CVE-2025-21694

NameCVE-2025-21694
DescriptionIn 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bullseye5.10.223-1vulnerable
bullseye (security)5.10.226-1vulnerable
bookworm6.1.123-1vulnerable
bookworm (security)6.1.128-1fixed
trixie6.12.12-1fixed
sid6.12.15-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebookworm6.1.128-1
linuxsource(unstable)6.12.11-1

Notes

https://git.kernel.org/linus/cbc5dde0a461240046e8a41c43d7c3b76d5db952 (6.13)

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