of the matter: `arch/arm64/mm/fault.c`. The fault handling code is critical, so a change here always warrants careful scrutiny. My initial focus is going to be on `do_sea` and `fixup_exception`. These are the likely entry points for any fault-related processing, and understanding their interaction is key. I'll need to trace the paths through them, see how they interact, and identify exactly what's being modified by this patch. I expect to see detailed checks for the fault type and address, and a conditional sequence based on the system state and the fault's nature. Understanding how this change impacts the existing exception handling logic will be critical to determine whether it is correct and what the performance and/or security impacts of the proposed changes might be. |
| 24/3 | 2026/08/27 23:25 | tool | grepper |
0mArgs:{
"Expression": "do_sea",
"PathPrefix": "arch/arm64/mm/fault.c"
}Results: {
"Output": "arch/arm64/mm/fault.c=861=static int do_bad(unsigned long far, unsigned long esr, struct pt_regs *regs)\n--\narch/arm64/mm/fault.c-865-\narch/arm64/mm/fault.c:866:static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)\narch/arm64/mm/fault.c-867-{\n--\narch/arm64/mm/fault.c=916=static const struct fault_info fault_info[] = {\n--\narch/arm64/mm/fault.c-932-\t{ do_page_fault,\tSIGSEGV, SEGV_ACCERR,\t\"level 3 permission fault\"\t},\narch/arm64/mm/fault.c:933:\t{ do_sea,\t\tSIGBUS, BUS_OBJERR,\t\"synchronous external abort\"\t},\narch/arm64/mm/fault.c-934-\t{ do_tag_check_fault,\tSIGSEGV, SEGV_MTESERR,\t\"synchronous tag check fault\"\t},\narch/arm64/mm/fault.c-935-\t{ do_bad,\t\tSIGKILL, SI_KERNEL,\t\"unknown 18\"\t\t\t},\narch/arm64/mm/fault.c:936:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level -1 (translation table walk)\"\t},\narch/arm64/mm/fault.c:937:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 0 (translation table walk)\"\t},\narch/arm64/mm/fault.c:938:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 1 (translation table walk)\"\t},\narch/arm64/mm/fault.c:939:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 2 (translation table walk)\"\t},\narch/arm64/mm/fault.c:940:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 3 (translation table walk)\"\t},\narch/arm64/mm/fault.c:941:\t{ do_sea,\t\tSIGBUS, BUS_OBJERR,\t\"synchronous parity or ECC error\" },\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c-942-\t{ do_bad,\t\tSIGKILL, SI_KERNEL,\t\"unknown 25\"\t\t\t},\narch/arm64/mm/fault.c-943-\t{ do_bad,\t\tSIGKILL, SI_KERNEL,\t\"unknown 26\"\t\t\t},\narch/arm64/mm/fault.c:944:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level -1 synchronous parity error (translation table walk)\"\t},\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c:945:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 0 synchronous parity error (translation table walk)\"\t},\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c:946:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 1 synchronous parity error (translation table walk)\"\t},\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c:947:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 2 synchronous parity error (translation table walk)\"\t},\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c:948:\t{ do_sea,\t\tSIGKILL, SI_KERNEL,\t\"level 3 synchronous parity error (translation table walk)\"\t},\t// Reserved when RAS is implemented\narch/arm64/mm/fault.c-949-\t{ do_bad,\t\tSIGKILL, SI_KERNEL,\t\"unknown 32\"\t\t\t},\n"
} |
| 25/3 | 2026/08/27 23:25 | llm | kmsan-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 3340 output: 39 thoughts: 24 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Diving into the Arm64 Fault Handler** Alright, let's crack open `arch/arm64/mm/fault.c` and zero in around line 866. Specifically, I need to refresh my memory on how the architecture handles memory faults. I'm especially interested in understanding the nuances of the fault handler and how it differentiates between different fault scenarios and privilege levels. I want to see how the kernel figures out if we are dealing with a page fault, a data abort, instruction abort, or something else entirely. I'm keen on tracing the decision process; how does the code determine the cause of the access violation, and then, how does it react? I'm particularly interested in looking at the way the MMU is interrogated to try to deduce the cause of the problem. |
| 26/3 | 2026/08/27 23:26 | tool | read-file |
0mArgs:{
"File": "arch/arm64/mm/fault.c",
"FirstLine": 860,
"LineCount": 55
}Results: {
"Contents": " 860:\t\n 861:\tstatic int do_bad(unsigned long far, unsigned long esr, struct pt_regs *regs)\n 862:\t{\n 863:\t\treturn 1; /* \"fault\" */\n 864:\t}\n 865:\t\n 866:\tstatic int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)\n 867:\t{\n 868:\t\tconst struct fault_info *inf;\n 869:\t\tunsigned long siaddr;\n 870:\t\n 871:\t\tinf = esr_to_fault_info(esr);\n 872:\t\n 873:\t\tif (user_mode(regs) \u0026\u0026 apei_claim_sea(regs) == 0) {\n 874:\t\t\t/*\n 875:\t\t\t * APEI claimed this as a firmware-first notification.\n 876:\t\t\t * Some processing deferred to task_work before ret_to_user().\n 877:\t\t\t */\n 878:\t\t\treturn 0;\n 879:\t\t}\n 880:\t\n 881:\t\tif (!user_mode(regs) \u0026\u0026 fixup_exception(regs, esr))\n 882:\t\t\treturn 0;\n 883:\t\n 884:\t\tif (esr \u0026 ESR_ELx_FnV) {\n 885:\t\t\tsiaddr = 0;\n 886:\t\t} else {\n 887:\t\t\t/*\n 888:\t\t\t * The architecture specifies that the tag bits of FAR_EL1 are\n 889:\t\t\t * UNKNOWN for synchronous external aborts. Mask them out now\n 890:\t\t\t * so that userspace doesn't see them.\n 891:\t\t\t */\n 892:\t\t\tsiaddr = untagged_addr(far);\n 893:\t\t}\n 894:\t\tadd_taint(TAINT_MACHINE_CHECK, LOCKDEP_STILL_OK);\n 895:\t\tarm64_notify_die(inf-\u003ename, regs, inf-\u003esig, inf-\u003ecode, siaddr, esr);\n 896:\t\n 897:\t\treturn 0;\n 898:\t}\n 899:\t\n 900:\tstatic int do_tag_check_fault(unsigned long far, unsigned long esr,\n 901:\t\t\t\t struct pt_regs *regs)\n 902:\t{\n 903:\t\t/*\n 904:\t\t * The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN\n 905:\t\t * for tag check faults. Set them to corresponding bits in the untagged\n 906:\t\t * address if ARM64_MTE_FAR isn't supported.\n 907:\t\t * Otherwise, bits 63:60 of FAR_EL1 are not UNKNOWN.\n 908:\t\t */\n 909:\t\tif (!cpus_have_cap(ARM64_MTE_FAR))\n 910:\t\t\tfar = (__untagged_addr(far) \u0026 ~MTE_TAG_MASK) | (far \u0026 MTE_TAG_MASK);\n 911:\t\n 912:\t\tdo_bad_area(far, esr, regs);\n 913:\t\treturn 0;\n 914:\t}\n"
} |
| 27/3 | 2026/08/27 23:26 | llm | kmsan-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 4451 output: 30 thoughts: 96 Thoughts: **Analyzing this Patch: A Quick Dive into Exception Handling** Okay, let's get right into this patch. I need to understand the implications of this change, particularly within the context of `do_sea`, the synchronous external abort handler on arm64. I'm seeing it adds a crucial check: ```c if (!user_mode(regs) && fixup_exception(regs, esr)) return 0; ``` My initial thought is to figure out what `fixup_exception` is actually *doing*. Based on the context, I'm pretty sure that it's handling some sort of exception fix-up mechanism. Where's it defined? I'll quickly look it up, likely in `arch/arm64/mm/extable.c` or a related file. I'm guessing this function is central to resolving or masking some sort of exception, and I need to understand the conditions under which it's invoked and what it returns. This could involve an exception table lookup, perhaps some register manipulation, and a possible return to normal execution. I'll need to know whether its handling affects userspace or the kernel. |
| 28/3 | 2026/08/27 23:26 | tool | grepper |
0mArgs:{
"Expression": "fixup_exception",
"PathPrefix": "arch/arm64/"
}Results: {
"Output": "arch/arm64/include/asm/efi.h=16=extern void efi_init(void);\narch/arm64/include/asm/efi.h-17-\narch/arm64/include/asm/efi.h:18:bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg);\narch/arm64/include/asm/efi.h-19-#else\n--\narch/arm64/include/asm/efi.h=22=static inline\narch/arm64/include/asm/efi.h:23:bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)\narch/arm64/include/asm/efi.h-24-{\n--\narch/arm64/include/asm/extable.h=43=bool ex_handler_bpf(const struct exception_table_entry *ex,\n--\narch/arm64/include/asm/extable.h-49-\narch/arm64/include/asm/extable.h:50:bool fixup_exception(struct pt_regs *regs, unsigned long esr);\narch/arm64/include/asm/extable.h-51-#endif\n--\narch/arm64/kernel/efi.c=220=asmlinkage efi_status_t __efi_rt_asm_recover(void);\narch/arm64/kernel/efi.c-221-\narch/arm64/kernel/efi.c:222:bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)\narch/arm64/kernel/efi.c-223-{\n--\narch/arm64/kernel/probes/kprobes.c=301=int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr)\n--\narch/arm64/kernel/probes/kprobes.c-310-\t * must be left alone for the normal page fault handler, including\narch/arm64/kernel/probes/kprobes.c:311:\t * fixup_exception.\narch/arm64/kernel/probes/kprobes.c-312-\t */\n--\narch/arm64/kernel/traps.c=495=void do_el1_bti(struct pt_regs *regs, unsigned long esr)\narch/arm64/kernel/traps.c-496-{\narch/arm64/kernel/traps.c:497:\tif (efi_runtime_fixup_exception(regs, \"BTI violation\")) {\narch/arm64/kernel/traps.c-498-\t\tregs-\u003epstate \u0026= ~PSR_BTYPE_MASK;\n--\narch/arm64/mm/extable.c=69=ex_handler_load_unaligned_zeropad(const struct exception_table_entry *ex,\n--\narch/arm64/mm/extable.c-94-\narch/arm64/mm/extable.c:95:bool fixup_exception(struct pt_regs *regs, unsigned long esr)\narch/arm64/mm/extable.c-96-{\n--\narch/arm64/mm/fault.c=405=static void __do_kernel_fault(unsigned long addr, unsigned long esr,\n--\narch/arm64/mm/fault.c-413-\t */\narch/arm64/mm/fault.c:414:\tif (!is_el1_instruction_abort(esr) \u0026\u0026 fixup_exception(regs, esr))\narch/arm64/mm/fault.c-415-\t\treturn;\n--\narch/arm64/mm/fault.c-450-\narch/arm64/mm/fault.c:451:\tif (efi_runtime_fixup_exception(regs, msg))\narch/arm64/mm/fault.c-452-\t\treturn;\n--\narch/arm64/mm/fault.c=866=static int do_sea(unsigned long far, unsigned long esr, struct pt_regs *regs)\n--\narch/arm64/mm/fault.c-880-\narch/arm64/mm/fault.c:881:\tif (!user_mode(regs) \u0026\u0026 fixup_exception(regs, esr))\narch/arm64/mm/fault.c-882-\t\treturn 0;\n"
} |
| 29/3 | 2026/08/27 23:26 | llm | kmsan-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 5947 output: 39 thoughts: 27 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience and written in the first person: **Diving into `fixup_exception` in `extable.c`** Alright, let's get down to brass tacks. I need to understand what `fixup_exception` is actually doing within `arch/arm64/mm/extable.c`. I'm already pretty familiar with the exception table mechanisms in the kernel, especially on ARM64, but I want to refresh my understanding of *this* specific function. I'm probably looking for how it handles exceptions that arise within exception tables - essentially, the exception to the exception handling, if you will. I'm expecting to see how the code determines if an exception can be recovered from, and if so, how it jumps to the appropriate fixup handler. I'm keen to spot any edge cases or potential race conditions, especially considering the interactions with concurrent processes and interrupts, since we are talking about exception handling at such a low level. Are there any unusual memory access patterns or instruction ordering that are worth noting? I hope to refresh my understanding of this function's logic and the implications of its code, so I can ensure the code that uses this function is optimized and does not cause unexpected issues. |
| 30/3 | 2026/08/27 23:26 | tool | read-file |
0mArgs:{
"File": "arch/arm64/mm/extable.c",
"FirstLine": 90,
"LineCount": 25
}Results: {
"Contents": " 90:\t\n 91:\t\tregs-\u003epc = get_ex_fixup(ex);\n 92:\t\treturn true;\n 93:\t}\n 94:\t\n 95:\tbool fixup_exception(struct pt_regs *regs, unsigned long esr)\n 96:\t{\n 97:\t\tconst struct exception_table_entry *ex;\n 98:\t\n 99:\t\tex = search_exception_tables(instruction_pointer(regs));\n 100:\t\tif (!ex)\n 101:\t\t\treturn false;\n 102:\t\n 103:\t\tswitch (ex-\u003etype) {\n 104:\t\tcase EX_TYPE_BPF:\n 105:\t\t\treturn ex_handler_bpf(ex, regs);\n 106:\t\tcase EX_TYPE_UACCESS_ERR_ZERO:\n 107:\t\tcase EX_TYPE_KACCESS_ERR_ZERO:\n 108:\t\t\treturn ex_handler_uaccess_err_zero(ex, regs);\n 109:\t\tcase EX_TYPE_UACCESS_CPY:\n 110:\t\t\treturn ex_handler_uaccess_cpy(ex, regs, esr);\n 111:\t\tcase EX_TYPE_LOAD_UNALIGNED_ZEROPAD:\n 112:\t\t\treturn ex_handler_load_unaligned_zeropad(ex, regs);\n 113:\t\t}\n 114:\t\n"
} |
| 31/3 | 2026/08/27 23:26 | llm | kmsan-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 6658 output: 179 thoughts: 834 Thoughts: **KMSAN Applicability Assessment for Synchronous External Abort Fix** Okay, let's break down this patch and see if KMSAN is relevant here. First, the core of the patch is about handling Synchronous External Aborts (SEAs) on EL1, specifically in `arch/arm64/mm/fault.c`. When an SEA happens (like during kernel or uaccess memory access, think `copy_from_user` or the like), the `do_sea` function now checks if the fault occurred in kernel mode. If so, it calls `fixup_exception` to see if there's an exception handler available. If a handler exists (we're talking about handlers for things like uaccess, BPF, or `get_user` scenarios), `fixup_exception` does its job: it fixes the registers (zeroing the destination, setting an error return, and adjusting the program counter to the fixup address). This allows the kernel to gracefully handle the fault (like returning `-EFAULT`) instead of immediately panicking via `arm64_notify_die`. Now, the crucial question: does this introduce any KMSAN concerns about uninitialized memory? Let's go through the checklist. 1. **Kernel data structures sent to user space:** Nope. This patch isn't modifying or introducing any new kernel structures that are then passed to userspace via `copy_to_user`, `put_user`, `netlink`, `ioctl`, or anything similar. No risk of leaking uninitialized fields. 2. **Conditional logic based on uninitialized variables:** Nope. The variables involved in `do_sea` (`regs` and `esr`) are parameters provided by low-level exception entry. They are not uninitialized. 3. **Complex data structure allocations:** Nope. There are no allocations involved in this patch at all. 4. **Bounds checks or logic exposing uninitialized bytes:** Nope. This isn't manipulating buffers or altering how bounds checks are performed in a way that would introduce the potential for uninitialized memory reads. 5. **Exception fixup:** Specifically, standard fixup routines zero out the remaining destination buffer or set the error register. KMSAN also doesn't support arm64 in older kernels or runs on x86_64, but even conceptually, exception table fixup for synchronous external aborts is an architecture exception handling / fault recovery mechanism. It does not introduce uninitialized memory leaks or reads of uninitialized memory. So, let's double-check again. What was this *actually* fixing? It's fixing a situation where an SEA during EL1 uaccess or memory access was causing a kernel panic, when instead it should be taking the exception table fixup path (which will return `-EFAULT`). KASAN, LOCKDEP, other detectors vs. KMSAN: This is low-level ARM64 exception handling logic. No new data structures, no memory allocations, no buffer handling, no information leaks to userspace. KMSAN is just not applicable here. `NeedsKMSAN` should be false. My reasoning, structured clearly, is this: * **Patch Summary:** The patch updates `arch/arm64/mm/fault.c` to invoke `fixup_exception()` in `do_sea()` when an EL1 SEA occurs. This enables kernel exception fixup handlers (particularly for uaccess) to handle the fault, avoiding a kernel panic. * **KMSAN Contrast:** KMSAN is for detecting uses and leaks of uninitialized memory. This patch *doesn't* introduce new stack or heap allocations, alter buffer initialization, or create paths that read uninitialized memory. The change only affects exception routing for SEAs on ARM64. Therefore, no uninitialized memory access risk, no kernel-to-user information leaks, and no need for a KMSAN fuzzing session. Alright, that's my assessment. Let's call `set-results`. |
| 32/3 | 2026/08/27 23:26 | tool | set-results |
0mArgs:{
"KMSANReasoning": "The patch modifies `do_sea()` in `arch/arm64/mm/fault.c` to attempt exception fixup via `fixup_exception()` when a Synchronous External Abort (SEA) occurs in kernel mode (`!user_mode(regs)`), allowing graceful recovery (e.g., returning -EFAULT for uaccess faults) instead of dying.\n\nThis change is purely low-level architecture fault/exception handling. It does not introduce any new memory allocations, does not modify data structure fields or padding, does not alter buffer bounds or initialization logic, and does not copy uninitialized kernel memory to userspace. Consequently, there are no uninitialized memory usage or info-leak risks that would require KMSAN fuzzing.",
"NeedsKMSAN": false
}Results: {
"KMSANReasoning": "The patch modifies `do_sea()` in `arch/arm64/mm/fault.c` to attempt exception fixup via `fixup_exception()` when a Synchronous External Abort (SEA) occurs in kernel mode (`!user_mode(regs)`), allowing graceful recovery (e.g., returning -EFAULT for uaccess faults) instead of dying.\n\nThis change is purely low-level architecture fault/exception handling. It does not introduce any new memory allocations, does not modify data structure fields or padding, does not alter buffer bounds or initialization logic, and does not copy uninitialized kernel memory to userspace. Consequently, there are no uninitialized memory usage or info-leak risks that would require KMSAN fuzzing.",
"NeedsKMSAN": false
} |
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