AI Trajectory

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies sample modules in samples/damon/. Sample modules are generally not fuzzed as they are just examples of API usage and not part of the core kernel or drivers.",
  "WorthFuzzing": false
}

null

{
  "PatchDiff": "commit 5c8f381ebf80661ad2d9eb9505d5046c7f9019fc\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Sun Jun 28 22:08:00 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/samples/damon/mtier.c b/samples/damon/mtier.c\nindex eb1143de8df17e..faaaaa12e6206b 100644\n--- a/samples/damon/mtier.c\n+++ b/samples/damon/mtier.c\n@@ -174,6 +174,7 @@ static struct damon_ctx *damon_sample_mtier_build_ctx(bool promote)\n static int damon_sample_mtier_start(void)\n {\n \tstruct damon_ctx *ctx;\n+\tint err;\n \n \tctx = damon_sample_mtier_build_ctx(true);\n \tif (!ctx)\n@@ -185,12 +186,21 @@ static int damon_sample_mtier_start(void)\n \t\treturn -ENOMEM;\n \t}\n \tctxs[1] = ctx;\n-\treturn damon_start(ctxs, 2, true);\n+\terr = damon_start(ctxs, 2, true);\n+\tif (!err)\n+\t\treturn 0;\n+\n+\tif (damon_is_running(ctxs[0]))\n+\t\tdamon_stop(ctxs, 1);\n+\tdamon_destroy_ctx(ctxs[0]);\n+\tdamon_destroy_ctx(ctxs[1]);\n+\treturn err;\n }\n \n static void damon_sample_mtier_stop(void)\n {\n-\tdamon_stop(ctxs, 2);\n+\tdamon_stop(ctxs, 1);\n+\tdamon_stop(\u0026ctxs[1], 1);\n \tdamon_destroy_ctx(ctxs[0]);\n \tdamon_destroy_ctx(ctxs[1]);\n }\ndiff --git a/samples/damon/prcl.c b/samples/damon/prcl.c\nindex b7c50f2656ce72..edeae145c4a8af 100644\n--- a/samples/damon/prcl.c\n+++ b/samples/damon/prcl.c\n@@ -106,11 +106,18 @@ static int damon_sample_prcl_start(void)\n \tdamon_set_schemes(ctx, \u0026scheme, 1);\n \n \terr = damon_start(\u0026ctx, 1, true);\n-\tif (err)\n+\tif (err) {\n+\t\tdamon_destroy_ctx(ctx);\n \t\treturn err;\n+\t}\n \n \trepeat_call_control.data = ctx;\n-\treturn damon_call(ctx, \u0026repeat_call_control);\n+\terr = damon_call(ctx, \u0026repeat_call_control);\n+\tif (err) {\n+\t\tdamon_stop(\u0026ctx, 1);\n+\t\tdamon_destroy_ctx(ctx);\n+\t}\n+\treturn err;\n }\n \n static void damon_sample_prcl_stop(void)\ndiff --git a/samples/damon/wsse.c b/samples/damon/wsse.c\nindex 799ad44439434a..ff5e8a890f448c 100644\n--- a/samples/damon/wsse.c\n+++ b/samples/damon/wsse.c\n@@ -87,10 +87,17 @@ static int damon_sample_wsse_start(void)\n \ttarget-\u003epid = target_pidp;\n \n \terr = damon_start(\u0026ctx, 1, true);\n-\tif (err)\n+\tif (err) {\n+\t\tdamon_destroy_ctx(ctx);\n \t\treturn err;\n+\t}\n \trepeat_call_control.data = ctx;\n-\treturn damon_call(ctx, \u0026repeat_call_control);\n+\terr = damon_call(ctx, \u0026repeat_call_control);\n+\tif (err) {\n+\t\tdamon_stop(\u0026ctx, 1);\n+\t\tdamon_destroy_ctx(ctx);\n+\t}\n+\treturn err;\n }\n \n static void damon_sample_wsse_stop(void)\n"
}

gemini-3.1-pro-preview

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies sample modules in samples/damon/. Sample modules are generally not fuzzed as they are just examples of API usage and not part of the core kernel or drivers.",
  "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 5c8f381ebf80661ad2d9eb9505d5046c7f9019fc
Author: syz-cluster <triage@syzkaller.com>
Date:   Sun Jun 28 22:08:00 2026 +0000

    syz-cluster: applied patch under review

diff --git a/samples/damon/mtier.c b/samples/damon/mtier.c
index eb1143de8df17e..faaaaa12e6206b 100644
--- a/samples/damon/mtier.c
+++ b/samples/damon/mtier.c
@@ -174,6 +174,7 @@ static struct damon_ctx *damon_sample_mtier_build_ctx(bool promote)
 static int damon_sample_mtier_start(void)
 {
 	struct damon_ctx *ctx;
+	int err;
 
 	ctx = damon_sample_mtier_build_ctx(true);
 	if (!ctx)
@@ -185,12 +186,21 @@ static int damon_sample_mtier_start(void)
 		return -ENOMEM;
 	}
 	ctxs[1] = ctx;
-	return damon_start(ctxs, 2, true);
+	err = damon_start(ctxs, 2, true);
+	if (!err)
+		return 0;
+
+	if (damon_is_running(ctxs[0]))
+		damon_stop(ctxs, 1);
+	damon_destroy_ctx(ctxs[0]);
+	damon_destroy_ctx(ctxs[1]);
+	return err;
 }
 
 static void damon_sample_mtier_stop(void)
 {
-	damon_stop(ctxs, 2);
+	damon_stop(ctxs, 1);
+	damon_stop(&ctxs[1], 1);
 	damon_destroy_ctx(ctxs[0]);
 	damon_destroy_ctx(ctxs[1]);
 }
diff --git a/samples/damon/prcl.c b/samples/damon/prcl.c
index b7c50f2656ce72..edeae145c4a8af 100644
--- a/samples/damon/prcl.c
+++ b/samples/damon/prcl.c
@@ -106,11 +106,18 @@ static int damon_sample_prcl_start(void)
 	damon_set_schemes(ctx, &scheme, 1);
 
 	err = damon_start(&ctx, 1, true);
-	if (err)
+	if (err) {
+		damon_destroy_ctx(ctx);
 		return err;
+	}
 
 	repeat_call_control.data = ctx;
-	return damon_call(ctx, &repeat_call_control);
+	err = damon_call(ctx, &repeat_call_control);
+	if (err) {
+		damon_stop(&ctx, 1);
+		damon_destroy_ctx(ctx);
+	}
+	return err;
 }
 
 static void damon_sample_prcl_stop(void)
diff --git a/samples/damon/wsse.c b/samples/damon/wsse.c
index 799ad44439434a..ff5e8a890f448c 100644
--- a/samples/damon/wsse.c
+++ b/samples/damon/wsse.c
@@ -87,10 +87,17 @@ static int damon_sample_wsse_start(void)
 	target->pid = target_pidp;
 
 	err = damon_start(&ctx, 1, true);
-	if (err)
+	if (err) {
+		damon_destroy_ctx(ctx);
 		return err;
+	}
 	repeat_call_control.data = ctx;
-	return damon_call(ctx, &repeat_call_control);
+	err = damon_call(ctx, &repeat_call_control);
+	if (err) {
+		damon_stop(&ctx, 1);
+		damon_destroy_ctx(ctx);
+	}
+	return err;
 }
 
 static void damon_sample_wsse_stop(void)

gemini-3.1-pro-preview

null

null

							input: 2679
							output: 23
							thoughts: 129
						

**DAMON Sample Module Review**

Okay, so this patch is touching `samples/damon/mtier.c`, `samples/damon/prcl.c`, and `samples/damon/wsse.c`. Right, these are the sample modules related to DAMON – Data Access MONitor. My initial thought is, as usual with samples, we probably don't need to dive too deep into fuzzing them *unless* they expose some kind of external interface. They're primarily meant to be illustrative examples.

Before I jump to any conclusions, let's confirm they're even compiled and linked in the build. It would be a waste of time to look at fuzzing something that’s not even part of the kernel image. The standard practice for this level is to avoid fuzzing code under the `samples/` directory with syzkaller, but I want to make sure. I'll need to check the Kconfig files, either `samples/damon/Kconfig` or the global `samples/Kconfig` to see the build configuration and what's enabled. That'll tell us if we have something actionable here.

{
  "Expression": "damon_sample_mtier_start"
}

{
  "Output": "samples/damon/mtier.c=73=static struct damon_ctx *damon_sample_mtier_build_ctx(bool promote)\n--\nsamples/damon/mtier.c-173-\nsamples/damon/mtier.c:174:static int damon_sample_mtier_start(void)\nsamples/damon/mtier.c-175-{\n--\nsamples/damon/mtier.c=208=static int damon_sample_mtier_enable_store(\n--\nsamples/damon/mtier.c-224-\tif (enabled) {\nsamples/damon/mtier.c:225:\t\terr = damon_sample_mtier_start();\nsamples/damon/mtier.c-226-\t\tif (err)\n--\nsamples/damon/mtier.c=234=static int __init damon_sample_mtier_init(void)\n--\nsamples/damon/mtier.c-244-\tif (enabled) {\nsamples/damon/mtier.c:245:\t\terr = damon_sample_mtier_start();\nsamples/damon/mtier.c-246-\t\tif (err)\n"
}

gemini-3.1-pro-preview

null

null

							input: 3389
							output: 32
							thoughts: 78
						

**Kernel Module Fuzzing Considerations**

Okay, so I'm looking at these kernel modules, and they're sitting in the `samples/` directory. My initial instinct, given my experience, is that `samples/` code is often illustrative, not necessarily production-ready, and usually isn't the first place I'd target for fuzzing. However, that doesn't mean we should dismiss them entirely. We need to be thorough.

The key question is whether these modules are actually *reachable* from user space. If they are, then they become a potential attack surface, even if they're in `samples/`. A quick check for this is in order.

Aha, and it looks like they have module parameters, namely `enable_store`. This is promising – parameters often provide a crucial entry point for interacting with kernel modules from userland, and therefore, for fuzzing. 

To dig deeper, let's take a look at `samples/damon/mtier.c` as an example to see how they're used. This should give us a clearer picture of how these samples function and whether they warrant more in-depth fuzzing efforts.

{
  "Expression": "module_param",
  "PathPrefix": "samples/damon/mtier.c"
}

{
  "Output": "samples/damon/mtier.c=20=static unsigned long node0_start_addr __read_mostly;\nsamples/damon/mtier.c:21:module_param(node0_start_addr, ulong, 0600);\nsamples/damon/mtier.c-22-\nsamples/damon/mtier.c=23=static unsigned long node0_end_addr __read_mostly;\nsamples/damon/mtier.c:24:module_param(node0_end_addr, ulong, 0600);\nsamples/damon/mtier.c-25-\nsamples/damon/mtier.c=26=static unsigned long node1_start_addr __read_mostly;\nsamples/damon/mtier.c:27:module_param(node1_start_addr, ulong, 0600);\nsamples/damon/mtier.c-28-\nsamples/damon/mtier.c=29=static unsigned long node1_end_addr __read_mostly;\nsamples/damon/mtier.c:30:module_param(node1_end_addr, ulong, 0600);\nsamples/damon/mtier.c-31-\nsamples/damon/mtier.c=32=static unsigned long node0_mem_used_bp __read_mostly = 9970;\nsamples/damon/mtier.c:33:module_param(node0_mem_used_bp, ulong, 0600);\nsamples/damon/mtier.c-34-\nsamples/damon/mtier.c=35=static unsigned long node0_mem_free_bp __read_mostly = 50;\nsamples/damon/mtier.c:36:module_param(node0_mem_free_bp, ulong, 0600);\nsamples/damon/mtier.c-37-\n--\nsamples/damon/mtier.c=46=static bool enabled __read_mostly;\nsamples/damon/mtier.c:47:module_param_cb(enabled, \u0026enabled_param_ops, \u0026enabled, 0600);\nsamples/damon/mtier.c-48-MODULE_PARM_DESC(enabled, \"Enable or disable DAMON_SAMPLE_MTIER\");\n--\nsamples/damon/mtier.c=50=static bool detect_node_addresses __read_mostly;\nsamples/damon/mtier.c:51:module_param(detect_node_addresses, bool, 0600);\nsamples/damon/mtier.c-52-\n"
}

gemini-3.1-pro-preview

null

null

							input: 4404
							output: 69
							thoughts: 39
						

**My Assessment of These Modules**

Okay, so these modules are just sample code, examples really. It's clear that Syzkaller isn't designed to actually fuzz *these* specific examples. They're here to demonstrate how to effectively interact with the DAMON API, nothing more. My primary goal here is to determine whether a target is suitable for fuzzing. Given this context, I'm going to set `WorthFuzzing=false`. These modules, in their current form, simply don't warrant the effort.

{
  "EnableConfigs": [],
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies sample modules in samples/damon/. Sample modules are generally not fuzzed as they are just examples of API usage and not part of the core kernel or drivers.",
  "WorthFuzzing": false
}

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies sample modules in samples/damon/. Sample modules are generally not fuzzed as they are just examples of API usage and not part of the core kernel or drivers.",
  "WorthFuzzing": false
}