Bug 2422749 (CVE-2025-68250)

Summary: CVE-2025-68250 kernel: hung_task: fix warnings caused by unaligned lock pointers
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-12-16 15:01:51 UTC 
In the Linux kernel, the following vulnerability has been resolved:

hung_task: fix warnings caused by unaligned lock pointers

The blocker tracking mechanism assumes that lock pointers are at least
4-byte aligned to use their lower bits for type encoding.

However, as reported by Eero Tamminen, some architectures like m68k
only guarantee 2-byte alignment of 32-bit values. This breaks the
assumption and causes two related WARN_ON_ONCE checks to trigger.

To fix this, the runtime checks are adjusted to silently ignore any lock
that is not 4-byte aligned, effectively disabling the feature in such
cases and avoiding the related warnings.

Thanks to Geert Uytterhoeven for bisecting!
Comment 1 Alexander B 2025-12-16 22:58:38 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025121623-CVE-2025-68250-9b9c@gregkh/T