Bug 2513186 (CVE-2026-68233)

Summary: CVE-2026-68233 kernel: drm/vc4: Shut down BO cache timer before teardown
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the `drm/vc4` component of the Linux kernel. A logic error in the BO cache timer shutdown process allows the timer to be rearmed even after it has been destroyed. This can lead to work being queued again after teardown, potentially causing system instability or a denial of service (DoS) due to improper resource management.
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Description OSIDB Bzimport 2026-08-10 12:23:52 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/vc4: Shut down BO cache timer before teardown

The BO cache timer callback schedules time_work, and time_work can rearm
the timer through vc4_bo_cache_free_old().

vc4_bo_cache_destroy() deletes the timer and then cancels the work, which
does not break that cycle: the work being cancelled can rearm the timer,
and the timer then queues work again after teardown.

Use timer_shutdown_sync() instead, so the timer cannot be rearmed and the
cycle ends with cancel_work_sync().