AI Trajectory


Trajectory: (Expand/Collapse All)
Seq Timestamp Type Name Duration
0/0 2026/06/24 15:34 flow patch-triage
0m Args: 
null

Results: 
{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only introduces a safe Rust wrapper for `synchronize_rcu()` and replaces existing unsafe FFI calls with this new wrapper. It does not change any functional logic or execution flow.",
  "WorthFuzzing": false
}
1/1 2026/06/24 15:34 action read-patch-diff
0m Args: 
null

Results: 
{
  "PatchDiff": "commit 5d548e2985bcba98c693658a34f9f2bb95de40c8\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Wed Jun 24 15:34:15 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/rust/kernel/revocable.rs b/rust/kernel/revocable.rs\nindex 0f4ae673256d56..f539603349f1cb 100644\n--- a/rust/kernel/revocable.rs\n+++ b/rust/kernel/revocable.rs\n@@ -7,7 +7,11 @@\n \n use pin_init::Wrapper;\n \n-use crate::{bindings, prelude::*, sync::rcu, types::Opaque};\n+use crate::{\n+    prelude::*,\n+    sync::rcu,\n+    types::Opaque, //\n+};\n use core::{\n     marker::PhantomData,\n     ops::Deref,\n@@ -161,8 +165,7 @@ unsafe fn revoke_internal\u003cconst SYNC: bool\u003e(\u0026self) -\u003e bool {\n \n         if revoke {\n             if SYNC {\n-                // SAFETY: Just an FFI call, there are no further requirements.\n-                unsafe { bindings::synchronize_rcu() };\n+                rcu::synchronize_rcu();\n             }\n \n             // SAFETY: We know `self.data` is valid because only one CPU can succeed the\ndiff --git a/rust/kernel/sync/poll.rs b/rust/kernel/sync/poll.rs\nindex 0ec985d560c8d3..30ebeea1702f99 100644\n--- a/rust/kernel/sync/poll.rs\n+++ b/rust/kernel/sync/poll.rs\n@@ -8,7 +8,11 @@\n     bindings,\n     fs::File,\n     prelude::*,\n-    sync::{CondVar, LockClassKey},\n+    sync::{\n+        CondVar,\n+        LockClassKey,\n+        rcu::synchronize_rcu, //\n+    }, //\n };\n use core::{marker::PhantomData, ops::Deref};\n \n@@ -99,8 +103,6 @@ fn drop(self: Pin\u003c\u0026mut Self\u003e) {\n         unsafe { bindings::__wake_up_pollfree(self.inner.wait_queue_head.get()) };\n \n         // Wait for epoll items to be properly removed.\n-        //\n-        // SAFETY: Just an FFI call.\n-        unsafe { bindings::synchronize_rcu() };\n+        synchronize_rcu();\n     }\n }\ndiff --git a/rust/kernel/sync/rcu.rs b/rust/kernel/sync/rcu.rs\nindex a32bef6e490b0e..2bae76d229f09d 100644\n--- a/rust/kernel/sync/rcu.rs\n+++ b/rust/kernel/sync/rcu.rs\n@@ -50,3 +50,19 @@ fn drop(\u0026mut self) {\n pub fn read_lock() -\u003e Guard {\n     Guard::new()\n }\n+\n+/// Wait for one RCU grace period.\n+///\n+/// Waits for all RCU read-side critical sections (such as those established by\n+/// a [`rcu::Guard`]) at the moment of the function call to finish.\n+///\n+/// Does not prevent new read-side critical sections from starting, which may\n+/// begin and run while this call is blocking.\n+///\n+/// Note that this is one of the RCU primitives which must not be called in\n+/// atomic context.\n+#[inline]\n+pub fn synchronize_rcu() {\n+    // SAFETY: `synchronize_rcu()` is always safe to be called from process context.\n+    unsafe { bindings::synchronize_rcu() };\n+}\n"
}
2/1 2026/06/24 15:34 agent patch-evaluator
0m Model: 
gemini-3.1-pro-preview

Args: 
null

Results: 
{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only introduces a safe Rust wrapper for `synchronize_rcu()` and replaces existing unsafe FFI calls with this new wrapper. It does not change any functional logic or execution flow.",
  "WorthFuzzing": false
}

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).

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.

Prompt: 
For your convenience, here is the diff of the changes:
commit 5d548e2985bcba98c693658a34f9f2bb95de40c8
Author: syz-cluster <triage@syzkaller.com>
Date:   Wed Jun 24 15:34:15 2026 +0000

    syz-cluster: applied patch under review

diff --git a/rust/kernel/revocable.rs b/rust/kernel/revocable.rs
index 0f4ae673256d56..f539603349f1cb 100644
--- a/rust/kernel/revocable.rs
+++ b/rust/kernel/revocable.rs
@@ -7,7 +7,11 @@
 
 use pin_init::Wrapper;
 
-use crate::{bindings, prelude::*, sync::rcu, types::Opaque};
+use crate::{
+    prelude::*,
+    sync::rcu,
+    types::Opaque, //
+};
 use core::{
     marker::PhantomData,
     ops::Deref,
@@ -161,8 +165,7 @@ unsafe fn revoke_internal<const SYNC: bool>(&self) -> bool {
 
         if revoke {
             if SYNC {
-                // SAFETY: Just an FFI call, there are no further requirements.
-                unsafe { bindings::synchronize_rcu() };
+                rcu::synchronize_rcu();
             }
 
             // SAFETY: We know `self.data` is valid because only one CPU can succeed the
diff --git a/rust/kernel/sync/poll.rs b/rust/kernel/sync/poll.rs
index 0ec985d560c8d3..30ebeea1702f99 100644
--- a/rust/kernel/sync/poll.rs
+++ b/rust/kernel/sync/poll.rs
@@ -8,7 +8,11 @@
     bindings,
     fs::File,
     prelude::*,
-    sync::{CondVar, LockClassKey},
+    sync::{
+        CondVar,
+        LockClassKey,
+        rcu::synchronize_rcu, //
+    }, //
 };
 use core::{marker::PhantomData, ops::Deref};
 
@@ -99,8 +103,6 @@ fn drop(self: Pin<&mut Self>) {
         unsafe { bindings::__wake_up_pollfree(self.inner.wait_queue_head.get()) };
 
         // Wait for epoll items to be properly removed.
-        //
-        // SAFETY: Just an FFI call.
-        unsafe { bindings::synchronize_rcu() };
+        synchronize_rcu();
     }
 }
diff --git a/rust/kernel/sync/rcu.rs b/rust/kernel/sync/rcu.rs
index a32bef6e490b0e..2bae76d229f09d 100644
--- a/rust/kernel/sync/rcu.rs
+++ b/rust/kernel/sync/rcu.rs
@@ -50,3 +50,19 @@ fn drop(&mut self) {
 pub fn read_lock() -> Guard {
     Guard::new()
 }
+
+/// Wait for one RCU grace period.
+///
+/// Waits for all RCU read-side critical sections (such as those established by
+/// a [`rcu::Guard`]) at the moment of the function call to finish.
+///
+/// Does not prevent new read-side critical sections from starting, which may
+/// begin and run while this call is blocking.
+///
+/// Note that this is one of the RCU primitives which must not be called in
+/// atomic context.
+#[inline]
+pub fn synchronize_rcu() {
+    // SAFETY: `synchronize_rcu()` is always safe to be called from process context.
+    unsafe { bindings::synchronize_rcu() };
+}

3/2 2026/06/24 15:34 llm patch-evaluator
0m Model: 
gemini-3.1-pro-preview

Args: 
null

Results: 
null

Tokens: 
							input: 2512
							output: 70
							thoughts: 441

Thoughts: 
**RCU Synchronization Wrapper: A Safety-Oriented Refactoring**

Okay, so I'm looking at this patch modifying Rust code within the Linux kernel, specifically touching `rust/kernel/revocable.rs`, `rust/kernel/sync/poll.rs`, and `rust/kernel/sync/rcu.rs`. It's pretty straightforward: the core of it is a safe wrapper for `synchronize_rcu()` in `rust/kernel/sync/rcu.rs`. The goal here is clear – replacing those direct FFI calls to `bindings::synchronize_rcu()` with our new, safer `rcu::synchronize_rcu()` wrapper within `revocable.rs` and `poll.rs`.

Let's quickly go through it to make sure I'm on the right track.

The `rust/kernel/sync/rcu.rs` change simply adds:

```rust
+#[inline]
+pub fn synchronize_rcu() {
+    // SAFETY: `synchronize_rcu()` is always safe to be called from process context.
+    unsafe { bindings::synchronize_rcu() };
+}
```

And in `rust/kernel/revocable.rs` and `rust/kernel/sync/poll.rs`, we get:

```rust
-                unsafe { bindings::synchronize_rcu() };
+                rcu::synchronize_rcu();
```
and
```rust
-        unsafe { bindings::synchronize_rcu() };
+        synchronize_rcu();
```

Essentially, this is a clean refactoring. It's not changing the fundamental execution path, it's just replacing direct, potentially error-prone FFI calls with a controlled wrapper that does the *exact* same thing. The inline attribute ensures that the wrapper is elided during compilation so no performance change occurs. Thus, the compiled output remains identical.

Given this, I don't see any value in fuzzing this patch. It's a safety improvement and refactoring; it doesn't introduce any new logic or behavior that would be susceptible to fuzzing-based vulnerability discovery. I'm going to set `WorthFuzzing: false`.

4/2 2026/06/24 15:34 tool set-results
0m Args: 
{
  "EnableConfigs": [],
  "FocusSymbols": [],
  "Reasoning": "The patch only introduces a safe Rust wrapper for `synchronize_rcu()` and replaces existing unsafe FFI calls with this new wrapper. It does not change any functional logic or execution flow.",
  "WorthFuzzing": false
}

Results: 
{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only introduces a safe Rust wrapper for `synchronize_rcu()` and replaces existing unsafe FFI calls with this new wrapper. It does not change any functional logic or execution flow.",
  "WorthFuzzing": false
}
LLM Calls Summary:
Total Calls Total Tokens Avg Tokens Total Duration (Seconds) Avg Duration (Seconds)
Tool Calls Summary:
Total Calls Total Duration (Seconds) Avg Duration (Seconds)