| Seq | Timestamp | Type | Name | Duration |
|---|---|---|---|---|
| 0/0 | 2026/08/12 06:09 | flow | patch-triage |
2mArgs:null Results: {
"EnableConfigs": [
"MEM_ALLOC_PROFILING"
],
"FocusSymbols": [
"sys_init_module",
"sys_finit_module"
],
"KMSANReasoning": "The patch modifies module loading to handle the case where memory allocation profiling tags exceed the available page flag bits. It introduces a retry mechanism in `layout_and_allocate()` by returning `-EAGAIN` from `move_module()` (via `reserve_module_tags()`). The state is saved in a local stack array `frob_size` which is fully initialized using the `for_each_mod_mem_type` macro (iterating over all valid module memory types). The patch also moves `release_module_tags()` earlier in the file to be called during the error path. There are no new structures copied to user space, no complex uninitialized data structures, and no changes to bounds checking that could expose uninitialized memory. Any potential bugs introduced would be logic errors or memory leaks, which are adequately covered by standard KASAN and other bug detectors.",
"NeedsKMSAN": false,
"Reasoning": "The patch modifies the module loading logic to handle a case where memory allocation profiling tags cannot fit in page flag bits. It adds a retry loop in `layout_and_allocate` when `move_module` returns `-EAGAIN`. This is a functional change in the core module loader that is reachable via `init_module` and `finit_module` syscalls when `CONFIG_MEM_ALLOC_PROFILING` is enabled.",
"WorthFuzzing": true
} |
| 1/1 | 2026/08/12 06:09 | action | read-patch-diff |
0mArgs:null Results: {
"PatchDiff": "commit 9f2048479c5c5ae184cf4b18c328c88f02748f5d\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Wed Aug 12 06:09:56 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/kernel/module/main.c b/kernel/module/main.c\nindex 46dd8d25a6058..ed26f167be84d 100644\n--- a/kernel/module/main.c\n+++ b/kernel/module/main.c\n@@ -2944,6 +2944,7 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)\n {\n \tstruct module *mod;\n \tint err;\n+\tunsigned long frob_size[MOD_MEM_NUM_TYPES];\n \n \t/* Allow arches to frob section contents and sizes. */\n \terr = module_frob_arch_sections(info-\u003ehdr, info-\u003esechdrs,\n@@ -2966,18 +2967,38 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)\n \t */\n \tmodule_mark_ro_after_init(info-\u003ehdr, info-\u003esechdrs, info-\u003esecstrings);\n \n+\t/*\n+\t * Save the sizes reserved by module_frob_arch_sections() so they can\n+\t * be restored if we retry below.\n+\t */\n+\tfor_each_mod_mem_type(type)\n+\t\tfrob_size[type] = info-\u003emod-\u003emem[type].size;\n+\n \t/*\n \t * Determine total sizes, and put offsets in sh_entsize. For now\n \t * this is done generically; there doesn't appear to be any\n \t * special cases for the architectures.\n \t */\n+retry:\n \tlayout_sections(info-\u003emod, info);\n \tlayout_symtab(info-\u003emod, info);\n \n \t/* Allocate and move to the final place */\n \terr = move_module(info-\u003emod, info);\n-\tif (err)\n-\t\treturn ERR_PTR(err);\n+\tif (err) {\n+\t\tif (err != -EAGAIN)\n+\t\t\treturn ERR_PTR(err);\n+\t\t/*\n+\t\t * -EAGAIN means profiling was disabled but the module\n+\t\t * can still load without it. Reset state and retry.\n+\t\t */\n+\t\trewrite_section_headers(info, flags);\n+\t\tfor_each_mod_mem_type(type)\n+\t\t\tinfo-\u003emod-\u003emem[type].size = frob_size[type];\n+\t\tinfo-\u003esechdrs[info-\u003eindex.sym].sh_flags \u0026= ~(unsigned long)SHF_ALLOC;\n+\t\tinfo-\u003esechdrs[info-\u003eindex.str].sh_flags \u0026= ~(unsigned long)SHF_ALLOC;\n+\t\tgoto retry;\n+\t}\n \n \t/* Module has been copied to its final place now: return it. */\n \tmod = (void *)info-\u003esechdrs[info-\u003eindex.mod].sh_addr;\ndiff --git a/mm/alloc_tag.c b/mm/alloc_tag.c\nindex b334103104779..112a014d4b890 100644\n--- a/mm/alloc_tag.c\n+++ b/mm/alloc_tag.c\n@@ -835,6 +835,52 @@ static int vm_module_tags_populate(void)\n \treturn 0;\n }\n \n+static void release_module_tags(struct module *mod, bool used)\n+{\n+\tMA_STATE(mas, \u0026mod_area_mt, module_tags.size, module_tags.size);\n+\tstruct alloc_tag *start_tag;\n+\tstruct alloc_tag *end_tag;\n+\tstruct module *val;\n+\n+\tmas_lock(\u0026mas);\n+\tmas_for_each_rev(\u0026mas, val, 0)\n+\t\tif (val == mod)\n+\t\t\tbreak;\n+\n+\tif (!val) /* module not found */\n+\t\tgoto out;\n+\n+\tif (!used)\n+\t\tgoto release_area;\n+\n+\tstart_tag = (struct alloc_tag *)(module_tags.start_addr + mas.index);\n+\tend_tag = (struct alloc_tag *)(module_tags.start_addr + mas.last);\n+\tif (!clean_unused_counters(start_tag, end_tag)) {\n+\t\tstruct alloc_tag *tag;\n+\n+\t\tfor (tag = start_tag; tag \u003c= end_tag; tag++) {\n+\t\t\tstruct alloc_tag_counters counter;\n+\n+\t\t\tif (!tag-\u003ecounters)\n+\t\t\t\tcontinue;\n+\n+\t\t\tcounter = alloc_tag_read(tag);\n+\t\t\tpr_info(\"%s:%u module %s func:%s has %llu allocated at module unload\\n\",\n+\t\t\t\ttag-\u003ect.filename, tag-\u003ect.lineno, tag-\u003ect.modname,\n+\t\t\t\ttag-\u003ect.function, counter.bytes);\n+\t\t}\n+\t} else {\n+\t\tused = false;\n+\t}\n+release_area:\n+\tmas_store(\u0026mas, used ? \u0026unloaded_mod : NULL);\n+\tval = mas_prev_range(\u0026mas, 0);\n+\tif (val == \u0026prepend_mod)\n+\t\tmas_store(\u0026mas, NULL);\n+out:\n+\tmas_unlock(\u0026mas);\n+}\n+\n static void *reserve_module_tags(struct module *mod, unsigned long size,\n \t\t\t\t unsigned int prepend, unsigned long align)\n {\n@@ -904,10 +950,12 @@ static void *reserve_module_tags(struct module *mod, unsigned long size,\n \t\tint grow_res;\n \n \t\tmodule_tags.size = offset + size;\n-\t\tif (mem_alloc_profiling_enabled() \u0026\u0026 !tags_addressable()) {\n+\t\tif (!tags_addressable()) {\n \t\t\tshutdown_mem_profiling(true);\n-\t\t\tpr_warn(\"With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\\n\",\n-\t\t\t\tmod-\u003ename, NR_UNUSED_PAGEFLAG_BITS);\n+\t\t\tpr_warn_once(\"With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\\n\",\n+\t\t\t\t mod-\u003ename, NR_UNUSED_PAGEFLAG_BITS);\n+\t\t\trelease_module_tags(mod, false);\n+\t\t\treturn ERR_PTR(-EAGAIN);\n \t\t}\n \n \t\tgrow_res = vm_module_tags_populate();\n@@ -922,52 +970,6 @@ static void *reserve_module_tags(struct module *mod, unsigned long size,\n \treturn (struct alloc_tag *)(module_tags.start_addr + offset);\n }\n \n-static void release_module_tags(struct module *mod, bool used)\n-{\n-\tMA_STATE(mas, \u0026mod_area_mt, module_tags.size, module_tags.size);\n-\tstruct alloc_tag *start_tag;\n-\tstruct alloc_tag *end_tag;\n-\tstruct module *val;\n-\n-\tmas_lock(\u0026mas);\n-\tmas_for_each_rev(\u0026mas, val, 0)\n-\t\tif (val == mod)\n-\t\t\tbreak;\n-\n-\tif (!val) /* module not found */\n-\t\tgoto out;\n-\n-\tif (!used)\n-\t\tgoto release_area;\n-\n-\tstart_tag = (struct alloc_tag *)(module_tags.start_addr + mas.index);\n-\tend_tag = (struct alloc_tag *)(module_tags.start_addr + mas.last);\n-\tif (!clean_unused_counters(start_tag, end_tag)) {\n-\t\tstruct alloc_tag *tag;\n-\n-\t\tfor (tag = start_tag; tag \u003c= end_tag; tag++) {\n-\t\t\tstruct alloc_tag_counters counter;\n-\n-\t\t\tif (!tag-\u003ecounters)\n-\t\t\t\tcontinue;\n-\n-\t\t\tcounter = alloc_tag_read(tag);\n-\t\t\tpr_info(\"%s:%u module %s func:%s has %llu allocated at module unload\\n\",\n-\t\t\t\ttag-\u003ect.filename, tag-\u003ect.lineno, tag-\u003ect.modname,\n-\t\t\t\ttag-\u003ect.function, counter.bytes);\n-\t\t}\n-\t} else {\n-\t\tused = false;\n-\t}\n-release_area:\n-\tmas_store(\u0026mas, used ? \u0026unloaded_mod : NULL);\n-\tval = mas_prev_range(\u0026mas, 0);\n-\tif (val == \u0026prepend_mod)\n-\t\tmas_store(\u0026mas, NULL);\n-out:\n-\tmas_unlock(\u0026mas);\n-}\n-\n static int load_module(struct module *mod, struct codetag *start, struct codetag *stop)\n {\n \t/* Allocate module alloc_tag percpu counters */\n"
} |
| 2/1 | 2026/08/12 06:09 | agent | patch-evaluator |
1mModel:best-expensive Args: null Results: {
"EnableConfigs": [
"MEM_ALLOC_PROFILING"
],
"FocusSymbols": [
"sys_init_module",
"sys_finit_module"
],
"Reasoning": "The patch modifies the module loading logic to handle a case where memory allocation profiling tags cannot fit in page flag bits. It adds a retry loop in `layout_and_allocate` when `move_module` returns `-EAGAIN`. This is a functional change in the core module loader that is reachable via `init_module` and `finit_module` syscalls when `CONFIG_MEM_ALLOC_PROFILING` is enabled.",
"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 9f2048479c5c5ae184cf4b18c328c88f02748f5d
Author: syz-cluster <triage@syzkaller.com>
Date: Wed Aug 12 06:09:56 2026 +0000
syz-cluster: applied patch under review
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 46dd8d25a6058..ed26f167be84d 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2944,6 +2944,7 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
{
struct module *mod;
int err;
+ unsigned long frob_size[MOD_MEM_NUM_TYPES];
/* Allow arches to frob section contents and sizes. */
err = module_frob_arch_sections(info->hdr, info->sechdrs,
@@ -2966,18 +2967,38 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
*/
module_mark_ro_after_init(info->hdr, info->sechdrs, info->secstrings);
+ /*
+ * Save the sizes reserved by module_frob_arch_sections() so they can
+ * be restored if we retry below.
+ */
+ for_each_mod_mem_type(type)
+ frob_size[type] = info->mod->mem[type].size;
+
/*
* Determine total sizes, and put offsets in sh_entsize. For now
* this is done generically; there doesn't appear to be any
* special cases for the architectures.
*/
+retry:
layout_sections(info->mod, info);
layout_symtab(info->mod, info);
/* Allocate and move to the final place */
err = move_module(info->mod, info);
- if (err)
- return ERR_PTR(err);
+ if (err) {
+ if (err != -EAGAIN)
+ return ERR_PTR(err);
+ /*
+ * -EAGAIN means profiling was disabled but the module
+ * can still load without it. Reset state and retry.
+ */
+ rewrite_section_headers(info, flags);
+ for_each_mod_mem_type(type)
+ info->mod->mem[type].size = frob_size[type];
+ info->sechdrs[info->index.sym].sh_flags &= ~(unsigned long)SHF_ALLOC;
+ info->sechdrs[info->index.str].sh_flags &= ~(unsigned long)SHF_ALLOC;
+ goto retry;
+ }
/* Module has been copied to its final place now: return it. */
mod = (void *)info->sechdrs[info->index.mod].sh_addr;
diff --git a/mm/alloc_tag.c b/mm/alloc_tag.c
index b334103104779..112a014d4b890 100644
--- a/mm/alloc_tag.c
+++ b/mm/alloc_tag.c
@@ -835,6 +835,52 @@ static int vm_module_tags_populate(void)
return 0;
}
+static void release_module_tags(struct module *mod, bool used)
+{
+ MA_STATE(mas, &mod_area_mt, module_tags.size, module_tags.size);
+ struct alloc_tag *start_tag;
+ struct alloc_tag *end_tag;
+ struct module *val;
+
+ mas_lock(&mas);
+ mas_for_each_rev(&mas, val, 0)
+ if (val == mod)
+ break;
+
+ if (!val) /* module not found */
+ goto out;
+
+ if (!used)
+ goto release_area;
+
+ start_tag = (struct alloc_tag *)(module_tags.start_addr + mas.index);
+ end_tag = (struct alloc_tag *)(module_tags.start_addr + mas.last);
+ if (!clean_unused_counters(start_tag, end_tag)) {
+ struct alloc_tag *tag;
+
+ for (tag = start_tag; tag <= end_tag; tag++) {
+ struct alloc_tag_counters counter;
+
+ if (!tag->counters)
+ continue;
+
+ counter = alloc_tag_read(tag);
+ pr_info("%s:%u module %s func:%s has %llu allocated at module unload\n",
+ tag->ct.filename, tag->ct.lineno, tag->ct.modname,
+ tag->ct.function, counter.bytes);
+ }
+ } else {
+ used = false;
+ }
+release_area:
+ mas_store(&mas, used ? &unloaded_mod : NULL);
+ val = mas_prev_range(&mas, 0);
+ if (val == &prepend_mod)
+ mas_store(&mas, NULL);
+out:
+ mas_unlock(&mas);
+}
+
static void *reserve_module_tags(struct module *mod, unsigned long size,
unsigned int prepend, unsigned long align)
{
@@ -904,10 +950,12 @@ static void *reserve_module_tags(struct module *mod, unsigned long size,
int grow_res;
module_tags.size = offset + size;
- if (mem_alloc_profiling_enabled() && !tags_addressable()) {
+ if (!tags_addressable()) {
shutdown_mem_profiling(true);
- pr_warn("With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\n",
- mod->name, NR_UNUSED_PAGEFLAG_BITS);
+ pr_warn_once("With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\n",
+ mod->name, NR_UNUSED_PAGEFLAG_BITS);
+ release_module_tags(mod, false);
+ return ERR_PTR(-EAGAIN);
}
grow_res = vm_module_tags_populate();
@@ -922,52 +970,6 @@ static void *reserve_module_tags(struct module *mod, unsigned long size,
return (struct alloc_tag *)(module_tags.start_addr + offset);
}
-static void release_module_tags(struct module *mod, bool used)
-{
- MA_STATE(mas, &mod_area_mt, module_tags.size, module_tags.size);
- struct alloc_tag *start_tag;
- struct alloc_tag *end_tag;
- struct module *val;
-
- mas_lock(&mas);
- mas_for_each_rev(&mas, val, 0)
- if (val == mod)
- break;
-
- if (!val) /* module not found */
- goto out;
-
- if (!used)
- goto release_area;
-
- start_tag = (struct alloc_tag *)(module_tags.start_addr + mas.index);
- end_tag = (struct alloc_tag *)(module_tags.start_addr + mas.last);
- if (!clean_unused_counters(start_tag, end_tag)) {
- struct alloc_tag *tag;
-
- for (tag = start_tag; tag <= end_tag; tag++) {
- struct alloc_tag_counters counter;
-
- if (!tag->counters)
- continue;
-
- counter = alloc_tag_read(tag);
- pr_info("%s:%u module %s func:%s has %llu allocated at module unload\n",
- tag->ct.filename, tag->ct.lineno, tag->ct.modname,
- tag->ct.function, counter.bytes);
- }
- } else {
- used = false;
- }
-release_area:
- mas_store(&mas, used ? &unloaded_mod : NULL);
- val = mas_prev_range(&mas, 0);
- if (val == &prepend_mod)
- mas_store(&mas, NULL);
-out:
- mas_unlock(&mas);
-}
-
static int load_module(struct module *mod, struct codetag *start, struct codetag *stop)
{
/* Allocate module alloc_tag percpu counters */
|
| 3/2 | 2026/08/12 06:09 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 3927 output: 27 thoughts: 140 Thoughts: **Analyzing a Kernel Module Patch** Okay, so I'm looking at this patch and it seems like it's addressing an `-EAGAIN` error, specifically related to module loading in the kernel. The files being touched are `kernel/module/main.c` and `mm/alloc_tag.c`. The core issue appears to be when `reserve_module_tags` returns `-EAGAIN` – and that happens if we're trying to load a module with memory allocation profiling disabled, but we've somehow hit a limit on the number of tag bits available in page flags. Now, in `kernel/module/main.c`, they've modified `layout_and_allocate` to retry the module load if `move_module` fails with `-EAGAIN`. Hang on a second... `move_module` is the function that actually calls `alloc_module_tags`, isn't it? That seems like a potential connection here. I should probably double-check that by grepping around for those function names. I want to make absolutely sure I'm following the code path correctly and that `move_module` is actually the bottleneck here. Need to verify that relationship explicitly. |
| 4/2 | 2026/08/12 06:10 | tool | grepper |
0mArgs:{
"Expression": "move_module",
"PathPrefix": "kernel/module/"
}Results: {
"Output": "kernel/module/main.c=2364=static int elf_validity_cache_strtab(struct load_info *info)\n--\nkernel/module/main.c-2415- * As a last step we set info-\u003emod to the temporary copy of the module in\nkernel/module/main.c:2416: * info-\u003ehdr. The final one will be allocated in move_module(). Any\nkernel/module/main.c-2417- * modifications we make to our copy of the module will be carried over\n--\nkernel/module/main.c=2659=static int find_module_sections(struct module *mod, struct load_info *info)\n--\nkernel/module/main.c-2787-\nkernel/module/main.c:2788:static int move_module(struct module *mod, struct load_info *info)\nkernel/module/main.c-2789-{\n--\nkernel/module/main.c=2943=static struct module *layout_and_allocate(struct load_info *info, int flags)\n--\nkernel/module/main.c-2986-\t/* Allocate and move to the final place */\nkernel/module/main.c:2987:\terr = move_module(info-\u003emod, info);\nkernel/module/main.c-2988-\tif (err) {\n"
} |
| 5/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 4693 output: 29 thoughts: 10 Thoughts: Okay, let's dive into this code. **Analyzing the Function 'move_module'** Alright, my immediate thought is to understand the purpose and functionality of this `move_module` function. I need to figure out what it's supposed to do. Is it responsible for relocating a module within a larger system, perhaps reorganizing dependencies, or is it more related to data transfer or hardware interaction? My initial goal is to understand the scope and intended behavior of this function. I'll need to look at its inputs, outputs, any internal calls it makes to other functions, and its overall logic. My experience tells me that by examining these elements, I can quickly develop a solid mental model of how `move_module` fits into the broader architecture. I need to determine the 'why' behind its existence before I can assess the 'how'. |
| 6/2 | 2026/08/12 06:10 | tool | grepper |
0mError:no matches Args: {
"Expression": "alloc_module_tags",
"PathPrefix": "kernel/module/"
}Results: {
"error": "no matches"
} |
| 7/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 4923 output: 29 thoughts: 28 Thoughts: Okay, here's my summarized thought process, presented as if I were thinking it: **Digging into Kernel Module Tagging** Alright, I need to understand how the kernel's module tagging system works. Where would I start? Well, `kernel/module/main.c` seems like the logical place to look for the core module handling logic. My gut says that something like `alloc_tag` or perhaps a function named something along the lines of `reserve_module_tags` would be involved in, you know, actually *doing* the tagging or managing those reserved identifiers. Let's see what's in that file and start tracing from there. This is likely where the meat of the functionality lies. |
| 8/2 | 2026/08/12 06:10 | tool | grepper |
0mError:no matches Args: {
"Expression": "reserve_module_tags",
"PathPrefix": "kernel/module/"
}Results: {
"error": "no matches"
} |
| 9/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 5145 output: 27 thoughts: 20 Thoughts: Here's my thought process, as requested: **Navigating Kernel Module Initialization** Okay, I need to dig into how module allocation tags are handled. My initial instinct is to look at the `kernel/module/main.c` file, since that's generally where a lot of the core module loading and initialization logic resides. Specifically, I'm going to search for the term `alloc_tag` within that file. This should give me a good starting point to understand how these tags are defined, used, and managed during module lifecycle events. I expect this search will pinpoint the functions or data structures responsible for handling the allocation tagging. From there, I can trace the code to understand the flow and context within the larger module management framework. |
| 10/2 | 2026/08/12 06:10 | tool | grepper |
0mError:no matches Args: {
"Expression": "alloc_tag",
"PathPrefix": "kernel/module/"
}Results: {
"error": "no matches"
} |
| 11/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 5361 output: 37 thoughts: 50 Thoughts: Okay, let's see... **Deconstructing the Module Relocation Process** Hold on a second. I thought `move_module` was the function responsible for calling `module_frob_arch_sections`. But looking at the call graph, it looks like `layout_and_allocate` is actually the one that does that particular job. I need to make sure I have this straight. Let's go back and check. I think I'll find what I'm looking for in `kernel/module/main.c`, specifically in the `move_module` function. I should be able to get a better understanding of the overall module relocation process by going over the code. Time to dive in... |
| 12/2 | 2026/08/12 06:10 | tool | read-file |
0mArgs:{
"File": "kernel/module/main.c",
"FirstLine": 2788,
"LineCount": 100
}Results: {
"Contents": "2788:\tstatic int move_module(struct module *mod, struct load_info *info)\n2789:\t{\n2790:\t\tint i, ret;\n2791:\t\tenum mod_mem_type t = MOD_MEM_NUM_TYPES;\n2792:\t\tbool codetag_section_found = false;\n2793:\t\n2794:\t\tfor_each_mod_mem_type(type) {\n2795:\t\t\tif (!mod-\u003emem[type].size) {\n2796:\t\t\t\tmod-\u003emem[type].base = NULL;\n2797:\t\t\t\tcontinue;\n2798:\t\t\t}\n2799:\t\n2800:\t\t\tret = module_memory_alloc(mod, type);\n2801:\t\t\tif (ret) {\n2802:\t\t\t\tt = type;\n2803:\t\t\t\tgoto out_err;\n2804:\t\t\t}\n2805:\t\t}\n2806:\t\n2807:\t\t/* Transfer each section which specifies SHF_ALLOC */\n2808:\t\tpr_debug(\"Final section addresses for %s:\\n\", mod-\u003ename);\n2809:\t\tfor (i = 0; i \u003c info-\u003ehdr-\u003ee_shnum; i++) {\n2810:\t\t\tvoid *dest;\n2811:\t\t\tElf_Shdr *shdr = \u0026info-\u003esechdrs[i];\n2812:\t\t\tconst char *sname;\n2813:\t\n2814:\t\t\tif (!(shdr-\u003esh_flags \u0026 SHF_ALLOC))\n2815:\t\t\t\tcontinue;\n2816:\t\n2817:\t\t\tsname = info-\u003esecstrings + shdr-\u003esh_name;\n2818:\t\t\t/*\n2819:\t\t\t * Load codetag sections separately as they might still be used\n2820:\t\t\t * after module unload.\n2821:\t\t\t */\n2822:\t\t\tif (codetag_needs_module_section(mod, sname, shdr-\u003esh_size)) {\n2823:\t\t\t\tdest = codetag_alloc_module_section(mod, sname, shdr-\u003esh_size,\n2824:\t\t\t\t\t\tarch_mod_section_prepend(mod, i), shdr-\u003esh_addralign);\n2825:\t\t\t\tif (WARN_ON(!dest)) {\n2826:\t\t\t\t\tret = -EINVAL;\n2827:\t\t\t\t\tgoto out_err;\n2828:\t\t\t\t}\n2829:\t\t\t\tif (IS_ERR(dest)) {\n2830:\t\t\t\t\tret = PTR_ERR(dest);\n2831:\t\t\t\t\tgoto out_err;\n2832:\t\t\t\t}\n2833:\t\t\t\tcodetag_section_found = true;\n2834:\t\t\t} else {\n2835:\t\t\t\tenum mod_mem_type type = shdr-\u003esh_entsize \u003e\u003e SH_ENTSIZE_TYPE_SHIFT;\n2836:\t\t\t\tunsigned long offset = shdr-\u003esh_entsize \u0026 SH_ENTSIZE_OFFSET_MASK;\n2837:\t\n2838:\t\t\t\tdest = mod-\u003emem[type].base + offset;\n2839:\t\t\t}\n2840:\t\n2841:\t\t\tif (shdr-\u003esh_type != SHT_NOBITS) {\n2842:\t\t\t\t/*\n2843:\t\t\t\t * Our ELF checker already validated this, but let's\n2844:\t\t\t\t * be pedantic and make the goal clearer. We actually\n2845:\t\t\t\t * end up copying over all modifications made to the\n2846:\t\t\t\t * userspace copy of the entire struct module.\n2847:\t\t\t\t */\n2848:\t\t\t\tif (i == info-\u003eindex.mod \u0026\u0026\n2849:\t\t\t\t (WARN_ON_ONCE(shdr-\u003esh_size != sizeof(struct module)))) {\n2850:\t\t\t\t\tret = -ENOEXEC;\n2851:\t\t\t\t\tgoto out_err;\n2852:\t\t\t\t}\n2853:\t\t\t\tmemcpy(dest, (void *)shdr-\u003esh_addr, shdr-\u003esh_size);\n2854:\t\t\t}\n2855:\t\t\t/*\n2856:\t\t\t * Update the userspace copy's ELF section address to point to\n2857:\t\t\t * our newly allocated memory as a pure convenience so that\n2858:\t\t\t * users of info can keep taking advantage and using the newly\n2859:\t\t\t * minted official memory area.\n2860:\t\t\t */\n2861:\t\t\tshdr-\u003esh_addr = (unsigned long)dest;\n2862:\t\t\tpr_debug(\"\\t0x%lx 0x%.8lx %s\\n\", (long)shdr-\u003esh_addr,\n2863:\t\t\t\t (long)shdr-\u003esh_size, info-\u003esecstrings + shdr-\u003esh_name);\n2864:\t\t}\n2865:\t\n2866:\t\treturn 0;\n2867:\tout_err:\n2868:\t\tmodule_memory_restore_rox(mod);\n2869:\t\twhile (t--)\n2870:\t\t\tmodule_memory_free(mod, t);\n2871:\t\tif (codetag_section_found)\n2872:\t\t\tcodetag_free_module_sections(mod);\n2873:\t\n2874:\t\treturn ret;\n2875:\t}\n2876:\t\n2877:\tstatic int check_export_symbol_sections(struct module *mod)\n2878:\t{\n2879:\t\tif (mod-\u003enum_syms \u0026\u0026 !mod-\u003eflagstab) {\n2880:\t\t\tpr_err(\"%s: no flags for exported symbols\\n\", mod-\u003ename);\n2881:\t\t\treturn -ENOEXEC;\n2882:\t\t}\n2883:\t#ifdef CONFIG_MODVERSIONS\n2884:\t\tif (mod-\u003enum_syms \u0026\u0026 !mod-\u003ecrcs) {\n2885:\t\t\treturn try_to_force_load(mod,\n2886:\t\t\t\t\t\t \"no versions for exported symbols\");\n2887:\t\t}\n"
} |
| 13/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 7127 output: 28 thoughts: 33 Thoughts: Okay, here's my interpretation of that thought process, tailored for an expert audience, and presented as if it were my own internal monologue: **Investigating `codetag_alloc_module_section`** Right, `codetag_alloc_module_section` has been invoked. Let's dig into that function. My initial thought is to immediately understand its purpose. I'm already formulating hypotheses. This function likely manages the allocation of a specific section within a code tag structure, right? Probably related to memory management within this particular module. I need to quickly establish if it's handling the initial allocation, or is part of a larger allocation scheme for the sections themselves. I'm going to start by confirming the parameters it receives, and then trace its execution path. I'm looking for memory allocation primitives, and maybe some kind of section metadata management. Hopefully, the naming conventions are decent enough to provide some useful hints. It could be something as simple as ensuring there's space for a new module or as intricate as handling shared code sections. |
| 14/2 | 2026/08/12 06:10 | tool | grepper |
0mArgs:{
"Expression": "codetag_alloc_module_section",
"PathPrefix": ""
}Results: {
"Output": "include/linux/codetag.h=92=bool codetag_needs_module_section(struct module *mod, const char *name,\ninclude/linux/codetag.h-93-\t\t\t\t unsigned long size);\ninclude/linux/codetag.h:94:void *codetag_alloc_module_section(struct module *mod, const char *name,\ninclude/linux/codetag.h-95-\t\t\t\t unsigned long size, unsigned int prepend,\n--\ninclude/linux/codetag.h=107=static inline void *\ninclude/linux/codetag.h:108:codetag_alloc_module_section(struct module *mod, const char *name,\ninclude/linux/codetag.h-109-\t\t\t unsigned long size, unsigned int prepend,\n--\nkernel/module/main.c=2788=static int move_module(struct module *mod, struct load_info *info)\n--\nkernel/module/main.c-2822-\t\tif (codetag_needs_module_section(mod, sname, shdr-\u003esh_size)) {\nkernel/module/main.c:2823:\t\t\tdest = codetag_alloc_module_section(mod, sname, shdr-\u003esh_size,\nkernel/module/main.c-2824-\t\t\t\t\tarch_mod_section_prepend(mod, i), shdr-\u003esh_addralign);\n--\nlib/codetag.c=253=bool codetag_needs_module_section(struct module *mod, const char *name,\n--\nlib/codetag.c-280-\nlib/codetag.c:281:void *codetag_alloc_module_section(struct module *mod, const char *name,\nlib/codetag.c-282-\t\t\t\t unsigned long size, unsigned int prepend,\n"
} |
| 15/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 7857 output: 34 thoughts: 23 Thoughts: Here's my take on the thought process, as if it were my own: **Diving into the Codetag Allocation Module** Okay, time to get my hands dirty. I'm going to start by taking a close look at the `codetag_alloc_module_section` function within `lib/codetag.c`. I need to understand exactly how the codetag module is allocating its resources. This section is critical, because proper allocation and management are fundamental to memory safety and performance. I need to figure out the specific allocation strategies used: are we dealing with statically allocated blocks, dynamic allocation with `malloc`, a custom allocator, or something else entirely? I also need to identify any potential race conditions and performance bottlenecks. |
| 16/2 | 2026/08/12 06:10 | tool | read-file |
0mArgs:{
"File": "lib/codetag.c",
"FirstLine": 281,
"LineCount": 50
}Results: {
"Contents": " 281:\tvoid *codetag_alloc_module_section(struct module *mod, const char *name,\n 282:\t\t\t\t\t unsigned long size, unsigned int prepend,\n 283:\t\t\t\t\t unsigned long align)\n 284:\t{\n 285:\t\tconst char *type_name = name + strlen(CODETAG_SECTION_PREFIX);\n 286:\t\tstruct codetag_type *cttype;\n 287:\t\tvoid *ret = ERR_PTR(-EINVAL);\n 288:\t\n 289:\t\tmutex_lock(\u0026codetag_lock);\n 290:\t\tlist_for_each_entry(cttype, \u0026codetag_types, link) {\n 291:\t\t\tif (strcmp(type_name, cttype-\u003edesc.section) == 0) {\n 292:\t\t\t\tif (WARN_ON(!cttype-\u003edesc.alloc_section_mem))\n 293:\t\t\t\t\tbreak;\n 294:\t\n 295:\t\t\t\tdown_write(\u0026cttype-\u003emod_lock);\n 296:\t\t\t\tret = cttype-\u003edesc.alloc_section_mem(mod, size, prepend, align);\n 297:\t\t\t\tup_write(\u0026cttype-\u003emod_lock);\n 298:\t\t\t\tbreak;\n 299:\t\t\t}\n 300:\t\t}\n 301:\t\tmutex_unlock(\u0026codetag_lock);\n 302:\t\n 303:\t\treturn ret;\n 304:\t}\n 305:\t\n 306:\tvoid codetag_free_module_sections(struct module *mod)\n 307:\t{\n 308:\t\tstruct codetag_type *cttype;\n 309:\t\n 310:\t\tmutex_lock(\u0026codetag_lock);\n 311:\t\tlist_for_each_entry(cttype, \u0026codetag_types, link) {\n 312:\t\t\tif (!cttype-\u003edesc.free_section_mem)\n 313:\t\t\t\tcontinue;\n 314:\t\n 315:\t\t\tdown_write(\u0026cttype-\u003emod_lock);\n 316:\t\t\tcttype-\u003edesc.free_section_mem(mod, false);\n 317:\t\t\tup_write(\u0026cttype-\u003emod_lock);\n 318:\t\t}\n 319:\t\tmutex_unlock(\u0026codetag_lock);\n 320:\t}\n 321:\t\n 322:\tvoid codetag_module_replaced(struct module *mod, struct module *new_mod)\n 323:\t{\n 324:\t\tstruct codetag_type *cttype;\n 325:\t\n 326:\t\tmutex_lock(\u0026codetag_lock);\n 327:\t\tlist_for_each_entry(cttype, \u0026codetag_types, link) {\n 328:\t\t\tif (!cttype-\u003edesc.module_replaced)\n 329:\t\t\t\tcontinue;\n 330:\t\n"
} |
| 17/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 8823 output: 25 thoughts: 27 Thoughts: Here's my thought process, as if I were analyzing that code: **Analyzing the Memory Allocation** Okay, so `alloc_section_mem` has been called. That's our starting point. Now, the crucial thing is to understand where and how this `alloc_section_mem` function is actually *defined* or, more precisely, *set*. It's not enough to know it's being called; I need to trace back to its origin. I need to figure out the context in which this allocation is happening. What's driving this call? Where is the memory actually being managed? Is this dynamic allocation? Is it part of a larger memory map? Knowing the location of its setup will unlock a far more comprehensive grasp of the process. I want the breadcrumbs; I want to follow the call stack upstream to figure out the larger picture! |
| 18/2 | 2026/08/12 06:10 | tool | grepper |
0mArgs:{
"Expression": "alloc_section_mem",
"PathPrefix": ""
}Results: {
"Output": "include/linux/codetag.h=39=struct codetag_type_desc {\n--\ninclude/linux/codetag.h-48-\tbool (*needs_section_mem)(struct module *mod, unsigned long size);\ninclude/linux/codetag.h:49:\tvoid *(*alloc_section_mem)(struct module *mod, unsigned long size,\ninclude/linux/codetag.h-50-\t\t\t\t unsigned int prepend, unsigned long align);\n--\nlib/alloc_tag.c=983=static int __init alloc_tag_init(void)\n--\nlib/alloc_tag.c-989-\t\t.needs_section_mem\t= needs_section_mem,\nlib/alloc_tag.c:990:\t\t.alloc_section_mem\t= reserve_module_tags,\nlib/alloc_tag.c-991-\t\t.free_section_mem\t= release_module_tags,\n--\nlib/codetag.c=281=void *codetag_alloc_module_section(struct module *mod, const char *name,\n--\nlib/codetag.c-291-\t\tif (strcmp(type_name, cttype-\u003edesc.section) == 0) {\nlib/codetag.c:292:\t\t\tif (WARN_ON(!cttype-\u003edesc.alloc_section_mem))\nlib/codetag.c-293-\t\t\t\tbreak;\n--\nlib/codetag.c-295-\t\t\tdown_write(\u0026cttype-\u003emod_lock);\nlib/codetag.c:296:\t\t\tret = cttype-\u003edesc.alloc_section_mem(mod, size, prepend, align);\nlib/codetag.c-297-\t\t\tup_write(\u0026cttype-\u003emod_lock);\n--\nmm/alloc_tag.c=1324=static int __init alloc_tag_init(void)\n--\nmm/alloc_tag.c-1330-\t\t.needs_section_mem\t= needs_section_mem,\nmm/alloc_tag.c:1331:\t\t.alloc_section_mem\t= reserve_module_tags,\nmm/alloc_tag.c-1332-\t\t.free_section_mem\t= release_module_tags,\n"
} |
| 19/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 9608 output: 35 thoughts: 91 Thoughts: **Analyzing the Code Modification** Okay, so it looks like the key change I need to understand is related to `reserve_module_tags`. Right, that function name clicks. And the patch is modifying `reserve_module_tags` to return `ERR_PTR(-EAGAIN)` under a specific condition. Let me make sure I understand this - if `!tags_addressable()`, it returns an error. The patch is working within `mm/alloc_tag.c`, which is the correct file. Now let me take a look at the code for the function `reserve_module_tags` to properly assess the effects of the modifications. |
| 20/2 | 2026/08/12 06:10 | tool | read-file |
0mArgs:{
"File": "mm/alloc_tag.c",
"FirstLine": 945,
"LineCount": 50
}Results: {
"Contents": " 945:\t\n 946:\t\tif (IS_ERR(ret))\n 947:\t\t\treturn ret;\n 948:\t\n 949:\t\tif (module_tags.size \u003c offset + size) {\n 950:\t\t\tint grow_res;\n 951:\t\n 952:\t\t\tmodule_tags.size = offset + size;\n 953:\t\t\tif (!tags_addressable()) {\n 954:\t\t\t\tshutdown_mem_profiling(true);\n 955:\t\t\t\tpr_warn_once(\"With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\\n\",\n 956:\t\t\t\t\t mod-\u003ename, NR_UNUSED_PAGEFLAG_BITS);\n 957:\t\t\t\trelease_module_tags(mod, false);\n 958:\t\t\t\treturn ERR_PTR(-EAGAIN);\n 959:\t\t\t}\n 960:\t\n 961:\t\t\tgrow_res = vm_module_tags_populate();\n 962:\t\t\tif (grow_res) {\n 963:\t\t\t\tshutdown_mem_profiling(true);\n 964:\t\t\t\tpr_err(\"Failed to allocate memory for allocation tags in the module %s. Memory allocation profiling is disabled!\\n\",\n 965:\t\t\t\t mod-\u003ename);\n 966:\t\t\t\treturn ERR_PTR(grow_res);\n 967:\t\t\t}\n 968:\t\t}\n 969:\t\n 970:\t\treturn (struct alloc_tag *)(module_tags.start_addr + offset);\n 971:\t}\n 972:\t\n 973:\tstatic int load_module(struct module *mod, struct codetag *start, struct codetag *stop)\n 974:\t{\n 975:\t\t/* Allocate module alloc_tag percpu counters */\n 976:\t\tstruct alloc_tag *start_tag;\n 977:\t\tstruct alloc_tag *stop_tag;\n 978:\t\tstruct alloc_tag *tag;\n 979:\t\n 980:\t\t/* percpu counters for core allocations are already statically allocated */\n 981:\t\tif (!mod)\n 982:\t\t\treturn 0;\n 983:\t\n 984:\t\tstart_tag = ct_to_alloc_tag(start);\n 985:\t\tstop_tag = ct_to_alloc_tag(stop);\n 986:\t\tfor (tag = start_tag; tag \u003c stop_tag; tag++) {\n 987:\t\t\tWARN_ON(tag-\u003ecounters);\n 988:\t\t\ttag-\u003ecounters = alloc_percpu(struct alloc_tag_counters);\n 989:\t\t\tif (!tag-\u003ecounters) {\n 990:\t\t\t\twhile (--tag \u003e= start_tag) {\n 991:\t\t\t\t\tfree_percpu(tag-\u003ecounters);\n 992:\t\t\t\t\ttag-\u003ecounters = NULL;\n 993:\t\t\t\t}\n 994:\t\t\t\tpr_err(\"Failed to allocate memory for allocation tag percpu counters in the module %s\\n\",\n"
} |
| 21/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 10644 output: 29 thoughts: 134 Thoughts: **Module Loading Behavior with Memory Allocation Profiling** Okay, so I'm tracking this change in the module loader. It looks like the system is set up so that if `!tags_addressable()` returns true, memory profiling is disabled and an `-EAGAIN` error is returned. That's a key point. This `-EAGAIN` gets passed back up the call stack, specifically through `move_module`. Then, down in `layout_and_allocate`, the code actively *catches* that `-EAGAIN` error, resets some internal state, and then *retries* the allocation process. That's a pretty significant functional change, isn't it? It essentially introduces a retry mechanism in response to a specific condition. The next question is, "When is this actually hit?" It's reachable if a module is loaded and `!tags_addressable()` is true at any point. Then I remember that `tags_addressable()` itself is checking if the tags associated with memory allocation can fit within the available page flag bits. That implies this is directly related to when memory allocation profiling is enabled. Right, the `CONFIG_MEM_ALLOC_PROFILING` config option. So, this retry behavior is only triggered when memory allocation profiling is active and the tags are too big to fit in the page flags, then it should trigger `-EAGAIN`. |
| 22/2 | 2026/08/12 06:10 | tool | grepper |
0mArgs:{
"Expression": "MEM_ALLOC_PROFILING",
"PathPrefix": "mm/"
}Results: {
"Output": "mm/Kconfig.debug=311=config PER_VMA_LOCK_STATS\n--\nmm/Kconfig.debug-323-\nmm/Kconfig.debug:324:config MEM_ALLOC_PROFILING\nmm/Kconfig.debug-325-\tbool \"Enable memory allocation profiling\"\n--\nmm/Kconfig.debug-337-\nmm/Kconfig.debug:338:config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT\nmm/Kconfig.debug-339-\tbool \"Enable memory allocation profiling by default\"\nmm/Kconfig.debug-340-\tdefault y\nmm/Kconfig.debug:341:\tdepends on MEM_ALLOC_PROFILING\nmm/Kconfig.debug-342-\nmm/Kconfig.debug:343:config MEM_ALLOC_PROFILING_DEBUG\nmm/Kconfig.debug-344-\tbool \"Memory allocation profiler debugging\"\nmm/Kconfig.debug-345-\tdefault n\nmm/Kconfig.debug:346:\tdepends on MEM_ALLOC_PROFILING\nmm/Kconfig.debug:347:\tselect MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT\nmm/Kconfig.debug-348-\thelp\n--\nmm/Makefile=149=obj-$(CONFIG_LAZY_MMU_MODE_KUNIT_TEST) += tests/lazy_mmu_mode_kunit.o\nmm/Makefile:150:obj-$(CONFIG_MEM_ALLOC_PROFILING) += alloc_tag.o\n--\nmm/alloc_tag.c-28-\nmm/alloc_tag.c:29:#ifdef CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT\nmm/alloc_tag.c-30-static bool mem_profiling_support = true;\n--\nmm/alloc_tag.c=48=EXPORT_SYMBOL(_shared_alloc_tag);\n--\nmm/alloc_tag.c-50-\nmm/alloc_tag.c:51:DEFINE_STATIC_KEY_MAYBE(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT,\nmm/alloc_tag.c-52-\t\t\tmem_alloc_profiling_key);\n--\nmm/alloc_tag.c=1116=static __init bool need_page_alloc_tagging(void)\n--\nmm/alloc_tag.c-1123-\nmm/alloc_tag.c:1124:#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG\nmm/alloc_tag.c-1125-/*\n--\nmm/alloc_tag.c=1202=static void __init clear_early_alloc_pfn_tag_refs(void)\n--\nmm/alloc_tag.c-1255-}\nmm/alloc_tag.c:1256:#else /* !CONFIG_MEM_ALLOC_PROFILING_DEBUG */\nmm/alloc_tag.c-1257-static inline void __init clear_early_alloc_pfn_tag_refs(void) {}\nmm/alloc_tag.c:1258:#endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */\nmm/alloc_tag.c-1259-\n--\nmm/alloc_tag.c=1277=static int proc_mem_profiling_handler(const struct ctl_table *table, int write,\n--\nmm/alloc_tag.c-1288-\nmm/alloc_tag.c:1289:#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG\nmm/alloc_tag.c-1290-\t\t/* User can't toggle profiling while debugging */\n--\nmm/page_alloc.c=1220=static void clear_highpages_kasan_tagged(struct page *page, int numpages)\n--\nmm/page_alloc.c-1234-\nmm/page_alloc.c:1235:#ifdef CONFIG_MEM_ALLOC_PROFILING\nmm/page_alloc.c-1236-\n--\nmm/page_alloc.c=1301=static inline void pgalloc_tag_sub_pages(struct alloc_tag *tag, unsigned int nr)\n--\nmm/page_alloc.c-1306-\nmm/page_alloc.c:1307:#else /* CONFIG_MEM_ALLOC_PROFILING */\nmm/page_alloc.c-1308-\n--\nmm/page_alloc.c=1312=static inline void pgalloc_tag_sub_pages(struct alloc_tag *tag, unsigned int nr) {}\nmm/page_alloc.c-1313-\nmm/page_alloc.c:1314:#endif /* CONFIG_MEM_ALLOC_PROFILING */\nmm/page_alloc.c-1315-\n--\nmm/page_ext.c=80=static struct page_ext_operations *page_ext_ops[] __initdata = {\n--\nmm/page_ext.c-86-#endif\nmm/page_ext.c:87:#ifdef CONFIG_MEM_ALLOC_PROFILING\nmm/page_ext.c-88-\t\u0026page_alloc_tagging_ops,\n--\nmm/page_ext.c=100=static unsigned long total_usage;\nmm/page_ext.c-101-\nmm/page_ext.c:102:#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG\nmm/page_ext.c-103-/*\n--\nmm/percpu-internal.h=35=struct pcpuobj_ext {\n--\nmm/percpu-internal.h-38-#endif\nmm/percpu-internal.h:39:#ifdef CONFIG_MEM_ALLOC_PROFILING\nmm/percpu-internal.h-40-\tunion codetag_ref\ttag;\n--\nmm/percpu-internal.h-43-\nmm/percpu-internal.h:44:#if defined(CONFIG_MEMCG) || defined(CONFIG_MEM_ALLOC_PROFILING)\nmm/percpu-internal.h-45-#define NEED_PCPUOBJ_EXT\n--\nmm/percpu-internal.h=90=static inline bool need_pcpuobj_ext(void)\nmm/percpu-internal.h-91-{\nmm/percpu-internal.h:92:\tif (IS_ENABLED(CONFIG_MEM_ALLOC_PROFILING))\nmm/percpu-internal.h-93-\t\treturn true;\n--\nmm/percpu.c=1690=static void pcpu_memcg_free_hook(struct pcpu_chunk *chunk, int off, size_t size)\n--\nmm/percpu.c-1694-\nmm/percpu.c:1695:#ifdef CONFIG_MEM_ALLOC_PROFILING\nmm/percpu.c-1696-static void pcpu_alloc_tag_alloc_hook(struct pcpu_chunk *chunk, int off,\n--\nmm/show_mem.c=408=void __show_mem(unsigned int filter, const nodemask_t *nodemask,\n--\nmm/show_mem.c-434-#endif\nmm/show_mem.c:435:#ifdef CONFIG_MEM_ALLOC_PROFILING\nmm/show_mem.c-436-\tstatic DEFINE_SPINLOCK(mem_alloc_profiling_spinlock);\n--\nmm/slub.c=2046=static inline void dec_slabs_node(struct kmem_cache *s, int node,\n--\nmm/slub.c-2063-\nmm/slub.c:2064:#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG\nmm/slub.c-2065-\n--\nmm/slub.c=2097=static inline void handle_failed_objexts_alloc(unsigned long obj_exts,\n--\nmm/slub.c-2112-\nmm/slub.c:2113:#else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */\nmm/slub.c-2114-\n--\nmm/slub.c=2117=static inline void handle_failed_objexts_alloc(unsigned long obj_exts,\n--\nmm/slub.c-2119-\nmm/slub.c:2120:#endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */\nmm/slub.c-2121-\n--\nmm/slub.c=2314=static inline void alloc_slab_obj_exts_early(struct kmem_cache *s,\n--\nmm/slub.c-2320-\nmm/slub.c:2321:#ifdef CONFIG_MEM_ALLOC_PROFILING\nmm/slub.c-2322-\n--\nmm/slub.c=2409=alloc_tagging_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p,\n--\nmm/slub.c-2415-\nmm/slub.c:2416:#else /* CONFIG_MEM_ALLOC_PROFILING */\nmm/slub.c-2417-\n--\nmm/slub.c=2425=alloc_tagging_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p,\n--\nmm/slub.c-2429-\nmm/slub.c:2430:#endif /* CONFIG_MEM_ALLOC_PROFILING */\nmm/slub.c-2431-\n"
} |
| 23/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 13461 output: 36 thoughts: 116 Thoughts: **Analyzing a Potential Fuzzing Target** Okay, so I've spotted `CONFIG_MEM_ALLOC_PROFILING` in the config – interesting. My initial thought is, is this a functional change, and is it worth the effort to set up fuzzing against it? It looks like it introduces a retry loop within `layout_and_allocate`. The code now retries the allocation process if `move_module` returns `-EAGAIN`. This new handling seems to address a specific edge case where `reserve_module_tags` might fail due to the number of tags exceeding available page flag bits. Let me just quickly refresh my memory, `layout_and_allocate` is located in `kernel/module/main.c`, right? Okay, just want to double-check that this is correct. Time to take a closer look at `layout_and_allocate` again. Need to be certain before I go further. |
| 24/2 | 2026/08/12 06:10 | tool | read-file |
0mArgs:{
"File": "kernel/module/main.c",
"FirstLine": 2944,
"LineCount": 50
}Results: {
"Contents": "2944:\t{\n2945:\t\tstruct module *mod;\n2946:\t\tint err;\n2947:\t\tunsigned long frob_size[MOD_MEM_NUM_TYPES];\n2948:\t\n2949:\t\t/* Allow arches to frob section contents and sizes. */\n2950:\t\terr = module_frob_arch_sections(info-\u003ehdr, info-\u003esechdrs,\n2951:\t\t\t\t\t\tinfo-\u003esecstrings, info-\u003emod);\n2952:\t\tif (err \u003c 0)\n2953:\t\t\treturn ERR_PTR(err);\n2954:\t\n2955:\t\terr = module_enforce_rwx_sections(info-\u003ehdr, info-\u003esechdrs,\n2956:\t\t\t\t\t\t info-\u003esecstrings, info-\u003emod);\n2957:\t\tif (err \u003c 0)\n2958:\t\t\treturn ERR_PTR(err);\n2959:\t\n2960:\t\t/* We will do a special allocation for per-cpu sections later. */\n2961:\t\tinfo-\u003esechdrs[info-\u003eindex.pcpu].sh_flags \u0026= ~(unsigned long)SHF_ALLOC;\n2962:\t\n2963:\t\t/*\n2964:\t\t * Mark relevant sections as SHF_RO_AFTER_INIT so layout_sections() can\n2965:\t\t * put them in the right place.\n2966:\t\t * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set.\n2967:\t\t */\n2968:\t\tmodule_mark_ro_after_init(info-\u003ehdr, info-\u003esechdrs, info-\u003esecstrings);\n2969:\t\n2970:\t\t/*\n2971:\t\t * Save the sizes reserved by module_frob_arch_sections() so they can\n2972:\t\t * be restored if we retry below.\n2973:\t\t */\n2974:\t\tfor_each_mod_mem_type(type)\n2975:\t\t\tfrob_size[type] = info-\u003emod-\u003emem[type].size;\n2976:\t\n2977:\t\t/*\n2978:\t\t * Determine total sizes, and put offsets in sh_entsize. For now\n2979:\t\t * this is done generically; there doesn't appear to be any\n2980:\t\t * special cases for the architectures.\n2981:\t\t */\n2982:\tretry:\n2983:\t\tlayout_sections(info-\u003emod, info);\n2984:\t\tlayout_symtab(info-\u003emod, info);\n2985:\t\n2986:\t\t/* Allocate and move to the final place */\n2987:\t\terr = move_module(info-\u003emod, info);\n2988:\t\tif (err) {\n2989:\t\t\tif (err != -EAGAIN)\n2990:\t\t\t\treturn ERR_PTR(err);\n2991:\t\t\t/*\n2992:\t\t\t * -EAGAIN means profiling was disabled but the module\n2993:\t\t\t * can still load without it. Reset state and retry.\n"
} |
| 25/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 14604 output: 33 thoughts: 351 Thoughts: **Fuzzing the Module Loading Retry Logic** Okay, so I'm looking at this kernel code snippet, specifically the retry logic in module loading, triggered when a `-EAGAIN` error is encountered. My initial thought is, this is definitely worth investigating from a fuzzing perspective. It's touching core module loading logic, and any deviation or unexpected behavior here could have pretty serious implications. The code's purpose is to retry after handling a `-EAGAIN` error, which signifies that profiling was disabled, but the module can still be loaded. It rewrites section headers, adjusts memory sizes for different types, and clears the `SHF_ALLOC` flag for symbol and string table sections, then retries. This reset and retry mechanism screams potential for subtle bugs, especially in a concurrent environment. Given that module loading is reached via `init_module` and `finit_module` syscalls, this is definitely a reachable code path. The `MEM_ALLOC_PROFILING` config option is the key to trigger it. Now, which functions are the key targets here? `layout_and_allocate`, `move_module`, and `reserve_module_tags` are immediately on my radar. A quick check reveals that all three are static functions. While static functions can still be valuable targets, I need to look for any public interfaces that call them, because these are harder to target directly. The `load_module` is static, which is called, I believe, when calling `init_module`. That seems to be the entrypoint. I also should note that the system call to trigger this is `sys_init_module`. |
| 26/2 | 2026/08/12 06:10 | tool | grepper |
0mArgs:{
"Expression": "SYSCALL_DEFINE.*init_module",
"PathPrefix": "kernel/module/"
}Results: {
"Output": "kernel/module/main.c=3443=static int load_module(struct load_info *info, const char __user *uargs,\n--\nkernel/module/main.c-3654-\nkernel/module/main.c:3655:SYSCALL_DEFINE3(init_module, void __user *, umod,\nkernel/module/main.c-3656-\t\tunsigned long, len, const char __user *, uargs)\n--\nkernel/module/main.c=3801=static int idempotent_init_module(struct file *f, const char __user * uargs, int flags)\n--\nkernel/module/main.c-3819-\nkernel/module/main.c:3820:SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)\nkernel/module/main.c-3821-{\n"
} |
| 27/2 | 2026/08/12 06:10 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 15568 output: 28 thoughts: 189 Thoughts: **Analyzing Module Initialization and Allocation** Okay, so I'm diving into this module initialization process. My initial thought is to zero in on `sys_init_module` and `sys_finit_module` – those are the entry points, right? But hold on, the call chain is a bit more intricate. `layout_and_allocate` gets called by `load_module`. And `load_module`, in turn, is triggered by `init_module` and `finit_module`. Now, the question is: which of these functions are modified? The goal is to identify a focus. Are there any non-static functions that I can dig into? Nope, `layout_and_allocate` and `reserve_module_tags` are both static. Hmm, hang on, `reserve_module_tags` is being assigned to a function pointer called `alloc_section_mem` within `alloc_tag_init`. That's something to keep in mind. Let's rethink this. Back to the hunt for something non-static. `load_module` is static. That doesn't help. So, it looks like it will come down to `sys_init_module` and `sys_finit_module`. I'll go check `kernel/module/main.c` to see if there are any other non-static functions of interest. |
| 28/2 | 2026/08/12 06:11 | tool | grepper |
0mArgs:{
"Expression": "^int .*module",
"PathPrefix": "kernel/module/"
}Results: {
"Output": "kernel/module/decompress.c=207=static ssize_t module_zstd_decompress(struct load_info *info,\n--\nkernel/module/decompress.c-293-\nkernel/module/decompress.c:294:int module_decompress(struct load_info *info, const void *buf, size_t size)\nkernel/module/decompress.c-295-{\n--\nkernel/module/internal.h=120=int mod_verify_sig(const void *mod, struct load_info *info);\nkernel/module/internal.h:121:int try_to_force_load(struct module *mod, const char *reason);\nkernel/module/internal.h-122-bool find_symbol(struct find_symbol_arg *fsa);\n--\nkernel/module/internal.h=135=static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym)\n--\nkernel/module/internal.h-144-#ifdef CONFIG_LIVEPATCH\nkernel/module/internal.h:145:int copy_module_elf(struct module *mod, struct load_info *info);\nkernel/module/internal.h-146-void free_module_elf(struct module *mod);\n--\nkernel/module/internal.h=209=struct mod_fail_load {\n--\nkernel/module/internal.h-215-\nkernel/module/internal.h:216:int try_add_failed_module(const char *name, enum fail_dup_mod_reason reason);\nkernel/module/internal.h-217-void mod_stat_bump_invalid(struct load_info *info, int flags);\n--\nkernel/module/internal.h=256=struct mod_unload_taint {\n--\nkernel/module/internal.h-262-\nkernel/module/internal.h:263:int try_add_tainted_module(struct module *mod);\nkernel/module/internal.h-264-void print_unloaded_tainted_modules(void);\n--\nkernel/module/internal.h=271=static inline void print_unloaded_tainted_modules(void)\n--\nkernel/module/internal.h-276-#ifdef CONFIG_MODULE_DECOMPRESS\nkernel/module/internal.h:277:int module_decompress(struct load_info *info, const void *buf, size_t size);\nkernel/module/internal.h-278-void module_decompress_cleanup(struct load_info *info);\n--\nkernel/module/internal.h=315=static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree)\n--\nkernel/module/internal.h-328-\nkernel/module/internal.h:329:int module_enable_rodata_ro(const struct module *mod);\nkernel/module/internal.h:330:int module_enable_rodata_ro_after_init(const struct module *mod);\nkernel/module/internal.h:331:int module_enable_data_nx(const struct module *mod);\nkernel/module/internal.h:332:int module_enable_text_rox(const struct module *mod);\nkernel/module/internal.h:333:int module_enforce_rwx_sections(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,\nkernel/module/internal.h-334-\t\t\t\tconst char *secstrings,\n--\nkernel/module/internal.h=336=void module_mark_ro_after_init(const Elf_Ehdr *hdr, Elf_Shdr *sechdrs,\n--\nkernel/module/internal.h-339-#ifdef CONFIG_MODULE_SIG\nkernel/module/internal.h:340:int module_sig_check(struct load_info *info, int flags);\nkernel/module/internal.h-341-#else /* !CONFIG_MODULE_SIG */\n--\nkernel/module/internal.h=367=static inline void add_kallsyms(struct module *mod, const struct load_info *info) { }\n--\nkernel/module/internal.h-370-#ifdef CONFIG_SYSFS\nkernel/module/internal.h:371:int mod_sysfs_setup(struct module *mod, const struct load_info *info,\nkernel/module/internal.h-372-\t\t struct kernel_param *kparam, unsigned int num_params);\n--\nkernel/module/internal.h=391=void module_layout(struct module *mod, struct modversion_info *ver, struct kernel_param *kp,\nkernel/module/internal.h-392-\t\t struct kernel_symbol *ks, struct tracepoint * const *tp);\nkernel/module/internal.h:393:int check_modstruct_version(const struct load_info *info, struct module *mod);\nkernel/module/internal.h-394-int same_magic(const char *amagic, const char *bmagic, bool has_crcs);\n--\nkernel/module/kallsyms.c=311=void * __weak dereference_module_function_descriptor(struct module *mod,\n--\nkernel/module/kallsyms.c-320- */\nkernel/module/kallsyms.c:321:int module_address_lookup(unsigned long addr,\nkernel/module/kallsyms.c-322-\t\t\t unsigned long *size,\n--\nkernel/module/kallsyms.c-347-\nkernel/module/kallsyms.c:348:int lookup_module_symbol_name(unsigned long addr, char *symname)\nkernel/module/kallsyms.c-349-{\n--\nkernel/module/kallsyms.c-370-\nkernel/module/kallsyms.c:371:int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,\nkernel/module/kallsyms.c-372-\t\t char *name, char *module_name, int *exported)\n--\nkernel/module/kallsyms.c=447=unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name)\n--\nkernel/module/kallsyms.c-452-\nkernel/module/kallsyms.c:453:int module_kallsyms_on_each_symbol(const char *modname,\nkernel/module/kallsyms.c-454-\t\t\t\t int (*fn)(void *, const char *, unsigned long),\n--\nkernel/module/kmod.c=72=static int call_modprobe(char *orig_module_name, int wait)\n--\nkernel/module/kmod.c-131- */\nkernel/module/kmod.c:132:int __request_module(bool wait, const char *fmt, ...)\nkernel/module/kmod.c-133-{\n--\nkernel/module/livepatch.c-17- */\nkernel/module/livepatch.c:18:int copy_module_elf(struct module *mod, struct load_info *info)\nkernel/module/livepatch.c-19-{\n--\nkernel/module/main.c=164=static BLOCKING_NOTIFIER_HEAD(module_notify_list);\nkernel/module/main.c-165-\nkernel/module/main.c:166:int register_module_notifier(struct notifier_block *nb)\nkernel/module/main.c-167-{\n--\nkernel/module/main.c=170=EXPORT_SYMBOL(register_module_notifier);\nkernel/module/main.c-171-\nkernel/module/main.c:172:int unregister_module_notifier(struct notifier_block *nb)\nkernel/module/main.c-173-{\n--\nkernel/module/main.c=772=static int try_stop_module(struct module *mod, int flags, int *forced)\n--\nkernel/module/main.c-794- */\nkernel/module/main.c:795:int module_refcount(struct module *mod)\nkernel/module/main.c-796-{\n--\nkernel/module/main.c=1105=static const char vermagic[] = VERMAGIC_STRING;\nkernel/module/main.c-1106-\nkernel/module/main.c:1107:int try_to_force_load(struct module *mod, const char *reason)\nkernel/module/main.c-1108-{\n--\nkernel/module/main.c=2909=bool __weak module_elf_check_arch(Elf_Ehdr *hdr)\n--\nkernel/module/main.c-2913-\nkernel/module/main.c:2914:int __weak module_frob_arch_sections(Elf_Ehdr *hdr,\nkernel/module/main.c-2915-\t\t\t\t Elf_Shdr *sechdrs,\n--\nkernel/module/main.c=3012=static void module_deallocate(struct module *mod, struct load_info *info)\n--\nkernel/module/main.c-3020-\nkernel/module/main.c:3021:int __weak module_finalize(const Elf_Ehdr *hdr,\nkernel/module/main.c-3022-\t\t\t const Elf_Shdr *sechdrs,\n--\nkernel/module/signing.c=43=int mod_verify_sig(const void *mod, struct load_info *info)\n--\nkernel/module/signing.c-69-\nkernel/module/signing.c:70:int module_sig_check(struct load_info *info, int flags)\nkernel/module/signing.c-71-{\n--\nkernel/module/stats.c=230=void mod_stat_bump_becoming(struct load_info *info, int flags)\n--\nkernel/module/stats.c-239-\nkernel/module/stats.c:240:int try_add_failed_module(const char *name, enum fail_dup_mod_reason reason)\nkernel/module/stats.c-241-{\n--\nkernel/module/strict_rwx.c=15=static int module_set_memory(const struct module *mod, enum mod_mem_type type,\n--\nkernel/module/strict_rwx.c-32- */\nkernel/module/strict_rwx.c:33:int module_enable_text_rox(const struct module *mod)\nkernel/module/strict_rwx.c-34-{\n--\nkernel/module/strict_rwx.c-50-\nkernel/module/strict_rwx.c:51:int module_enable_rodata_ro(const struct module *mod)\nkernel/module/strict_rwx.c-52-{\n--\nkernel/module/strict_rwx.c-67-\nkernel/module/strict_rwx.c:68:int module_enable_rodata_ro_after_init(const struct module *mod)\nkernel/module/strict_rwx.c-69-{\n--\nkernel/module/strict_rwx.c-75-\nkernel/module/strict_rwx.c:76:int module_enable_data_nx(const struct module *mod)\nkernel/module/strict_rwx.c-77-{\n--\nkernel/module/strict_rwx.c-89-\nkernel/module/strict_rwx.c:90:int module_enforce_rwx_sections(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,\nkernel/module/strict_rwx.c-91-\t\t\t\tconst char *secstrings,\n--\nkernel/module/sysfs.c=332=static int mod_sysfs_init(struct module *mod)\n--\nkernel/module/sysfs.c-363-\nkernel/module/sysfs.c:364:int mod_sysfs_setup(struct module *mod,\nkernel/module/sysfs.c-365-\t\t const struct load_info *info,\n--\nkernel/module/tracking.c=18=extern struct dentry *mod_debugfs_root;\nkernel/module/tracking.c-19-\nkernel/module/tracking.c:20:int try_add_tainted_module(struct module *mod)\nkernel/module/tracking.c-21-{\n"
} |
| 29/2 | 2026/08/12 06:11 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 19157 output: 30 thoughts: 456 Thoughts: **Analyzing Module Loading Entry Points** Okay, so I'm digging into these module loading changes, and the initial thought was to jump straight into the functions where the actual modifications seem to be, which are `layout_and_allocate`, `reserve_module_tags`, and `release_module_tags`. But those are static functions, internal helpers, not what we're looking for, I need the actual API entry points. That's a key detail! Right, so the obvious starting point, the syscalls themselves. The initial idea was to focus on `sys_init_module` and `sys_finit_module`. That makes more sense, and then I was getting slightly thrown by the internal `load_module` being static and the main work happening there. But, wait, no, `init_module` and `finit_module` are the syscalls, and they're what Syzkaller should be using in the test harness. Let's make sure I'm using the correct names for the syscalls. Ah, yes, `sys_init_module` and `sys_finit_module`, or sometimes just `init_module` or `finit_module`, are what Syzkaller would be looking for. That seems right. Perfect. Let's confirm that these are the proper names. Yes, Syzkaller uses `sys_init_module`. Okay, that's good. Remember the prompt: we're favoring non-static, non-inlined API entrypoints over internal helper functions. So, `sys_init_module` and `sys_finit_module` are definitely the preferred entry points. Now, let's just make sure there aren't any other non-static functions involved here that I'm missing. `alloc_tag_init` is `__init` and static. `reserve_module_tags` and `release_module_tags` are static as well, so that confirms it. The only entry points are definitely the module loading syscalls, `sys_init_module` and `sys_finit_module`. That's where I need to focus my attention. Now I need to check whether `MEM_ALLOC_PROFILING` needs any other configurations to be enabled. |
| 30/2 | 2026/08/12 06:11 | tool | grepper |
0mArgs:{
"Expression": "config MEM_ALLOC_PROFILING",
"PathPrefix": "mm/"
}Results: {
"Output": "mm/Kconfig.debug=311=config PER_VMA_LOCK_STATS\n--\nmm/Kconfig.debug-323-\nmm/Kconfig.debug:324:config MEM_ALLOC_PROFILING\nmm/Kconfig.debug-325-\tbool \"Enable memory allocation profiling\"\n--\nmm/Kconfig.debug-337-\nmm/Kconfig.debug:338:config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT\nmm/Kconfig.debug-339-\tbool \"Enable memory allocation profiling by default\"\n--\nmm/Kconfig.debug-342-\nmm/Kconfig.debug:343:config MEM_ALLOC_PROFILING_DEBUG\nmm/Kconfig.debug-344-\tbool \"Memory allocation profiler debugging\"\n"
} |
| 31/2 | 2026/08/12 06:11 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 20329 output: 34 thoughts: 19 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Diving into Debug Configuration** Okay, so I'm thinking, where's the best place to dig into these debug options? My instinct is to check `mm/Kconfig.debug`. That's usually the go-to spot for memory management-related debugging configurations, especially around the core memory areas. I'm specifically aiming around line 324; that feels like a likely point to start unraveling what's enabled and disabled. My hope is to get a clearer picture of which features are active in the current build and understand how they interact with each other, right in the configuration space. I anticipate there'll be conditional blocks and some interesting dependencies in that area. It's time to get a better grasp on what can be adjusted, and how it impacts the runtime environment. |
| 32/2 | 2026/08/12 06:11 | tool | read-file |
0mArgs:{
"File": "mm/Kconfig.debug",
"FirstLine": 315,
"LineCount": 30
}Results: {
"Contents": " 315:\t\t Say Y here to enable success, retry and failure counters of page\n 316:\t\t faults handled under protection of per-vma locks. When enabled, the\n 317:\t\t counters are exposed in /proc/vmstat. This information is useful for\n 318:\t\t kernel developers to evaluate effectiveness of per-vma locks and to\n 319:\t\t identify pathological cases. Counting these events introduces a small\n 320:\t\t overhead in the page fault path.\n 321:\t\n 322:\t\t If in doubt, say N.\n 323:\t\n 324:\tconfig MEM_ALLOC_PROFILING\n 325:\t\tbool \"Enable memory allocation profiling\"\n 326:\t\tdefault n\n 327:\t\tdepends on MMU\n 328:\t\tdepends on PROC_FS\n 329:\t\tdepends on !DEBUG_FORCE_WEAK_PER_CPU\n 330:\t\tselect CODE_TAGGING\n 331:\t\tselect PAGE_EXTENSION\n 332:\t\tselect SLAB_OBJ_EXT\n 333:\t\thelp\n 334:\t\t Track allocation source code and record total allocation size\n 335:\t\t initiated at that code location. The mechanism can be used to track\n 336:\t\t memory leaks with a low performance and memory impact.\n 337:\t\n 338:\tconfig MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT\n 339:\t\tbool \"Enable memory allocation profiling by default\"\n 340:\t\tdefault y\n 341:\t\tdepends on MEM_ALLOC_PROFILING\n 342:\t\n 343:\tconfig MEM_ALLOC_PROFILING_DEBUG\n 344:\t\tbool \"Memory allocation profiler debugging\"\n"
} |
| 33/2 | 2026/08/12 06:11 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 21021 output: 27 thoughts: 318 Thoughts: **Kernel Configuration and Syscall Verification** Okay, let's see. I'm looking at enabling `MEM_ALLOC_PROFILING`. The dependencies are pretty clear: `MMU`, `PROC_FS`, and importantly, it needs to be *not* `DEBUG_FORCE_WEAK_PER_CPU`. That makes sense. And when enabled, it pulls in `CODE_TAGGING`, `PAGE_EXTENSION`, and `SLAB_OBJ_EXT`. So, I think we should enable `MEM_ALLOC_PROFILING`. I don't see any other direct configuration items. Ah, good! `MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT` is `default y` as long as `MEM_ALLOC_PROFILING` is set. So, just setting `MEM_ALLOC_PROFILING` should be enough. Great. Now, a quick verification on the syscalls. Let's make sure the names are right. I need to confirm `sys_init_module` and `sys_finit_module` are the correct names. They are defined with `SYSCALL_DEFINE3`, and they are named according to the architecture. Specifically `__x64_sys_init_module` or `sys_init_module` depending on the architecture. Syzkaller uses `init_module` and `finit_module`. So, for `FocusSymbols`, we'll provide `sys_init_module` and `sys_finit_module` because it simplifies things. Wait a second, hold on... `load_module`... It's the main function, even though it's static. It's a huge function, a key piece of the module loading process. I need to check if `load_module` is inlined because that would impact the symbol visibility and how it's handled. That warrants further investigation. |
| 34/2 | 2026/08/12 06:11 | tool | grepper |
0mArgs:{
"Expression": "load_module",
"PathPrefix": "kernel/module/"
}Results: {
"Output": "kernel/module/debug_kmemleak.c-11-\nkernel/module/debug_kmemleak.c:12:void kmemleak_load_module(const struct module *mod,\nkernel/module/debug_kmemleak.c-13-\t\t\t const struct load_info *info)\n--\nkernel/module/internal.h=62=struct load_info {\nkernel/module/internal.h-63-\tconst char *name;\nkernel/module/internal.h:64:\t/* pointer to module in temporary copy, freed at end of load_module() */\nkernel/module/internal.h-65-\tstruct module *mod;\n--\nkernel/module/internal.h=342=static inline int module_sig_check(struct load_info *info, int flags)\n--\nkernel/module/internal.h-348-#ifdef CONFIG_DEBUG_KMEMLEAK\nkernel/module/internal.h:349:void kmemleak_load_module(const struct module *mod, const struct load_info *info);\nkernel/module/internal.h-350-#else /* !CONFIG_DEBUG_KMEMLEAK */\nkernel/module/internal.h:351:static inline void kmemleak_load_module(const struct module *mod,\nkernel/module/internal.h-352-\t\t\t\t\tconst struct load_info *info) { }\n--\nkernel/module/main.c=1417=static void free_module(struct module *mod)\n--\nkernel/module/main.c-1420-\nkernel/module/main.c:1421:\tcodetag_unload_module(mod);\nkernel/module/main.c-1422-\n--\nkernel/module/main.c=2943=static struct module *layout_and_allocate(struct load_info *info, int flags)\n--\nkernel/module/main.c-3004-\tmod = (void *)info-\u003esechdrs[info-\u003eindex.mod].sh_addr;\nkernel/module/main.c:3005:\tkmemleak_load_module(mod, info);\nkernel/module/main.c-3006-\tcodetag_module_replaced(info-\u003emod, mod);\n--\nkernel/module/main.c=3407=static int early_mod_check(struct load_info *info, int flags)\n--\nkernel/module/main.c-3442- */\nkernel/module/main.c:3443:static int load_module(struct load_info *info, const char __user *uargs,\nkernel/module/main.c-3444-\t\t int flags)\n--\nkernel/module/main.c-3591-\nkernel/module/main.c:3592:\tif (codetag_load_module(mod))\nkernel/module/main.c-3593-\t\tgoto sysfs_cleanup;\n--\nkernel/module/main.c=3655=SYSCALL_DEFINE3(init_module, void __user *, umod,\n--\nkernel/module/main.c-3674-\nkernel/module/main.c:3675:\treturn load_module(\u0026info, uargs, 0);\nkernel/module/main.c-3676-}\n--\nkernel/module/main.c=3762=static int init_module_from_file(struct file *f, const char __user * uargs, int flags)\n--\nkernel/module/main.c-3797-\nkernel/module/main.c:3798:\treturn load_module(\u0026info, uargs, flags);\nkernel/module/main.c-3799-}\n--\nkernel/module/stats.c=100=static LIST_HEAD(dup_failed_modules);\n--\nkernel/module/stats.c-183- * call layout_and_allocate() for it.\nkernel/module/stats.c:184: * * failed_load_modules: how many modules failed once we've allocated our\nkernel/module/stats.c-185- * private space for our module using layout_and_allocate(). These failures\n--\nkernel/module/stats.c=205=static atomic_t failed_becoming;\nkernel/module/stats.c:206:static atomic_t failed_load_modules;\nkernel/module/stats.c-207-\n--\nkernel/module/stats.c=220=void mod_stat_bump_invalid(struct load_info *info, int flags)\n--\nkernel/module/stats.c-222-\tatomic_long_add(info-\u003elen * 2, \u0026invalid_mod_bytes);\nkernel/module/stats.c:223:\tatomic_inc(\u0026failed_load_modules);\nkernel/module/stats.c-224-#if defined(CONFIG_MODULE_DECOMPRESS)\n--\nkernel/module/stats.c=273=static ssize_t read_file_mod_stats(struct file *file, char __user *user_buf,\n--\nkernel/module/stats.c-287-\tfbecoming = atomic_read(\u0026failed_becoming);\nkernel/module/stats.c:288:\tfloads = atomic_read(\u0026failed_load_modules);\nkernel/module/stats.c-289-\n--\nkernel/module/stats.c=411=static int __init module_stats_init(void)\n--\nkernel/module/stats.c-423-\tmod_debug_add_atomic(failed_becoming);\nkernel/module/stats.c:424:\tmod_debug_add_atomic(failed_load_modules);\nkernel/module/stats.c-425-\n"
} |
| 35/2 | 2026/08/12 06:11 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 23180 output: 147 thoughts: 435 Thoughts: **My Analysis of the Module Loading Patch** Okay, here's the breakdown. The code's interesting because `load_module` is static but enormous. The prompt explicitly favors non-static, non-inlined API entrypoints. Since `sys_init_module` and `sys_finit_module` are the true entry points, and according to the documentation they are non-static and non-inlined, I should be using them. Wait, hold on, `sys_init_module` is a macro, so it could be `__x64_sys_init_module` or `sys_init_module`. It sounds like syzkaller generally understands `sys_init_module` and `sys_finit_module`, so that should be fine. I'll stick with `sys_init_module` and `sys_finit_module`. Now, let's look at what's actually changed within `mm/alloc_tag.c`. I see modifications to `reserve_module_tags` and `release_module_tags`. Those are static functions, so I'm not directly targeting them, but they're important. The configuration variable `MEM_ALLOC_PROFILING` is clearly relevant here. Is there any other config? The obvious requirement is `MODULES`, but that's typically enabled in most fuzzing setups, so I won't worry about it. I *will* be including `MEM_ALLOC_PROFILING`, though. So, here's my summary: * **WorthFuzzing:** True – this is a core module loader change. * **FocusSymbols:** `sys_init_module`, `sys_finit_module` – these are the entry points. * **EnableConfigs:** `MEM_ALLOC_PROFILING` – this enables the relevant code path. * **Reasoning:** The patch modifies the module loading logic to handle memory allocation profiling tags when they cannot fit in page flag bits. It adds a retry loop to `layout_and_allocate` when `move_module` returns `-EAGAIN`. This represents a functional change in the module loader, reachable via `init_module` and `finit_module` syscalls when `CONFIG_MEM_ALLOC_PROFILING` is enabled. |
| 36/2 | 2026/08/12 06:11 | tool | set-results |
0mArgs:{
"EnableConfigs": [
"MEM_ALLOC_PROFILING"
],
"FocusSymbols": [
"sys_init_module",
"sys_finit_module"
],
"Reasoning": "The patch modifies the module loading logic to handle a case where memory allocation profiling tags cannot fit in page flag bits. It adds a retry loop in `layout_and_allocate` when `move_module` returns `-EAGAIN`. This is a functional change in the core module loader that is reachable via `init_module` and `finit_module` syscalls when `CONFIG_MEM_ALLOC_PROFILING` is enabled.",
"WorthFuzzing": true
}Results: {
"EnableConfigs": [
"MEM_ALLOC_PROFILING"
],
"FocusSymbols": [
"sys_init_module",
"sys_finit_module"
],
"Reasoning": "The patch modifies the module loading logic to handle a case where memory allocation profiling tags cannot fit in page flag bits. It adds a retry loop in `layout_and_allocate` when `move_module` returns `-EAGAIN`. This is a functional change in the core module loader that is reachable via `init_module` and `finit_module` syscalls when `CONFIG_MEM_ALLOC_PROFILING` is enabled.",
"WorthFuzzing": true
} |
| 37/1 | 2026/08/12 06:11 | action | If |
0mArgs:{
"WorthFuzzing": true
}Results: null |
| 38/2 | 2026/08/12 06:11 | agent | kmsan-evaluator |
0mModel:best-expensive Args: null Results: {
"KMSANReasoning": "The patch modifies module loading to handle the case where memory allocation profiling tags exceed the available page flag bits. It introduces a retry mechanism in `layout_and_allocate()` by returning `-EAGAIN` from `move_module()` (via `reserve_module_tags()`). The state is saved in a local stack array `frob_size` which is fully initialized using the `for_each_mod_mem_type` macro (iterating over all valid module memory types). The patch also moves `release_module_tags()` earlier in the file to be called during the error path. There are no new structures copied to user space, no complex uninitialized data structures, and no changes to bounds checking that could expose uninitialized memory. Any potential bugs introduced would be logic errors or memory leaks, which are adequately covered by standard KASAN and other bug detectors.",
"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 9f2048479c5c5ae184cf4b18c328c88f02748f5d
Author: syz-cluster <triage@syzkaller.com>
Date: Wed Aug 12 06:09:56 2026 +0000
syz-cluster: applied patch under review
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 46dd8d25a6058..ed26f167be84d 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2944,6 +2944,7 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
{
struct module *mod;
int err;
+ unsigned long frob_size[MOD_MEM_NUM_TYPES];
/* Allow arches to frob section contents and sizes. */
err = module_frob_arch_sections(info->hdr, info->sechdrs,
@@ -2966,18 +2967,38 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
*/
module_mark_ro_after_init(info->hdr, info->sechdrs, info->secstrings);
+ /*
+ * Save the sizes reserved by module_frob_arch_sections() so they can
+ * be restored if we retry below.
+ */
+ for_each_mod_mem_type(type)
+ frob_size[type] = info->mod->mem[type].size;
+
/*
* Determine total sizes, and put offsets in sh_entsize. For now
* this is done generically; there doesn't appear to be any
* special cases for the architectures.
*/
+retry:
layout_sections(info->mod, info);
layout_symtab(info->mod, info);
/* Allocate and move to the final place */
err = move_module(info->mod, info);
- if (err)
- return ERR_PTR(err);
+ if (err) {
+ if (err != -EAGAIN)
+ return ERR_PTR(err);
+ /*
+ * -EAGAIN means profiling was disabled but the module
+ * can still load without it. Reset state and retry.
+ */
+ rewrite_section_headers(info, flags);
+ for_each_mod_mem_type(type)
+ info->mod->mem[type].size = frob_size[type];
+ info->sechdrs[info->index.sym].sh_flags &= ~(unsigned long)SHF_ALLOC;
+ info->sechdrs[info->index.str].sh_flags &= ~(unsigned long)SHF_ALLOC;
+ goto retry;
+ }
/* Module has been copied to its final place now: return it. */
mod = (void *)info->sechdrs[info->index.mod].sh_addr;
diff --git a/mm/alloc_tag.c b/mm/alloc_tag.c
index b334103104779..112a014d4b890 100644
--- a/mm/alloc_tag.c
+++ b/mm/alloc_tag.c
@@ -835,6 +835,52 @@ static int vm_module_tags_populate(void)
return 0;
}
+static void release_module_tags(struct module *mod, bool used)
+{
+ MA_STATE(mas, &mod_area_mt, module_tags.size, module_tags.size);
+ struct alloc_tag *start_tag;
+ struct alloc_tag *end_tag;
+ struct module *val;
+
+ mas_lock(&mas);
+ mas_for_each_rev(&mas, val, 0)
+ if (val == mod)
+ break;
+
+ if (!val) /* module not found */
+ goto out;
+
+ if (!used)
+ goto release_area;
+
+ start_tag = (struct alloc_tag *)(module_tags.start_addr + mas.index);
+ end_tag = (struct alloc_tag *)(module_tags.start_addr + mas.last);
+ if (!clean_unused_counters(start_tag, end_tag)) {
+ struct alloc_tag *tag;
+
+ for (tag = start_tag; tag <= end_tag; tag++) {
+ struct alloc_tag_counters counter;
+
+ if (!tag->counters)
+ continue;
+
+ counter = alloc_tag_read(tag);
+ pr_info("%s:%u module %s func:%s has %llu allocated at module unload\n",
+ tag->ct.filename, tag->ct.lineno, tag->ct.modname,
+ tag->ct.function, counter.bytes);
+ }
+ } else {
+ used = false;
+ }
+release_area:
+ mas_store(&mas, used ? &unloaded_mod : NULL);
+ val = mas_prev_range(&mas, 0);
+ if (val == &prepend_mod)
+ mas_store(&mas, NULL);
+out:
+ mas_unlock(&mas);
+}
+
static void *reserve_module_tags(struct module *mod, unsigned long size,
unsigned int prepend, unsigned long align)
{
@@ -904,10 +950,12 @@ static void *reserve_module_tags(struct module *mod, unsigned long size,
int grow_res;
module_tags.size = offset + size;
- if (mem_alloc_profiling_enabled() && !tags_addressable()) {
+ if (!tags_addressable()) {
shutdown_mem_profiling(true);
- pr_warn("With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\n",
- mod->name, NR_UNUSED_PAGEFLAG_BITS);
+ pr_warn_once("With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\n",
+ mod->name, NR_UNUSED_PAGEFLAG_BITS);
+ release_module_tags(mod, false);
+ return ERR_PTR(-EAGAIN);
}
grow_res = vm_module_tags_populate();
@@ -922,52 +970,6 @@ static void *reserve_module_tags(struct module *mod, unsigned long size,
return (struct alloc_tag *)(module_tags.start_addr + offset);
}
-static void release_module_tags(struct module *mod, bool used)
-{
- MA_STATE(mas, &mod_area_mt, module_tags.size, module_tags.size);
- struct alloc_tag *start_tag;
- struct alloc_tag *end_tag;
- struct module *val;
-
- mas_lock(&mas);
- mas_for_each_rev(&mas, val, 0)
- if (val == mod)
- break;
-
- if (!val) /* module not found */
- goto out;
-
- if (!used)
- goto release_area;
-
- start_tag = (struct alloc_tag *)(module_tags.start_addr + mas.index);
- end_tag = (struct alloc_tag *)(module_tags.start_addr + mas.last);
- if (!clean_unused_counters(start_tag, end_tag)) {
- struct alloc_tag *tag;
-
- for (tag = start_tag; tag <= end_tag; tag++) {
- struct alloc_tag_counters counter;
-
- if (!tag->counters)
- continue;
-
- counter = alloc_tag_read(tag);
- pr_info("%s:%u module %s func:%s has %llu allocated at module unload\n",
- tag->ct.filename, tag->ct.lineno, tag->ct.modname,
- tag->ct.function, counter.bytes);
- }
- } else {
- used = false;
- }
-release_area:
- mas_store(&mas, used ? &unloaded_mod : NULL);
- val = mas_prev_range(&mas, 0);
- if (val == &prepend_mod)
- mas_store(&mas, NULL);
-out:
- mas_unlock(&mas);
-}
-
static int load_module(struct module *mod, struct codetag *start, struct codetag *stop)
{
/* Allocate module alloc_tag percpu counters */
|
| 39/3 | 2026/08/12 06:11 | llm | kmsan-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 3924 output: 25 thoughts: 395 Thoughts: **Analyzing a Module Loading Patch** Okay, so I'm looking at this patch that tweaks how modules are loaded, specifically dealing with `-EAGAIN` errors that can pop up during tag allocation. It looks like the core issue is that `reserve_module_tags()` can fail because we're trying to cram too many tags into the page flag bits. When that happens, the patch disables memory allocation profiling, releases the tags, and bails out with `-EAGAIN`. `layout_and_allocate()` in `kernel/module/main.c` then catches the error, resets things, and tries again without using tags. That's the basic flow. But now, I see something new: the patch introduces this `frob_size` array within `layout_and_allocate()`. It's an `unsigned long` array of `MOD_MEM_NUM_TYPES` (which I know is 7 from past experience) elements. The code is saving `info->mod->mem[type].size` into `frob_size` *before* `layout_sections()` is called. Then, if `move_module()` returns `-EAGAIN`, it restores `info->mod->mem[type].size` from `frob_size[type]`, clears `SHF_ALLOC` from some sections, and jumps to `retry`. Makes sense, the size of memory regions are saved prior to potential failure, then restored after failure to restart layout. The red flag is always uninitialized memory. Is this `frob_size` initialized correctly? It is filled in a loop: ```c for_each_mod_mem_type(type) frob_size[type] = info->mod->mem[type].size; ``` I have to be careful here... The loop iterates over all "valid" module memory types. What constitutes "valid" in this context? If some of those 7 elements aren't initialized, we could be reading garbage when restoring the sizes! I need to double-check that `for_each_mod_mem_type` macro definition to make absolutely sure. Any vulnerability here would create a serious security risk. |
| 40/3 | 2026/08/12 06:11 | tool | grepper |
0mArgs:{
"Expression": "#define for_each_mod_mem_type"
}Results: {
"Output": "include/linux/module.h=318=enum mod_mem_type {\n--\ninclude/linux/module.h-347-\ninclude/linux/module.h:348:#define for_each_mod_mem_type(type)\t\t\t\\\ninclude/linux/module.h-349-\tfor (enum mod_mem_type (type) = 0;\t\t\\\n"
} |
| 41/3 | 2026/08/12 06:11 | llm | kmsan-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 4914 output: 23 thoughts: 19 Thoughts: Okay, here's my attempt at summarizing my thought process regarding `for_each_mod_mem_type`, as if I were thinking it: **Diving into `for_each_mod_mem_type`** Alright, let's get down to brass tacks. I need the complete picture on this `for_each_mod_mem_type` function or macro or whatever it is. I can't really assess its significance or how I might leverage it effectively without a proper definition. I need to understand its parameters, its return type (if any), and most importantly, what it *does* under the hood. What is it iterating over? What kind of memory types is it handling? Is it related to modules or some sort of underlying memory model? This is probably a low-level routine, so the details are going to be key to a proper understanding. I need the full context to make any useful judgments about its usefulness and application. Time to dig in and find that definition. |
| 42/3 | 2026/08/12 06:11 | tool | grepper |
0mArgs:{
"Expression": "for_each_mod_mem_type"
}Results: {
"Output": ".clang-format=71=ForEachMacros:\n--\n.clang-format-336- - 'for_each_mle_subelement'\n.clang-format:337: - 'for_each_mod_mem_type'\n.clang-format-338- - 'for_each_mon_capable_rdt_resource'\n--\ninclude/linux/module.h=318=enum mod_mem_type {\n--\ninclude/linux/module.h-347-\ninclude/linux/module.h:348:#define for_each_mod_mem_type(type)\t\t\t\\\ninclude/linux/module.h-349-\tfor (enum mod_mem_type (type) = 0;\t\t\\\n--\ninclude/linux/module.h-352-#define for_class_mod_mem_type(type, class)\t\t\\\ninclude/linux/module.h:353:\tfor_each_mod_mem_type(type)\t\t\t\\\ninclude/linux/module.h-354-\t\tif (mod_mem_type_is_##class(type))\n--\nkernel/module/debug_kmemleak.c=12=void kmemleak_load_module(const struct module *mod,\n--\nkernel/module/debug_kmemleak.c-15-\t/* only scan writable, non-executable sections */\nkernel/module/debug_kmemleak.c:16:\tfor_each_mod_mem_type(type) {\nkernel/module/debug_kmemleak.c-17-\t\tif (type != MOD_DATA \u0026\u0026 type != MOD_INIT_DATA \u0026\u0026\n--\nkernel/module/main.c=119=static void mod_update_bounds(struct module *mod)\nkernel/module/main.c-120-{\nkernel/module/main.c:121:\tfor_each_mod_mem_type(type) {\nkernel/module/main.c-122-\t\tstruct module_memory *mod_mem = \u0026mod-\u003emem[type];\n--\nkernel/module/main.c=1397=static void free_mod_mem(struct module *mod)\nkernel/module/main.c-1398-{\nkernel/module/main.c:1399:\tfor_each_mod_mem_type(type) {\nkernel/module/main.c-1400-\t\tstruct module_memory *mod_mem = \u0026mod-\u003emem[type];\n--\nkernel/module/main.c=2788=static int move_module(struct module *mod, struct load_info *info)\n--\nkernel/module/main.c-2793-\nkernel/module/main.c:2794:\tfor_each_mod_mem_type(type) {\nkernel/module/main.c-2795-\t\tif (!mod-\u003emem[type].size) {\n--\nkernel/module/main.c=2892=static void flush_module_icache(const struct module *mod)\n--\nkernel/module/main.c-2898-\t */\nkernel/module/main.c:2899:\tfor_each_mod_mem_type(type) {\nkernel/module/main.c-2900-\t\tconst struct module_memory *mod_mem = \u0026mod-\u003emem[type];\n--\nkernel/module/main.c=2943=static struct module *layout_and_allocate(struct load_info *info, int flags)\n--\nkernel/module/main.c-2973-\t */\nkernel/module/main.c:2974:\tfor_each_mod_mem_type(type)\nkernel/module/main.c-2975-\t\tfrob_size[type] = info-\u003emod-\u003emem[type].size;\n--\nkernel/module/main.c-2995-\t\trewrite_section_headers(info, flags);\nkernel/module/main.c:2996:\t\tfor_each_mod_mem_type(type)\nkernel/module/main.c-2997-\t\t\tinfo-\u003emod-\u003emem[type].size = frob_size[type];\n--\nkernel/module/main.c=3098=static noinline int do_init_module(struct module *mod)\n--\nkernel/module/main.c-3104-\nkernel/module/main.c:3105:\tfor_each_mod_mem_type(type) {\nkernel/module/main.c-3106-\t\tconst struct module_memory *mod_mem = \u0026mod-\u003emem[type];\n--\nkernel/module/procfs.c=65=static unsigned int module_total_size(struct module *mod)\n--\nkernel/module/procfs.c-68-\nkernel/module/procfs.c:69:\tfor_each_mod_mem_type(type)\nkernel/module/procfs.c-70-\t\tsize += mod-\u003emem[type].size;\n--\nkernel/module/tree_lookup.c=78=void mod_tree_insert(struct module *mod)\nkernel/module/tree_lookup.c-79-{\nkernel/module/tree_lookup.c:80:\tfor_each_mod_mem_type(type) {\nkernel/module/tree_lookup.c-81-\t\tmod-\u003emem[type].mtn.mod = mod;\n--\nkernel/module/tree_lookup.c=95=void mod_tree_remove(struct module *mod)\nkernel/module/tree_lookup.c-96-{\nkernel/module/tree_lookup.c:97:\tfor_each_mod_mem_type(type) {\nkernel/module/tree_lookup.c-98-\t\tif (mod-\u003emem[type].size)\n"
} |
| 43/3 | 2026/08/12 06:11 | llm | kmsan-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 6581 output: 35 thoughts: 23 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Diving into Module Initialization** Okay, so I'm thinking I need to refresh my memory on module initialization procedures. Specifically, I'm going to take a look at the definition of `module.h` in the Linux kernel headers. I'm going to start by going to lines 348 through 351, which should get me started on the specifics of how the kernel manages module load and unload routines. I'm interested in those lines, because I know they're critical for understanding the mechanics of how the kernel handles the module lifecycle from the developer's perspective. I expect to see the key structures and macros involved. This should give me a solid foundation. |
| 44/3 | 2026/08/12 06:11 | tool | read-file |
0mArgs:{
"File": "include/linux/module.h",
"FirstLine": 345,
"LineCount": 10
}Results: {
"Contents": " 345:\t\t(mod_mem_type_is_core(type) \u0026\u0026\t\\\n 346:\t\t mod_mem_type_is_data(type))\n 347:\t\n 348:\t#define for_each_mod_mem_type(type)\t\t\t\\\n 349:\t\tfor (enum mod_mem_type (type) = 0;\t\t\\\n 350:\t\t (type) \u003c MOD_MEM_NUM_TYPES; (type)++)\n 351:\t\n 352:\t#define for_class_mod_mem_type(type, class)\t\t\\\n 353:\t\tfor_each_mod_mem_type(type)\t\t\t\\\n 354:\t\t\tif (mod_mem_type_is_##class(type))\n"
} |
| 45/3 | 2026/08/12 06:11 | llm | kmsan-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 7009 output: 205 thoughts: 871 Thoughts: **Uninitialized Memory Risk Assessment** Alright, let's break this down. First, regarding the initial concern about `frob_size`, it's clear after examining the code that it's a local, stack-allocated array. The loop using `for_each_mod_mem_type` *does* initialize all elements of `frob_size` before it's used. Therefore, the restoration of `info->mod->mem[type].size` using `frob_size` is perfectly safe – no uninitialized memory issues there. We're good. Now, let's consider the `mm/alloc_tag.c` patch. The primary focus here seems to be on `release_module_tags` and its interaction with the `module_tags` structure. The function iterates through module tags to clean up unused counters, and it reads `tag->counters` in the process, printing information if those counters haven't been cleaned up. The crucial thing here is to confirm there's no risk of reading uninitialized memory. A quick review of the diff reveals that `release_module_tags` was moved up in the file. This move makes it easier to call it from `reserve_module_tags`. In `reserve_module_tags`, the patch includes error handling. If the number of tags needed exceeds the available bits, the code now calls `release_module_tags` *before* returning `-EAGAIN`. This effectively retries module loading without allocation of profiling tags. Critically, the core logic here is about *failing* gracefully when resources are constrained. This patch primarily restores module sizes and retries without allocating tags, and I can confirm that there is no risk of uninitialized memory being exposed by this change, given the logic. Therefore, because this patch addresses module loading retry when memory allocation profiling tags exceed limits and does not involve user-space copies or complex data structures, I conclude that `NeedsKMSAN=false`. |
| 46/3 | 2026/08/12 06:12 | tool | set-results |
0mArgs:{
"KMSANReasoning": "The patch modifies module loading to handle the case where memory allocation profiling tags exceed the available page flag bits. It introduces a retry mechanism in `layout_and_allocate()` by returning `-EAGAIN` from `move_module()` (via `reserve_module_tags()`). The state is saved in a local stack array `frob_size` which is fully initialized using the `for_each_mod_mem_type` macro (iterating over all valid module memory types). The patch also moves `release_module_tags()` earlier in the file to be called during the error path. There are no new structures copied to user space, no complex uninitialized data structures, and no changes to bounds checking that could expose uninitialized memory. Any potential bugs introduced would be logic errors or memory leaks, which are adequately covered by standard KASAN and other bug detectors.",
"NeedsKMSAN": false
}Results: {
"KMSANReasoning": "The patch modifies module loading to handle the case where memory allocation profiling tags exceed the available page flag bits. It introduces a retry mechanism in `layout_and_allocate()` by returning `-EAGAIN` from `move_module()` (via `reserve_module_tags()`). The state is saved in a local stack array `frob_size` which is fully initialized using the `for_each_mod_mem_type` macro (iterating over all valid module memory types). The patch also moves `release_module_tags()` earlier in the file to be called during the error path. There are no new structures copied to user space, no complex uninitialized data structures, and no changes to bounds checking that could expose uninitialized memory. Any potential bugs introduced would be logic errors or memory leaks, which are adequately covered by standard KASAN and other bug detectors.",
"NeedsKMSAN": false
} |
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