Bug 2324569 (CVE-2024-50187)

Summary: CVE-2024-50187 kernel: drm/vc4: Stop the active perfmon before being destroyed
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Bug Depends On: 2324694    
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Description OSIDB Bzimport 2024-11-08 13:45:57 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/vc4: Stop the active perfmon before being destroyed

Upon closing the file descriptor, the active performance monitor is not
stopped. Although all perfmons are destroyed in `vc4_perfmon_close_file()`,
the active performance monitor's pointer (`vc4->active_perfmon`) is still
retained.

If we open a new file descriptor and submit a few jobs with performance
monitors, the driver will attempt to stop the active performance monitor
using the stale pointer in `vc4->active_perfmon`. However, this pointer
is no longer valid because the previous process has already terminated,
and all performance monitors associated with it have been destroyed and
freed.

To fix this, when the active performance monitor belongs to a given
process, explicitly stop it before destroying and freeing it.
Comment 1 Robb Gatica 2024-11-08 15:36:09 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024110835-CVE-2024-50187-f2b0@gregkh/T