AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/08/12 08:26	flow	patch-triage	0m Args: null Results: { "EnableConfigs": null, "FocusSymbols": [], "KMSANReasoning": "", "NeedsKMSAN": false, "Reasoning": "The patch only modifies Documentation files (ABI and admin-guide) and does not contain any functional code changes.", "WorthFuzzing": false }
1/1	2026/08/12 08:26	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit 8946b90004708bfb398a9e7a7511aa50289fd0d2\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Wed Aug 12 08:26:44 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage\nindex 7bfbb9cc2c113..bbdfae2c0caa6 100644\n--- a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage\n+++ b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage\n@@ -10,9 +10,19 @@ Description:\n \t\t\t- hpage_pmd_size\n \t\t\t- khugepaged\n \t\t\t- shmem_enabled\n+\t\t\t- shrink_underused\n \t\t\t- use_zero_page\n \t\t\t- subdirectories of the form hugepages-\u003csize\u003ekB, where \u003csize\u003e\n \t\t\t is the page size of the hugepages supported by the kernel/CPU\n \t\t\t combination.\n \n \t\tSee Documentation/admin-guide/mm/transhuge.rst for details.\n+\n+What:\t\t/sys/kernel/mm/transparent_hugepage/shrink_underused\n+Date:\t\tSep 2024\n+Contact:\tLinux memory management mailing list \u003clinux-mm@kvack.org\u003e\n+Description:\tReading and writing this file controls whether khugepaged\n+\t\tsplits underused transparent huge pages (THPs) under memory\n+\t\tpressure. A THP is considered underused when its number of\n+\t\tzero-filled pages is above max_ptes_none. Enabled by default;\n+\t\twriting 0 disables the splitting and 1 enables it.\ndiff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst\nindex b187d618452f4..72e944f49da5b 100644\n--- a/Documentation/admin-guide/mm/transhuge.rst\n+++ b/Documentation/admin-guide/mm/transhuge.rst\n@@ -389,14 +389,14 @@ is not defined within a valid ``thp_anon``, its policy will default to\n Similarly to ``transparent_hugepage``, you can control the hugepage\n allocation policy for the internal shmem mount by using the kernel parameter\n ``transparent_hugepage_shmem=\u003cpolicy\u003e``, where ``\u003cpolicy\u003e`` is one of the\n-seven valid policies for shmem (``always``, ``within_size``, ``advise``,\n+six valid policies for shmem (``always``, ``within_size``, ``advise``,\n ``never``, ``deny``, and ``force``).\n \n Similarly to ``transparent_hugepage_shmem``, you can control the default\n hugepage allocation policy for the tmpfs mount by using the kernel parameter\n ``transparent_hugepage_tmpfs=\u003cpolicy\u003e``, where ``\u003cpolicy\u003e`` is one of the\n-four valid policies for tmpfs (``always``, ``within_size``, ``advise``,\n-``never``). The tmpfs mount default policy is ``never``.\n+six valid policies for tmpfs (``always``, ``within_size``, ``advise``,\n+``never``, ``deny``, and ``force``). The tmpfs mount default policy is ``never``.\n \n Additionally, Kconfig options are available to set the default hugepage\n policies for shmem (``CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_*``) and tmpfs\n" }
2/1	2026/08/12 08:26	agent	patch-evaluator	0m Model: best-expensive Args: null Results: { "EnableConfigs": null, "FocusSymbols": [], "Reasoning": "The patch only modifies Documentation files (ABI and admin-guide) and does not contain any functional code changes.", "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). - Code in vendor-specific PCIe switch, SmartNIC, or GPU drivers (e.g., mlxsw, pds_core, qed, ionic, amdgpu) that require physical PCIe hardware cards not emulated in standard QEMU. - Driver .remove, .shutdown, or pci_unregister_driver teardown callbacks (e.g., igb_remove) that are executed only during PCI hot-unplug or sysfs driver unbind operations. 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. Prefer non-static, non-inlined API entrypoint functions over internal static helper functions (which are inlined by the compiler and do not have distinct symbol addresses). 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. Also check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed for Kbuild to compile the code statically into vmlinux. 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 8946b90004708bfb398a9e7a7511aa50289fd0d2 Author: syz-cluster <triage@syzkaller.com> Date: Wed Aug 12 08:26:44 2026 +0000 syz-cluster: applied patch under review diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage index 7bfbb9cc2c113..bbdfae2c0caa6 100644 --- a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage +++ b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage @@ -10,9 +10,19 @@ Description: - hpage_pmd_size - khugepaged - shmem_enabled + - shrink_underused - use_zero_page - subdirectories of the form hugepages-<size>kB, where <size> is the page size of the hugepages supported by the kernel/CPU combination. See Documentation/admin-guide/mm/transhuge.rst for details. + +What: /sys/kernel/mm/transparent_hugepage/shrink_underused +Date: Sep 2024 +Contact: Linux memory management mailing list <linux-mm@kvack.org> +Description: Reading and writing this file controls whether khugepaged + splits underused transparent huge pages (THPs) under memory + pressure. A THP is considered underused when its number of + zero-filled pages is above max_ptes_none. Enabled by default; + writing 0 disables the splitting and 1 enables it. diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst index b187d618452f4..72e944f49da5b 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -389,14 +389,14 @@ is not defined within a valid ``thp_anon``, its policy will default to Similarly to ``transparent_hugepage``, you can control the hugepage allocation policy for the internal shmem mount by using the kernel parameter ``transparent_hugepage_shmem=<policy>``, where ``<policy>`` is one of the -seven valid policies for shmem (``always``, ``within_size``, ``advise``, +six valid policies for shmem (``always``, ``within_size``, ``advise``, ``never``, ``deny``, and ``force``). Similarly to ``transparent_hugepage_shmem``, you can control the default hugepage allocation policy for the tmpfs mount by using the kernel parameter ``transparent_hugepage_tmpfs=<policy>``, where ``<policy>`` is one of the -four valid policies for tmpfs (``always``, ``within_size``, ``advise``, -``never``). The tmpfs mount default policy is ``never``. +six valid policies for tmpfs (``always``, ``within_size``, ``advise``, +``never``, ``deny``, and ``force``). The tmpfs mount default policy is ``never``. Additionally, Kconfig options are available to set the default hugepage policies for shmem (``CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_*``) and tmpfs
3/2	2026/08/12 08:26	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 2600 output: 53 thoughts: 366 Thoughts: Analyzing the Patch for Fuzzing Eligibility Okay, so I've got this patch in front of me, and it seems to be solely focused on documentation updates. Specifically, I'm looking at changes to `Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage` and `Documentation/admin-guide/mm/transhuge.rst`. My first instinct is to double-check, of course, to ensure this is truly the entire scope of the changes. I need to be absolutely certain before making a determination. The commit message mentions something about "syz-cluster: applied patch under review", but that's a red herring at this point. I need to focus on the content of this patch. Let's see...I could use `git grep` or `git show` to verify, but wait, the prompt itself is saying that the diff provided is the complete diff. It states, "For your convenience, here is the diff of the changes". Alright, so the premise here is that the provided diff is the whole story. Let's verify that quickly, just to be sure. Yep, the diff only includes modifications to those two documentation files. I was tempted to look for related code such as 'shrink_underused', but I'm thinking the text implies that this is a self-contained documentation change. Therefore, given that the patch is solely modifying documentation files, and the prompt implies the diff is complete, I'm comfortable returning `WorthFuzzing=false`. It's a documentation-only change, and according to the instructions I was given, that means it's not relevant for fuzzing.
4/2	2026/08/12 08:26	tool	set-results	0m Args: { "EnableConfigs": [], "FocusSymbols": [], "Reasoning": "The patch only modifies Documentation files (ABI and admin-guide) and does not contain any functional code changes.", "WorthFuzzing": false } Results: { "EnableConfigs": null, "FocusSymbols": [], "Reasoning": "The patch only modifies Documentation files (ABI and admin-guide) and does not contain any functional code changes.", "WorthFuzzing": false }
5/1	2026/08/12 08:26	action	If	0m Args: { "WorthFuzzing": false } Results: null

Trajectory: (Expand/Collapse All)

Seq

Timestamp

Type

Name

Duration

0/0

2026/08/12 08:26

flow

patch-triage

Args:

null

Results:

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "KMSANReasoning": "",
  "NeedsKMSAN": false,
  "Reasoning": "The patch only modifies Documentation files (ABI and admin-guide) and does not contain any functional code changes.",
  "WorthFuzzing": false
}

1/1

2026/08/12 08:26

action

read-patch-diff

Args:

null

Results:

{
  "PatchDiff": "commit 8946b90004708bfb398a9e7a7511aa50289fd0d2\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Wed Aug 12 08:26:44 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage\nindex 7bfbb9cc2c113..bbdfae2c0caa6 100644\n--- a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage\n+++ b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage\n@@ -10,9 +10,19 @@ Description:\n \t\t\t- hpage_pmd_size\n \t\t\t- khugepaged\n \t\t\t- shmem_enabled\n+\t\t\t- shrink_underused\n \t\t\t- use_zero_page\n \t\t\t- subdirectories of the form hugepages-\u003csize\u003ekB, where \u003csize\u003e\n \t\t\t  is the page size of the hugepages supported by the kernel/CPU\n \t\t\t  combination.\n \n \t\tSee Documentation/admin-guide/mm/transhuge.rst for details.\n+\n+What:\t\t/sys/kernel/mm/transparent_hugepage/shrink_underused\n+Date:\t\tSep 2024\n+Contact:\tLinux memory management mailing list \u003clinux-mm@kvack.org\u003e\n+Description:\tReading and writing this file controls whether khugepaged\n+\t\tsplits underused transparent huge pages (THPs) under memory\n+\t\tpressure.  A THP is considered underused when its number of\n+\t\tzero-filled pages is above max_ptes_none.  Enabled by default;\n+\t\twriting 0 disables the splitting and 1 enables it.\ndiff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst\nindex b187d618452f4..72e944f49da5b 100644\n--- a/Documentation/admin-guide/mm/transhuge.rst\n+++ b/Documentation/admin-guide/mm/transhuge.rst\n@@ -389,14 +389,14 @@ is not defined within a valid ``thp_anon``, its policy will default to\n Similarly to ``transparent_hugepage``, you can control the hugepage\n allocation policy for the internal shmem mount by using the kernel parameter\n ``transparent_hugepage_shmem=\u003cpolicy\u003e``, where ``\u003cpolicy\u003e`` is one of the\n-seven valid policies for shmem (``always``, ``within_size``, ``advise``,\n+six valid policies for shmem (``always``, ``within_size``, ``advise``,\n ``never``, ``deny``, and ``force``).\n \n Similarly to ``transparent_hugepage_shmem``, you can control the default\n hugepage allocation policy for the tmpfs mount by using the kernel parameter\n ``transparent_hugepage_tmpfs=\u003cpolicy\u003e``, where ``\u003cpolicy\u003e`` is one of the\n-four valid policies for tmpfs (``always``, ``within_size``, ``advise``,\n-``never``). The tmpfs mount default policy is ``never``.\n+six valid policies for tmpfs (``always``, ``within_size``, ``advise``,\n+``never``, ``deny``, and ``force``). The tmpfs mount default policy is ``never``.\n \n Additionally, Kconfig options are available to set the default hugepage\n policies for shmem (``CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_*``) and tmpfs\n"
}

2/1

2026/08/12 08:26

agent

patch-evaluator

Model:

best-expensive

Args:

null

Results:

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies Documentation files (ABI and admin-guide) and does not contain any functional code changes.",
  "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).
- Code in vendor-specific PCIe switch, SmartNIC, or GPU drivers (e.g., mlxsw, pds_core, qed,
  ionic, amdgpu) that require physical PCIe hardware cards not emulated in standard QEMU.
- Driver .remove, .shutdown, or pci_unregister_driver teardown callbacks (e.g., igb_remove)
  that are executed only during PCI hot-unplug or sysfs driver unbind operations.

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.
   Prefer non-static, non-inlined API entrypoint functions over internal static helper functions
   (which are inlined by the compiler and do not have distinct symbol addresses).
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.
   Also check "depends on" lines in Kconfig to include any non-standard parent subsystem configs
   needed for Kbuild to compile the code statically into vmlinux. 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 8946b90004708bfb398a9e7a7511aa50289fd0d2
Author: syz-cluster <triage@syzkaller.com>
Date:   Wed Aug 12 08:26:44 2026 +0000

    syz-cluster: applied patch under review

diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage
index 7bfbb9cc2c113..bbdfae2c0caa6 100644
--- a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage
+++ b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage
@@ -10,9 +10,19 @@ Description:
 			- hpage_pmd_size
 			- khugepaged
 			- shmem_enabled
+			- shrink_underused
 			- use_zero_page
 			- subdirectories of the form hugepages-<size>kB, where <size>
 			  is the page size of the hugepages supported by the kernel/CPU
 			  combination.
 
 		See Documentation/admin-guide/mm/transhuge.rst for details.
+
+What:		/sys/kernel/mm/transparent_hugepage/shrink_underused
+Date:		Sep 2024
+Contact:	Linux memory management mailing list <linux-mm@kvack.org>
+Description:	Reading and writing this file controls whether khugepaged
+		splits underused transparent huge pages (THPs) under memory
+		pressure.  A THP is considered underused when its number of
+		zero-filled pages is above max_ptes_none.  Enabled by default;
+		writing 0 disables the splitting and 1 enables it.
diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst
index b187d618452f4..72e944f49da5b 100644
--- a/Documentation/admin-guide/mm/transhuge.rst
+++ b/Documentation/admin-guide/mm/transhuge.rst
@@ -389,14 +389,14 @@ is not defined within a valid ``thp_anon``, its policy will default to
 Similarly to ``transparent_hugepage``, you can control the hugepage
 allocation policy for the internal shmem mount by using the kernel parameter
 ``transparent_hugepage_shmem=<policy>``, where ``<policy>`` is one of the
-seven valid policies for shmem (``always``, ``within_size``, ``advise``,
+six valid policies for shmem (``always``, ``within_size``, ``advise``,
 ``never``, ``deny``, and ``force``).
 
 Similarly to ``transparent_hugepage_shmem``, you can control the default
 hugepage allocation policy for the tmpfs mount by using the kernel parameter
 ``transparent_hugepage_tmpfs=<policy>``, where ``<policy>`` is one of the
-four valid policies for tmpfs (``always``, ``within_size``, ``advise``,
-``never``). The tmpfs mount default policy is ``never``.
+six valid policies for tmpfs (``always``, ``within_size``, ``advise``,
+``never``, ``deny``, and ``force``). The tmpfs mount default policy is ``never``.
 
 Additionally, Kconfig options are available to set the default hugepage
 policies for shmem (``CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_*``) and tmpfs

3/2

2026/08/12 08:26

llm

patch-evaluator

Model:

gemini-3.1-pro-preview

Args:

null

Results:

null

Tokens:

							input: 2600
							output: 53
							thoughts: 366

Thoughts:

**Analyzing the Patch for Fuzzing Eligibility**

Okay, so I've got this patch in front of me, and it seems to be solely focused on documentation updates. Specifically, I'm looking at changes to `Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage` and `Documentation/admin-guide/mm/transhuge.rst`. My first instinct is to double-check, of course, to ensure this is truly the *entire* scope of the changes. I need to be absolutely certain before making a determination.

The commit message mentions something about "syz-cluster: applied patch under review", but that's a red herring at this point. I need to focus on the content of *this* patch. Let's see...I could use `git grep` or `git show` to verify, but wait, the prompt itself is saying that the diff provided *is* the complete diff. It states, "For your convenience, here is the diff of the changes". Alright, so the premise here is that the provided diff is the whole story.

Let's verify that quickly, just to be sure. Yep, the diff only includes modifications to those two documentation files. I was tempted to look for related code such as 'shrink_underused', but I'm thinking the text implies that this is a self-contained documentation change.

Therefore, given that the patch is *solely* modifying documentation files, and the prompt implies the diff is complete, I'm comfortable returning `WorthFuzzing=false`. It's a documentation-only change, and according to the instructions I was given, that means it's not relevant for fuzzing.

4/2

2026/08/12 08:26

tool

set-results

Args:

{
  "EnableConfigs": [],
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies Documentation files (ABI and admin-guide) and does not contain any functional code changes.",
  "WorthFuzzing": false
}

Results:

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies Documentation files (ABI and admin-guide) and does not contain any functional code changes.",
  "WorthFuzzing": false
}

5/1

2026/08/12 08:26

action

Args:

{
  "WorthFuzzing": false
}

Results:

null

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)