AI Trajectory

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "KMSANReasoning": "",
  "NeedsKMSAN": false,
  "Reasoning": "The patch only modifies files under tools/testing/selftests/ (BPF selftests and test_kmods), which are non-kernel selftests and do not affect the core kernel image (vmlinux) or production kernel modules. Therefore, fuzzing is not warranted.",
  "WorthFuzzing": false
}

null

{
  "PatchDiff": "commit d8463b0928ce9229d1d6885c0895e38eea283839\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Tue Sep 8 08:00:51 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_args.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_args.c\nindex 0f321e8898620..8767e5f8bcc72 100644\n--- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_args.c\n+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_args.c\n@@ -3,7 +3,62 @@\n #include \u003ctest_progs.h\u003e\n #include \"struct_ops_multi_args.skel.h\"\n \n+static void test_refcounted_multi(void)\n+{\n+\tstruct struct_ops_multi_args *skel;\n+\tchar log_buf[4096] = {};\n+\tint err;\n+\n+\tskel = struct_ops_multi_args__open();\n+\tif (!ASSERT_OK_PTR(skel, \"struct_ops_multi_args__open\"))\n+\t\treturn;\n+\n+\tbpf_program__set_log_buf(skel-\u003eprogs.test_refcounted_multi, log_buf, sizeof(log_buf));\n+\n+\terr = struct_ops_multi_args__load(skel);\n+\tif (!ASSERT_EQ(err, -EINVAL, \"struct_ops_multi_args__load\"))\n+\t\tgoto out;\n+\n+\tASSERT_HAS_SUBSTR(log_buf, \"program with __ref argument cannot tail call\",\n+\t\t\t  \"check_verifier_log_message\");\n+\n+out:\n+\tstruct_ops_multi_args__destroy(skel);\n+}\n+\n+static void test_trampoline_stack_args(void)\n+{\n+\tstruct struct_ops_multi_args *skel;\n+\tstruct bpf_link *link = NULL;\n+\tint err;\n+\n+\tskel = struct_ops_multi_args__open();\n+\tif (!ASSERT_OK_PTR(skel, \"struct_ops_multi_args__open\"))\n+\t\treturn;\n+\n+\tbpf_program__set_autoload(skel-\u003eprogs.test_refcounted_multi, false);\n+\tskel-\u003estruct_ops.testmod_ref_acquire-\u003etest_refcounted_multi = NULL;\n+\n+\terr = struct_ops_multi_args__load(skel);\n+\tif (!ASSERT_OK(err, \"struct_ops_multi_args__load\"))\n+\t\tgoto out;\n+\n+\tlink = bpf_map__attach_struct_ops(skel-\u003emaps.testmod_ref_acquire);\n+\tif (!ASSERT_OK_PTR(link, \"bpf_map__attach_struct_ops\"))\n+\t\tgoto out;\n+\n+\tASSERT_EQ(skel-\u003ebss-\u003etrampoline_stack_arg9, 9999, \"check_stack_passed_arg9\");\n+\n+out:\n+\tbpf_link__destroy(link);\n+\tstruct_ops_multi_args__destroy(skel);\n+}\n+\n void test_struct_ops_multi_args(void)\n {\n-\tRUN_TESTS(struct_ops_multi_args);\n+\tif (test__start_subtest(\"test_refcounted_multi\"))\n+\t\ttest_refcounted_multi();\n+\n+\tif (test__start_subtest(\"test_trampoline_stack_args\"))\n+\t\ttest_trampoline_stack_args();\n }\ndiff --git a/tools/testing/selftests/bpf/progs/struct_ops_multi_args.c b/tools/testing/selftests/bpf/progs/struct_ops_multi_args.c\nindex c62be15757f04..9d290f22b4926 100644\n--- a/tools/testing/selftests/bpf/progs/struct_ops_multi_args.c\n+++ b/tools/testing/selftests/bpf/progs/struct_ops_multi_args.c\n@@ -17,7 +17,6 @@ struct {\n } prog_array SEC(\".maps\");\n \n SEC(\"struct_ops/test_refcounted_multi\")\n-__failure __msg(\"program with __ref argument cannot tail call\")\n int test_refcounted_multi(unsigned long long *ctx)\n {\n \t/* ctx[2] is used because the refcounted variable is the third argument */\n@@ -29,7 +28,20 @@ int test_refcounted_multi(unsigned long long *ctx)\n \treturn 0;\n }\n \n+__u64 trampoline_stack_arg9 = 0;\n+\n+SEC(\"struct_ops/test_trampoline_stack_args\")\n+int BPF_PROG(test_trampoline_stack_args, int arg1, int arg2, int arg3,\n+\t\t\t\t\t int arg4, int arg5, int arg6,\n+\t\t\t\t\t int arg7, int arg8, int arg9)\n+{\n+\ttrampoline_stack_arg9 = arg9;\n+\n+\treturn 0;\n+}\n+\n SEC(\".struct_ops.link\")\n struct bpf_testmod_ops testmod_ref_acquire = {\n \t.test_refcounted_multi = (void *)test_refcounted_multi,\n+\t.test_trampoline_stack_args = (void *)test_trampoline_stack_args,\n };\ndiff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c\nindex f798bbbb4d13c..df50b408972ac 100644\n--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c\n+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c\n@@ -1774,6 +1774,8 @@ static int bpf_dummy_reg(void *kdata, struct bpf_link *link)\n \t */\n \tif (ops-\u003etest_2)\n \t\tops-\u003etest_2(4, ops-\u003edata);\n+\tif (ops-\u003etest_trampoline_stack_args)\n+\t\tops-\u003etest_trampoline_stack_args(1, 2, 3, 4, 5, 6, 7, 8, 9999);\n \n \treturn 0;\n }\n@@ -1821,6 +1823,13 @@ bpf_testmod_ops__test_return_ref_kptr(int dummy, struct task_struct *task__ref,\n \treturn NULL;\n }\n \n+static int bpf_testmod_ops__test_trampoline_stack_args(int arg1, int arg2, int arg3,\n+\t\t\t\t\t\t       int arg4, int arg5, int arg6,\n+\t\t\t\t\t\t       int arg7, int arg8, int arg9)\n+{\n+\treturn arg9;\n+}\n+\n static struct bpf_testmod_ops __bpf_testmod_ops = {\n \t.test_1 = bpf_testmod_test_1,\n \t.test_2 = bpf_testmod_test_2,\n@@ -1828,6 +1837,7 @@ static struct bpf_testmod_ops __bpf_testmod_ops = {\n \t.test_refcounted = bpf_testmod_ops__test_refcounted,\n \t.test_refcounted_multi = bpf_testmod_ops__test_refcounted_multi,\n \t.test_return_ref_kptr = bpf_testmod_ops__test_return_ref_kptr,\n+\t.test_trampoline_stack_args = bpf_testmod_ops__test_trampoline_stack_args,\n };\n \n struct bpf_struct_ops bpf_bpf_testmod_ops = {\ndiff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h\nindex 210b919290cc2..2b12f81bf7487 100644\n--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h\n+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h\n@@ -46,6 +46,11 @@ struct bpf_testmod_ops {\n \tstruct task_struct *(*test_return_ref_kptr)(int dummy, struct task_struct *task,\n \t\t\t\t\t\t    struct cgroup *cgrp);\n \n+\t/* Used to test indirect struct_ops trampoline with stack-passed arguments. */\n+\tint (*test_trampoline_stack_args)(int arg1, int arg2, int arg3,\n+\t\t\t\t\t  int arg4, int arg5, int arg6,\n+\t\t\t\t\t  int arg7, int arg8, int arg9);\n+\n \t/* The following fields are used to test shadow copies. */\n \tchar onebyte;\n \tstruct {\n"
}

core

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies files under tools/testing/selftests/ (BPF selftests and test_kmods), which are non-kernel selftests and do not affect the core kernel image (vmlinux) or production kernel modules. Therefore, fuzzing is not warranted.",
  "WorthFuzzing": false
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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


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

Target architecture: amd64

For your convenience, here is the diff of the changes:
commit d8463b0928ce9229d1d6885c0895e38eea283839
Author: syz-cluster <triage@syzkaller.com>
Date:   Tue Sep 8 08:00:51 2026 +0000

    syz-cluster: applied patch under review

diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_args.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_args.c
index 0f321e8898620..8767e5f8bcc72 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_args.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_args.c
@@ -3,7 +3,62 @@
 #include <test_progs.h>
 #include "struct_ops_multi_args.skel.h"
 
+static void test_refcounted_multi(void)
+{
+	struct struct_ops_multi_args *skel;
+	char log_buf[4096] = {};
+	int err;
+
+	skel = struct_ops_multi_args__open();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_multi_args__open"))
+		return;
+
+	bpf_program__set_log_buf(skel->progs.test_refcounted_multi, log_buf, sizeof(log_buf));
+
+	err = struct_ops_multi_args__load(skel);
+	if (!ASSERT_EQ(err, -EINVAL, "struct_ops_multi_args__load"))
+		goto out;
+
+	ASSERT_HAS_SUBSTR(log_buf, "program with __ref argument cannot tail call",
+			  "check_verifier_log_message");
+
+out:
+	struct_ops_multi_args__destroy(skel);
+}
+
+static void test_trampoline_stack_args(void)
+{
+	struct struct_ops_multi_args *skel;
+	struct bpf_link *link = NULL;
+	int err;
+
+	skel = struct_ops_multi_args__open();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_multi_args__open"))
+		return;
+
+	bpf_program__set_autoload(skel->progs.test_refcounted_multi, false);
+	skel->struct_ops.testmod_ref_acquire->test_refcounted_multi = NULL;
+
+	err = struct_ops_multi_args__load(skel);
+	if (!ASSERT_OK(err, "struct_ops_multi_args__load"))
+		goto out;
+
+	link = bpf_map__attach_struct_ops(skel->maps.testmod_ref_acquire);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops"))
+		goto out;
+
+	ASSERT_EQ(skel->bss->trampoline_stack_arg9, 9999, "check_stack_passed_arg9");
+
+out:
+	bpf_link__destroy(link);
+	struct_ops_multi_args__destroy(skel);
+}
+
 void test_struct_ops_multi_args(void)
 {
-	RUN_TESTS(struct_ops_multi_args);
+	if (test__start_subtest("test_refcounted_multi"))
+		test_refcounted_multi();
+
+	if (test__start_subtest("test_trampoline_stack_args"))
+		test_trampoline_stack_args();
 }
diff --git a/tools/testing/selftests/bpf/progs/struct_ops_multi_args.c b/tools/testing/selftests/bpf/progs/struct_ops_multi_args.c
index c62be15757f04..9d290f22b4926 100644
--- a/tools/testing/selftests/bpf/progs/struct_ops_multi_args.c
+++ b/tools/testing/selftests/bpf/progs/struct_ops_multi_args.c
@@ -17,7 +17,6 @@ struct {
 } prog_array SEC(".maps");
 
 SEC("struct_ops/test_refcounted_multi")
-__failure __msg("program with __ref argument cannot tail call")
 int test_refcounted_multi(unsigned long long *ctx)
 {
 	/* ctx[2] is used because the refcounted variable is the third argument */
@@ -29,7 +28,20 @@ int test_refcounted_multi(unsigned long long *ctx)
 	return 0;
 }
 
+__u64 trampoline_stack_arg9 = 0;
+
+SEC("struct_ops/test_trampoline_stack_args")
+int BPF_PROG(test_trampoline_stack_args, int arg1, int arg2, int arg3,
+					 int arg4, int arg5, int arg6,
+					 int arg7, int arg8, int arg9)
+{
+	trampoline_stack_arg9 = arg9;
+
+	return 0;
+}
+
 SEC(".struct_ops.link")
 struct bpf_testmod_ops testmod_ref_acquire = {
 	.test_refcounted_multi = (void *)test_refcounted_multi,
+	.test_trampoline_stack_args = (void *)test_trampoline_stack_args,
 };
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
index f798bbbb4d13c..df50b408972ac 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
@@ -1774,6 +1774,8 @@ static int bpf_dummy_reg(void *kdata, struct bpf_link *link)
 	 */
 	if (ops->test_2)
 		ops->test_2(4, ops->data);
+	if (ops->test_trampoline_stack_args)
+		ops->test_trampoline_stack_args(1, 2, 3, 4, 5, 6, 7, 8, 9999);
 
 	return 0;
 }
@@ -1821,6 +1823,13 @@ bpf_testmod_ops__test_return_ref_kptr(int dummy, struct task_struct *task__ref,
 	return NULL;
 }
 
+static int bpf_testmod_ops__test_trampoline_stack_args(int arg1, int arg2, int arg3,
+						       int arg4, int arg5, int arg6,
+						       int arg7, int arg8, int arg9)
+{
+	return arg9;
+}
+
 static struct bpf_testmod_ops __bpf_testmod_ops = {
 	.test_1 = bpf_testmod_test_1,
 	.test_2 = bpf_testmod_test_2,
@@ -1828,6 +1837,7 @@ static struct bpf_testmod_ops __bpf_testmod_ops = {
 	.test_refcounted = bpf_testmod_ops__test_refcounted,
 	.test_refcounted_multi = bpf_testmod_ops__test_refcounted_multi,
 	.test_return_ref_kptr = bpf_testmod_ops__test_return_ref_kptr,
+	.test_trampoline_stack_args = bpf_testmod_ops__test_trampoline_stack_args,
 };
 
 struct bpf_struct_ops bpf_bpf_testmod_ops = {
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h
index 210b919290cc2..2b12f81bf7487 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h
@@ -46,6 +46,11 @@ struct bpf_testmod_ops {
 	struct task_struct *(*test_return_ref_kptr)(int dummy, struct task_struct *task,
 						    struct cgroup *cgrp);
 
+	/* Used to test indirect struct_ops trampoline with stack-passed arguments. */
+	int (*test_trampoline_stack_args)(int arg1, int arg2, int arg3,
+					  int arg4, int arg5, int arg6,
+					  int arg7, int arg8, int arg9);
+
 	/* The following fields are used to test shadow copies. */
 	char onebyte;
 	struct {

gemini-3.7-flash

null

null

							input: 4973
							output: 91
							thoughts: 485
						

**WorthFuzzing Evaluation**

Okay, let's break this down. First, I need to analyze this patch diff. The modified files jump out at me: `tools/testing/selftests/bpf/prog_tests/test_struct_ops_multi_args.c`, `tools/testing/selftests/bpf/progs/struct_ops_multi_args.c`, `tools/testing/selftests/bpf/test_kmods/bpf_testmod.c`, and `tools/testing/selftests/bpf/test_kmods/bpf_testmod.h`. Notice that these are all self-tests, and specifically BPF tests, within the `tools/testing/selftests/` directory.

Just to be absolutely sure, I'll quickly double-check that this is the full list of modified files. Ah, confirmed. Only those four files. Now, let me consult those guidelines... Right, "Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories..." The negative criteria. One of those categories is, "User-space directories, self-tests... that do not affect the compiled kernel image (vmlinux) or kernel modules." Bingo! This clearly applies. These are BPF selftests.

Therefore, because all the changes are confined to `tools/testing/selftests/`, and specifically within the BPF selftests, I'm confident in setting `WorthFuzzing` to `false`. Consequently, both `FocusSymbols` and `EnableConfigs` are empty. I'll verify this now with the set-results command.

{
  "EnableConfigs": [],
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies files under tools/testing/selftests/ (BPF selftests and test_kmods), which are non-kernel selftests and do not affect the core kernel image (vmlinux) or production kernel modules. Therefore, fuzzing is not warranted.",
  "WorthFuzzing": false
}

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies files under tools/testing/selftests/ (BPF selftests and test_kmods), which are non-kernel selftests and do not affect the core kernel image (vmlinux) or production kernel modules. Therefore, fuzzing is not warranted.",
  "WorthFuzzing": false
}

{
  "WorthFuzzing": false
}

null