Bug 2422707 (CVE-2025-68223)

Summary: CVE-2025-68223 kernel: drm/radeon: delete radeon_fence_process in is_signaled, no deadlock
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was identified in the Linux kernel’s Radeon DRM driver involving self-deadlock risk when checking whether a dma_fence_ops::signaled fence has been signaled. In certain execution paths, the fence lock is also the wait queue lock for Radeon, and attempting to make forward progress on the wait queue while holding an unknown-state fence lock could result in a self-deadlock. Upstream patches remove the unnecessary queue progress attempt during the is_signaled check, eliminating the deadlock scenario while still correctly handling false signal results
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Description OSIDB Bzimport 2025-12-16 14:05:25 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/radeon: delete radeon_fence_process in is_signaled, no deadlock

Delete the attempt to progress the queue when checking if fence is
signaled. This avoids deadlock.

dma-fence_ops::signaled can be called with the fence lock in unknown
state. For radeon, the fence lock is also the wait queue lock. This can
cause a self deadlock when signaled() tries to make forward progress on
the wait queue. But advancing the queue is unneeded because incorrectly
returning false from signaled() is perfectly acceptable.

(cherry picked from commit 527ba26e50ec2ca2be9c7c82f3ad42998a75d0db)
Comment 1 Alexander B 2025-12-17 01:36:49 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025121634-CVE-2025-68223-4e44@gregkh/T