Bug 2393157 (CVE-2025-38703) - CVE-2025-38703 kernel: drm/xe: Make dma-fences compliant with the safe access rules
Summary: CVE-2025-38703 kernel: drm/xe: Make dma-fences compliant with the safe access...
Keywords:
Status: NEW
Alias: CVE-2025-38703
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-09-04 16:01 UTC by OSIDB Bzimport
Modified: 2025-09-04 20:10 UTC (History)
0 users

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Description OSIDB Bzimport 2025-09-04 16:01:34 UTC
In the Linux kernel, the following vulnerability has been resolved:

drm/xe: Make dma-fences compliant with the safe access rules

Xe can free some of the data pointed to by the dma-fences it exports. Most
notably the timeline name can get freed if userspace closes the associated
submit queue. At the same time the fence could have been exported to a
third party (for example a sync_fence fd) which will then cause an use-
after-free on subsequent access.

To make this safe we need to make the driver compliant with the newly
documented dma-fence rules. Driver has to ensure a RCU grace period
between signalling a fence and freeing any data pointed to by said fence.

For the timeline name we simply make the queue be freed via kfree_rcu and
for the shared lock associated with multiple queues we add a RCU grace
period before freeing the per GT structure holding the lock.


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