AI Trajectory

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch replaces cond_resched() with cond_resched_tasks_rcu_qs() in kmemleak scanning functions to prevent RCU stall warnings. This is a minor scheduling/RCU change that does not introduce new functional logic or features that require fuzzing.",
  "WorthFuzzing": false
}

null

{
  "PatchDiff": "commit 39480d407f010919b3b5475a5cefd9ffd21b7552\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Mon Jul 20 18:00:13 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/mm/kmemleak.c b/mm/kmemleak.c\nindex 85f18b17e79c4e..f63dfacee7ca10 100644\n--- a/mm/kmemleak.c\n+++ b/mm/kmemleak.c\n@@ -1586,7 +1586,7 @@ static int scan_large_block(void *start, void *end)\n \t\tif (scan_block(start, next, NULL))\n \t\t\treturn 1;\n \t\tstart = next;\n-\t\tcond_resched();\n+\t\tcond_resched_tasks_rcu_qs();\n \t}\n \n \treturn 0;\n@@ -1623,7 +1623,7 @@ static void scan_object(struct kmemleak_object *object)\n \t\t\tscan_block(start, end, object);\n \n \t\t\traw_spin_unlock_irqrestore(\u0026object-\u003elock, flags);\n-\t\t\tcond_resched();\n+\t\t\tcond_resched_tasks_rcu_qs();\n \t\t\traw_spin_lock_irqsave(\u0026object-\u003elock, flags);\n \t\t\tif (!(object-\u003eflags \u0026 OBJECT_ALLOCATED))\n \t\t\t\tbreak;\n@@ -1645,7 +1645,7 @@ static void scan_object(struct kmemleak_object *object)\n \t\t\t\tbreak;\n \n \t\t\traw_spin_unlock_irqrestore(\u0026object-\u003elock, flags);\n-\t\t\tcond_resched();\n+\t\t\tcond_resched_tasks_rcu_qs();\n \t\t\traw_spin_lock_irqsave(\u0026object-\u003elock, flags);\n \t\t} while (object-\u003eflags \u0026 OBJECT_ALLOCATED);\n \t} else {\n@@ -1673,7 +1673,7 @@ static void scan_gray_list(void)\n \t */\n \tobject = list_entry(gray_list.next, typeof(*object), gray_list);\n \twhile (\u0026object-\u003egray_list != \u0026gray_list) {\n-\t\tcond_resched();\n+\t\tcond_resched_tasks_rcu_qs();\n \n \t\t/* may add new objects to the list */\n \t\tif (!scan_should_stop())\n@@ -1708,7 +1708,7 @@ static void kmemleak_cond_resched(struct kmemleak_object *object)\n \traw_spin_unlock_irq(\u0026kmemleak_lock);\n \n \trcu_read_unlock();\n-\tcond_resched();\n+\tcond_resched_tasks_rcu_qs();\n \trcu_read_lock();\n \n \traw_spin_lock_irq(\u0026kmemleak_lock);\n@@ -1753,7 +1753,7 @@ static void kmemleak_scan_task_stacks(void)\n \t\t\t}\n \t\t\tput_task_struct(p);\n \t\t}\n-\t\tcond_resched();\n+\t\tcond_resched_tasks_rcu_qs();\n \t} while (pid \u0026\u0026 !stop);\n }\n \n@@ -1935,7 +1935,7 @@ static int __kmemleak_scan(bool full)\n \t\t\tstruct page *page = pfn_to_online_page(pfn);\n \n \t\t\tif (!(pfn \u0026 63))\n-\t\t\t\tcond_resched();\n+\t\t\t\tcond_resched_tasks_rcu_qs();\n \n \t\t\tif (!page)\n \t\t\t\tcontinue;\n"
}

best-expensive

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch replaces cond_resched() with cond_resched_tasks_rcu_qs() in kmemleak scanning functions to prevent RCU stall warnings. This is a minor scheduling/RCU change that does not introduce new functional logic or features that require fuzzing.",
  "WorthFuzzing": false
}

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).

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.
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.
   Do not list too generic configs (we already have them enabled). Only list those that
   specifically cover the modified code. 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.

For your convenience, here is the diff of the changes:
commit 39480d407f010919b3b5475a5cefd9ffd21b7552
Author: syz-cluster <triage@syzkaller.com>
Date:   Mon Jul 20 18:00:13 2026 +0000

    syz-cluster: applied patch under review

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 85f18b17e79c4e..f63dfacee7ca10 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1586,7 +1586,7 @@ static int scan_large_block(void *start, void *end)
 		if (scan_block(start, next, NULL))
 			return 1;
 		start = next;
-		cond_resched();
+		cond_resched_tasks_rcu_qs();
 	}
 
 	return 0;
@@ -1623,7 +1623,7 @@ static void scan_object(struct kmemleak_object *object)
 			scan_block(start, end, object);
 
 			raw_spin_unlock_irqrestore(&object->lock, flags);
-			cond_resched();
+			cond_resched_tasks_rcu_qs();
 			raw_spin_lock_irqsave(&object->lock, flags);
 			if (!(object->flags & OBJECT_ALLOCATED))
 				break;
@@ -1645,7 +1645,7 @@ static void scan_object(struct kmemleak_object *object)
 				break;
 
 			raw_spin_unlock_irqrestore(&object->lock, flags);
-			cond_resched();
+			cond_resched_tasks_rcu_qs();
 			raw_spin_lock_irqsave(&object->lock, flags);
 		} while (object->flags & OBJECT_ALLOCATED);
 	} else {
@@ -1673,7 +1673,7 @@ static void scan_gray_list(void)
 	 */
 	object = list_entry(gray_list.next, typeof(*object), gray_list);
 	while (&object->gray_list != &gray_list) {
-		cond_resched();
+		cond_resched_tasks_rcu_qs();
 
 		/* may add new objects to the list */
 		if (!scan_should_stop())
@@ -1708,7 +1708,7 @@ static void kmemleak_cond_resched(struct kmemleak_object *object)
 	raw_spin_unlock_irq(&kmemleak_lock);
 
 	rcu_read_unlock();
-	cond_resched();
+	cond_resched_tasks_rcu_qs();
 	rcu_read_lock();
 
 	raw_spin_lock_irq(&kmemleak_lock);
@@ -1753,7 +1753,7 @@ static void kmemleak_scan_task_stacks(void)
 			}
 			put_task_struct(p);
 		}
-		cond_resched();
+		cond_resched_tasks_rcu_qs();
 	} while (pid && !stop);
 }
 
@@ -1935,7 +1935,7 @@ static int __kmemleak_scan(bool full)
 			struct page *page = pfn_to_online_page(pfn);
 
 			if (!(pfn & 63))
-				cond_resched();
+				cond_resched_tasks_rcu_qs();
 
 			if (!page)
 				continue;

gemini-3.1-pro-preview

null

null

							input: 2539
							output: 88
							thoughts: 374
						

**Kmemleak Patch Analysis: Worth Fuzzing?**

Okay, so this patch in `mm/kmemleak.c` is switching out `cond_resched()` for `cond_resched_tasks_rcu_qs()`. Seems like a straightforward, minor tweak related to scheduling and RCU during kmemleak scans. The initial impression is that it doesn't touch the core logic or introduce anything novel that would scream "FUZZ ME!"

Wait a minute, though. Does this *actually* alter behavior? Aha! It *does*. It's calling the new function, which includes `cond_resched()` but *also* incorporates quiescent state reporting for RCU. Hmm, a bug fix for RCU stalls during kmemleak scans, not a new feature.

The question then becomes: is it worth the effort to fuzz this specific change? My gut says no. The primary goal here is to prevent those annoying RCU stall warnings during kmemleak scanning. Fuzzing this *specifically* isn't going to unearth any new bugs in kmemleak's fundamental functionality. It's more of a refinement to prevent a specific type of warning.

Just to be absolutely certain, let me take a quick look at `cond_resched_tasks_rcu_qs()` itself. Yep, just a scheduling/RCU adjustment.

Therefore, after a closer look, I am going to set `WorthFuzzing=false`. It's a non-functional improvement, essentially a housekeeping change to sidestep potential RCU stall issues. It doesn't introduce any new functional areas that demand fuzzing.

Just to double-check I'll look at the file changes. Okay, it's just the replacement of `cond_resched()` with `cond_resched_tasks_rcu_qs()` in a number of kmemleak functions like `scan_large_block`, `scan_object`, `scan_gray_list`, `kmemleak_cond_resched`, `kmemleak_scan_task_stacks`, and `__kmemleak_scan`.

Purely non-functional. `WorthFuzzing=false` it is.

{
  "EnableConfigs": [],
  "FocusSymbols": [],
  "Reasoning": "The patch replaces cond_resched() with cond_resched_tasks_rcu_qs() in kmemleak scanning functions to prevent RCU stall warnings. This is a minor scheduling/RCU change that does not introduce new functional logic or features that require fuzzing.",
  "WorthFuzzing": false
}

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch replaces cond_resched() with cond_resched_tasks_rcu_qs() in kmemleak scanning functions to prevent RCU stall warnings. This is a minor scheduling/RCU change that does not introduce new functional logic or features that require fuzzing.",
  "WorthFuzzing": false
}