AI Trajectory

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only adds a new exported function `neigh_parms_lookup_dev` which is currently unused anywhere in the kernel tree. Since it has no callers, it is unreachable and cannot be fuzzed.",
  "WorthFuzzing": false
}

null

{
  "PatchDiff": "commit 19d33101c95ad9e01247373bfdd8cf236045ab8a\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Mon Jun 29 16:56:16 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/include/net/neighbour.h b/include/net/neighbour.h\nindex 8860cc2175fc1c..1b3b06eda8865c 100644\n--- a/include/net/neighbour.h\n+++ b/include/net/neighbour.h\n@@ -438,6 +438,8 @@ int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,\n \t\t\t  proc_handler *proc_handler);\n void neigh_sysctl_unregister(struct neigh_parms *p);\n \n+struct neigh_parms *neigh_parms_lookup_dev(struct neigh_table *tbl, struct net_device *dev);\n+\n static inline void __neigh_parms_put(struct neigh_parms *parms)\n {\n \trefcount_dec(\u0026parms-\u003erefcnt);\ndiff --git a/net/core/neighbour.c b/net/core/neighbour.c\nindex 1349c0eedb6425..6d32c2668af383 100644\n--- a/net/core/neighbour.c\n+++ b/net/core/neighbour.c\n@@ -1757,6 +1757,14 @@ static inline struct neigh_parms *lookup_neigh_parms(struct neigh_table *tbl,\n \treturn NULL;\n }\n \n+/* Caller must hold rcu_read_lock()*/\n+\n+struct neigh_parms *neigh_parms_lookup_dev(struct neigh_table *tbl, struct net_device *dev)\n+{\n+\treturn lookup_neigh_parms(tbl, dev_net(dev), dev-\u003eifindex);\n+}\n+EXPORT_SYMBOL(neigh_parms_lookup_dev);\n+\n struct neigh_parms *neigh_parms_alloc(struct net_device *dev,\n \t\t\t\t      struct neigh_table *tbl)\n {\n"
}

gemini-3.1-pro-preview

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only adds a new exported function `neigh_parms_lookup_dev` which is currently unused anywhere in the kernel tree. Since it has no callers, it is unreachable and cannot be fuzzed.",
  "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 19d33101c95ad9e01247373bfdd8cf236045ab8a
Author: syz-cluster <triage@syzkaller.com>
Date:   Mon Jun 29 16:56:16 2026 +0000

    syz-cluster: applied patch under review

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 8860cc2175fc1c..1b3b06eda8865c 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -438,6 +438,8 @@ int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 			  proc_handler *proc_handler);
 void neigh_sysctl_unregister(struct neigh_parms *p);
 
+struct neigh_parms *neigh_parms_lookup_dev(struct neigh_table *tbl, struct net_device *dev);
+
 static inline void __neigh_parms_put(struct neigh_parms *parms)
 {
 	refcount_dec(&parms->refcnt);
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 1349c0eedb6425..6d32c2668af383 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1757,6 +1757,14 @@ static inline struct neigh_parms *lookup_neigh_parms(struct neigh_table *tbl,
 	return NULL;
 }
 
+/* Caller must hold rcu_read_lock()*/
+
+struct neigh_parms *neigh_parms_lookup_dev(struct neigh_table *tbl, struct net_device *dev)
+{
+	return lookup_neigh_parms(tbl, dev_net(dev), dev->ifindex);
+}
+EXPORT_SYMBOL(neigh_parms_lookup_dev);
+
 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 				      struct neigh_table *tbl)
 {

gemini-3.1-pro-preview

null

null

							input: 2097
							output: 22
							thoughts: 122
						

**New Function: neigh_parms_lookup_dev**

Okay, so there's a new patch, and it looks like it introduces a new, exported function called `neigh_parms_lookup_dev`. It's defined in `net/core/neighbour.c` and declared in `include/net/neighbour.h`. The function itself seems to be a wrapper around `lookup_neigh_parms`. Hmm, interesting.

My first thought is always, "Where is this used?" If this is a standalone addition, and it's *not* currently being utilized by anything in the kernel, then it might not be a high priority for immediate fuzzing. It could be dead code, or perhaps part of a larger, still-in-progress patch series. The documentation only mentions the addition of the function. Let's start with a search through the kernel codebase to see if `neigh_parms_lookup_dev` is actually called anywhere. That will dictate where to go next.

{
  "Expression": "neigh_parms_lookup_dev"
}

{
  "Output": "include/net/neighbour.h=439=void neigh_sysctl_unregister(struct neigh_parms *p);\ninclude/net/neighbour.h-440-\ninclude/net/neighbour.h:441:struct neigh_parms *neigh_parms_lookup_dev(struct neigh_table *tbl, struct net_device *dev);\ninclude/net/neighbour.h-442-\n--\nnet/core/neighbour.c=1746=static inline struct neigh_parms *lookup_neigh_parms(struct neigh_table *tbl,\n--\nnet/core/neighbour.c-1761-\nnet/core/neighbour.c:1762:struct neigh_parms *neigh_parms_lookup_dev(struct neigh_table *tbl, struct net_device *dev)\nnet/core/neighbour.c-1763-{\n--\nnet/core/neighbour.c-1765-}\nnet/core/neighbour.c:1766:EXPORT_SYMBOL(neigh_parms_lookup_dev);\nnet/core/neighbour.c-1767-\n"
}

gemini-3.1-pro-preview

null

null

							input: 2729
							output: 75
							thoughts: 291
						

**Unused Function - WorthFuzzing=False**

Okay, so I'm looking at this `neigh_parms_lookup_dev` function. The first thing that jumps out is that it's just being added and exported, but it doesn't seem to be used anywhere within the provided patch. I need to make sure I'm not missing something; perhaps another patch in the series calls it? But the description says it's only one commit.

I've checked the grepper output, which only shows the declaration and the definition within `include/net/neighbour.h` and `net/core/neighbour.c` respectively. Therefore, this function is *definitely* not being called anywhere within the codebase that *I* have access to.

So, the question is, is this worth fuzzing? Honestly, no. If the function is never called, then it's unreachable, period. Fuzzing it would be a waste of resources unless it is called somewhere that *I* do not have access to. It could be called by an out-of-tree module, but I'm only reviewing this single patch.

Hang on... could this be a fix for something that *already* exists under a different name? No, this patch is *adding* the function, not changing a caller. Also, there are no other changes in this commit besides the addition of `neigh_parms_lookup_dev`.

Alright, I'm confident. I'm going to set `WorthFuzzing=false`.

{
  "EnableConfigs": [],
  "FocusSymbols": [],
  "Reasoning": "The patch only adds a new exported function `neigh_parms_lookup_dev` which is currently unused anywhere in the kernel tree. Since it has no callers, it is unreachable and cannot be fuzzed.",
  "WorthFuzzing": false
}

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only adds a new exported function `neigh_parms_lookup_dev` which is currently unused anywhere in the kernel tree. Since it has no callers, it is unreachable and cannot be fuzzed.",
  "WorthFuzzing": false
}