CVE-2025-21694

Summary

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.

Impact & exploitability

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products we track (1)

Recommendation

Apply the vendor fix in your normal patch cycle. Open any affected product above for its exact safe version.

Official patch: https://git.kernel.org/stable/c/649b266606bc413407ce315f710c8ce8a88ee30a ↗

Additional information

• NVD record
• https://git.kernel.org/stable/c/649b266606bc413407ce315f710c8ce8a88ee30aPatch
• https://git.kernel.org/stable/c/65c367bd9d4f43513c7f837df5753bea9561b836Patch
• https://git.kernel.org/stable/c/80828540dad0757b6337c6561d49c81038f38d87Patch
• https://git.kernel.org/stable/c/80da29deb88a3a907441fc35bb7bac309f31e713Patch
• https://git.kernel.org/stable/c/84c4ed15626574c9ac6c1039ba9c137a77bcc7f2Patch
• https://git.kernel.org/stable/c/a5a2ee8144c3897d37403a69118c3e3dc5713958Patch
• https://git.kernel.org/stable/c/cbc5dde0a461240046e8a41c43d7c3b76d5db952Patch
• https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html