| Seq | Timestamp | Type | Name | Duration |
|---|---|---|---|---|
| 0/0 | 2026/10/26 01:42 | flow | patch-triage |
0mArgs:null Results: {
"EnableConfigs": null,
"FocusSymbols": [],
"KMSANReasoning": "",
"NeedsKMSAN": false,
"Reasoning": "The patch only modifies user-space selftest code (tools/testing/selftests/kvm/arm64/set_id_regs.c) and does not affect the compiled kernel image or kernel modules. Furthermore, it is specific to arm64, whereas the target architecture is amd64.",
"WorthFuzzing": false
} |
| 1/1 | 2026/10/26 01:42 | action | read-patch-diff |
0mArgs:null Results: {
"PatchDiff": "commit 4bf1d4b5971df0a9738b47b6ed5cb024061d9698\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Mon Oct 26 01:42:35 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/tools/testing/selftests/kvm/arm64/set_id_regs.c b/tools/testing/selftests/kvm/arm64/set_id_regs.c\nindex 10849d21c0dd2..1d2cc25cb3f4c 100644\n--- a/tools/testing/selftests/kvm/arm64/set_id_regs.c\n+++ b/tools/testing/selftests/kvm/arm64/set_id_regs.c\n@@ -815,6 +815,10 @@ static void test_idreg_frozen_after_failed_run(void)\n \t\tSYS_REVIDR_EL1,\n \t\tSYS_AIDR_EL1,\n \t};\n+\tu64 masks[KVM_ARM_FEATURE_ID_RANGE_SIZE];\n+\tstruct reg_mask_range range = {\n+\t\t.addr = (__u64)masks,\n+\t};\n \tstruct kvm_vcpu_init init;\n \tstruct kvm_vcpu *vcpu;\n \tstruct kvm_vm *vm;\n@@ -831,6 +835,7 @@ static void test_idreg_frozen_after_failed_run(void)\n \n \tvm = vm_create(1);\n \tvm_enable_cap(vm, KVM_CAP_ARM_WRITABLE_IMP_ID_REGS, 0);\n+\tvm_ioctl(vm, KVM_ARM_GET_REG_WRITABLE_MASKS, \u0026range);\n \tkvm_get_default_vcpu_target(vm, \u0026init);\n \tinit.features[0] |= (1 \u003c\u003c KVM_ARM_VCPU_PMU_V3);\n \tvcpu = aarch64_vcpu_add(vm, 0, \u0026init, guest_code);\n@@ -852,7 +857,9 @@ static void test_idreg_frozen_after_failed_run(void)\n \t */\n \tfor (int i = 0; i \u003c ARRAY_SIZE(test_regs); i++) {\n \t\tconst struct reg_ftr_bits *ftr_bits = test_regs[i].ftr_bits;\n-\t\tu64 reg = KVM_ARM64_SYS_REG(test_regs[i].reg);\n+\t\tu32 reg_id = test_regs[i].reg;\n+\t\tu64 reg = KVM_ARM64_SYS_REG(reg_id);\n+\t\tu64 mask = masks[encoding_to_range_idx(reg_id)];\n \t\tu64 val = vcpu_get_reg(vcpu, reg);\n \n \t\tfor (int j = 0; ftr_bits[j].type != FTR_END; j++) {\n@@ -860,6 +867,10 @@ static void test_idreg_frozen_after_failed_run(void)\n \t\t\tu64 safe = get_safe_value(\u0026ftr_bits[j], ftr);\n \t\t\tu64 new_val;\n \n+\t\t\t/* Only a field userspace could change can be frozen. */\n+\t\t\tif ((mask \u0026 ftr_bits[j].mask) != ftr_bits[j].mask)\n+\t\t\t\tcontinue;\n+\n \t\t\tif (safe == ftr)\n \t\t\t\tcontinue;\n \n"
} |
| 2/1 | 2026/10/26 01:42 | agent | patch-evaluator |
0mModel:core Args: null Results: {
"EnableConfigs": null,
"FocusSymbols": [],
"Reasoning": "The patch only modifies user-space selftest code (tools/testing/selftests/kvm/arm64/set_id_regs.c) and does not affect the compiled kernel image or kernel modules. Furthermore, it is specific to arm64, whereas the target architecture is amd64.",
"WorthFuzzing": false
}Instruction: You are an expert Linux kernel maintainer and security engineer.
Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller.
IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on internal assumptions. You must actively use your code access
tools to inspect the actual source code, callers, and surrounding context.
================================================================================
1. CORE TRIAGE PHILOSOPHY
================================================================================
The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs,
and newly triggered assertions introduced by the patch series.
- REACHABILITY IS THE PRIMARY GATE:
Fuzzing can only discover bugs in code that can actually execute in standard virtualized
environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap).
If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed,
regardless of whether it adds assertions or complex logic.
- DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS:
Patch authors routinely label changes as "cleanups", "refactorings", or state
"No functional change intended". Do NOT take these claims at face value.
Code refactorings that rearrange logic, introduce helper functions, or alter state management
in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs.
If reachable executable code is modified or refactored, it MUST be fuzzed.
- NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED:
When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON*, VM_WARN_ON*,
BUG_ON*, lockdep_assert*) in reachable code paths, it enforces new or stricter invariants.
Even if the author believes the invariant always holds, fuzzing is essential to verify whether
an unusual sequence of operations can violate it.
================================================================================
2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA)
================================================================================
Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories:
- Non-kernel and non-executable changes:
* Modifications to Documentation/, comments, or spelling fixes.
* User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/)
that do not affect the compiled kernel image (vmlinux) or kernel modules.
* Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints
that do not alter control flow or data structures.
* Build system or Kconfig changes that do not alter compiled C logic.
- Structurally unreachable hardware:
* Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed,
ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU.
- Unreachable execution paths:
* Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during
physical PCI hot-unplug or manual sysfs driver unbinding.
* Code paths exclusive to architectures other than the target architecture.
================================================================================
3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA)
================================================================================
Return WorthFuzzing=true whenever the patch touches reachable executable code, including:
- Core Subsystems:
* Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/),
BPF, scheduler, core networking, VFS, or syscall handling.
- Refactorings and Code Cleanups:
* Any restructuring of reachable data structures, helper abstractions, or algorithm flows.
- Runtime Assertions and Defensive Checks:
* Any introduction or alteration of assertions (WARN_ON*, VM_WARN_ON*, BUG_ON*, etc.) in reachable paths.
- Reachable Drivers and Protocols:
* Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.).
================================================================================
4. EXTRACTING FocusSymbols (PREVENTING DILUTION)
================================================================================
When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer:
- AVOID UBIQUITOUS LIFECYCLE HOT-PATHS:
Do NOT list generic, ubiquitous functions called by almost every program in the corpus
(including, but not limited to: general memory allocators and deallocators, page fault
and trap handlers, or core synchronization primitives; this is not an exhaustive list).
Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused",
which severely dilutes fuzzing effort away from the actual changes.
- TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS:
List functions that specifically implement the logic being added or altered, or direct API entrypoints
for the subsystem feature under review.
- HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h):
Compiler-inlined static functions (such as static inlines in mm/*.h or include/linux/*.h) lack
distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters.
If the changes are primarily in static inline helpers, identify non-static, feature-specific caller
functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers).
================================================================================
5. IDENTIFYING EnableConfigs
================================================================================
Identify any specific CONFIG_ options required to properly compile and reach the modified code:
- Inspect Kconfig files and #ifdef guards; do not make assumptions.
- Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed.
- Strip any 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4").
Prefer calling several tools at the same time to save round-trips.
Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.
Prompt: Target architecture: amd64
For your convenience, here is the diff of the changes:
commit 4bf1d4b5971df0a9738b47b6ed5cb024061d9698
Author: syz-cluster <triage@syzkaller.com>
Date: Mon Oct 26 01:42:35 2026 +0000
syz-cluster: applied patch under review
diff --git a/tools/testing/selftests/kvm/arm64/set_id_regs.c b/tools/testing/selftests/kvm/arm64/set_id_regs.c
index 10849d21c0dd2..1d2cc25cb3f4c 100644
--- a/tools/testing/selftests/kvm/arm64/set_id_regs.c
+++ b/tools/testing/selftests/kvm/arm64/set_id_regs.c
@@ -815,6 +815,10 @@ static void test_idreg_frozen_after_failed_run(void)
SYS_REVIDR_EL1,
SYS_AIDR_EL1,
};
+ u64 masks[KVM_ARM_FEATURE_ID_RANGE_SIZE];
+ struct reg_mask_range range = {
+ .addr = (__u64)masks,
+ };
struct kvm_vcpu_init init;
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
@@ -831,6 +835,7 @@ static void test_idreg_frozen_after_failed_run(void)
vm = vm_create(1);
vm_enable_cap(vm, KVM_CAP_ARM_WRITABLE_IMP_ID_REGS, 0);
+ vm_ioctl(vm, KVM_ARM_GET_REG_WRITABLE_MASKS, &range);
kvm_get_default_vcpu_target(vm, &init);
init.features[0] |= (1 << KVM_ARM_VCPU_PMU_V3);
vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code);
@@ -852,7 +857,9 @@ static void test_idreg_frozen_after_failed_run(void)
*/
for (int i = 0; i < ARRAY_SIZE(test_regs); i++) {
const struct reg_ftr_bits *ftr_bits = test_regs[i].ftr_bits;
- u64 reg = KVM_ARM64_SYS_REG(test_regs[i].reg);
+ u32 reg_id = test_regs[i].reg;
+ u64 reg = KVM_ARM64_SYS_REG(reg_id);
+ u64 mask = masks[encoding_to_range_idx(reg_id)];
u64 val = vcpu_get_reg(vcpu, reg);
for (int j = 0; ftr_bits[j].type != FTR_END; j++) {
@@ -860,6 +867,10 @@ static void test_idreg_frozen_after_failed_run(void)
u64 safe = get_safe_value(&ftr_bits[j], ftr);
u64 new_val;
+ /* Only a field userspace could change can be frozen. */
+ if ((mask & ftr_bits[j].mask) != ftr_bits[j].mask)
+ continue;
+
if (safe == ftr)
continue;
|
| 3/2 | 2026/10/26 01:42 | llm | patch-evaluator |
0mModel:gemini-3.8-flash Args: null Results: null Tokens: input: 3629 output: 96 thoughts: 792 Thoughts: **Analysis of the Patch: WorthFuzzing Determination** Okay, let's break this down. First, I need to analyze the provided patch. It looks like we're dealing with a modification to `tools/testing/selftests/kvm/arm64/set_id_regs.c`. That immediately raises a flag. I need to see if this change falls under the "WorthFuzzing=false" criteria from Section 2. The first criterion to check is whether the changes are Non-kernel and non-executable. In this case, it appears we have a user-space directory. It is in `tools/testing/selftests`, which is code that *shouldn't* directly impact the vmlinux or kernel modules. Second point is the target architecture. The fact that the file is located in `kvm/arm64/` while the target architecture is amd64, also points to WorthFuzzing = false. I need to confirm there are no other changes in other files in this commit. Let's see... a quick check of the diff provided should suffice. Hmm, the diff only includes `tools/testing/selftests/kvm/arm64/set_id_regs.c`. That's that. Therefore, since the patch only modifies a selftest within a user-space tools directory (specifically targeting arm64 while the target is amd64), and it doesn't affect the kernel image or modules, it's pretty clear that `WorthFuzzing = false`. I also don't see any reason to set any focus symbols or enable any configs. Let's make that call. |
| 4/2 | 2026/10/26 01:42 | tool | set-results |
0mArgs:{
"EnableConfigs": [],
"FocusSymbols": [],
"Reasoning": "The patch only modifies user-space selftest code (tools/testing/selftests/kvm/arm64/set_id_regs.c) and does not affect the compiled kernel image or kernel modules. Furthermore, it is specific to arm64, whereas the target architecture is amd64.",
"WorthFuzzing": false
}Results: {
"EnableConfigs": null,
"FocusSymbols": [],
"Reasoning": "The patch only modifies user-space selftest code (tools/testing/selftests/kvm/arm64/set_id_regs.c) and does not affect the compiled kernel image or kernel modules. Furthermore, it is specific to arm64, whereas the target architecture is amd64.",
"WorthFuzzing": false
} |
| 5/1 | 2026/10/26 01:42 | action | If |
0mArgs:{
"WorthFuzzing": false
}Results: null |
| Total Calls | Total Tokens | Avg Tokens | Total Duration (Seconds) | Avg Duration (Seconds) |
|---|
| Total Calls | Total Duration (Seconds) | Avg Duration (Seconds) |
|---|