Bug 2422749 (CVE-2025-68250) - CVE-2025-68250 kernel: hung_task: fix warnings caused by unaligned lock pointers
Summary: CVE-2025-68250 kernel: hung_task: fix warnings caused by unaligned lock pointers
Keywords:
Status: NEW
Alias: CVE-2025-68250
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-12-16 15:01 UTC by OSIDB Bzimport
Modified: 2025-12-16 23:03 UTC (History)
0 users

Fixed In Version:
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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!


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