syzkaller is an automated fuzzer that generates kernel activity and uses code coverage to find bugs in operating-system kernels. It is used by kernel developers and security researchers to test Linux and other supported kernels for vulnerabilities and failures. The catalogue add-ons help coding agents operate or use syzkaller.
Borrowing it
Nothing to install: this file belongs to google/syzkaller. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/google/syzkaller/master/.agents/skills/linux-subsystems-update/SKILL.mdgit clone --depth 1 https://github.com/google/syzkallerWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/google/syzkaller/linux-subsystems-update)<a href="https://agentmods.dev/skills/google/syzkaller/linux-subsystems-update"><img src="https://agentmods.dev/badge/skills/google/syzkaller/linux-subsystems-update/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/google/syzkaller/linux-subsystems-update"><img src="https://agentmods.dev/badge/skills/google/syzkaller/linux-subsystems-update.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00093 | $0.01599 |
| Opus 5.5 | $0.00037 | $0.00640 |
| Sonnet 5.5 | $0.00019 | $0.00320 |
| Haiku 4.5 | $0.00009 | $0.00160 |
Grade A, and why
linux-subsystems-update scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Updating Linux Subsystems (pkg/subsystem/lists/linux.go)
Use this skill when updating or regenerating pkg/subsystem/lists/linux.go
or modifying the Linux subsystem extraction rules in pkg/subsystem/linux/.
Read the code in pkg/subsystem/linux/ (subsystems.go, rules.go, names.go, parents.go, maintainers.go)
as needed to understand how subsystems and hierarchies are inferred.
1. Obtaining a Linux Kernel Checkout (torvalds, NOT linux-next)
If the user has not provided a path to a Linux kernel checkout ($KERNEL_PATH), ask the user for one before running the generator.
[!IMPORTANT]
- Use upstream mainline (
torvalds/linux.git), NOTlinux-next. All subsystem list updates target mainline Linux, ideally checked out at the latest release or release candidate tag (e.g.,v6.19-rc6,v6.16-rc7) so the generated header comment and revision date reflect a mainline release tag.- Ensure the kernel working tree is clean. The generator walks source files in
$KERNEL_PATHto count files per subsystem and infer parent-child relationships. Untracked build artifacts or out-of-tree source files will skew file counts and parent inference.
2. Running syz-query-subsystems
Never hand-edit pkg/subsystem/lists/linux.go. Regenerate it via tools/syz-query-subsystems (run directly on the host so $KERNEL_PATH outside the repo is accessible):
go run ./tools/syz-query-subsystems \
-os linux \
-kernel "$KERNEL_PATH" \
-syzkaller . \
-name linux
- Pass
-debugto print the exact list of kernel source paths matched by each subsystem. - When investigating why a subsystem was dropped, merged, or assigned unexpected parents, it often helps to apply temporary debugging changes to
pkg/subsystem/linux/and re-runsyz-query-subsystemsto extract more information. Revert any temporary debugging code when done.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 3d ago First seen · 85 lines · 93 tokens per session scan A df0781b06e8c
linux-subsystems-update is a skill published in the GitHub repository google/syzkaller (6,383 stars, last pushed today), licensed Apache-2.0. It adds 93 tokens to every session and 1,599 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-26.
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