CVE-2025-40329
Linux Kernel DRM Fence Lock Deadlock
Description
In the Linux kernel, the following vulnerability has been resolved: drm/sched: Fix deadlock in drm_sched_entity_kill_jobs_cb The Mesa issue referenced below pointed out a possible deadlock: [ 1231.611031] Possible interrupt unsafe locking scenario: [ 1231.611033] CPU0 CPU1 [ 1231.611034] ---- ---- [ 1231.611035] lock(&xa->xa_lock#17); [ 1231.611038] local_irq_disable(); [ 1231.611039] lock(&fence->lock); [ 1231.611041] lock(&xa->xa_lock#17); [ 1231.611044] <Interrupt> [ 1231.611045] lock(&fence->lock); [ 1231.611047] *** DEADLOCK *** In this example, CPU0 would be any function accessing job->dependencies through the xa_* functions that don't disable interrupts (eg: drm_sched_job_add_dependency(), drm_sched_entity_kill_jobs_cb()). CPU1 is executing drm_sched_entity_kill_jobs_cb() as a fence signalling callback so in an interrupt context. It will deadlock when trying to grab the xa_lock which is already held by CPU0. Replacing all xa_* usage by their xa_*_irq counterparts would fix this issue, but Christian pointed out another issue: dma_fence_signal takes fence.lock and so does dma_fence_add_callback. dma_fence_signal() // locks f1.lock -> drm_sched_entity_kill_jobs_cb() -> foreach dependencies -> dma_fence_add_callback() // locks f2.lock This will deadlock if f1 and f2 share the same spinlock. To fix both issues, the code iterating on dependencies and re-arming them is moved out to drm_sched_entity_kill_jobs_work(). [phasta: commit message nits]
INFO
Published Date :
Dec. 9, 2025, 6:28 a.m.
Last Modified :
Dec. 9, 2025, 6:28 a.m.
Remotely Exploit :
No
Source :
None
Solution
- Apply the Linux kernel patch.
- Update the DRM scheduler component.
- Review related locking mechanisms.
- Test the system for deadlocks.
References to Advisories, Solutions, and Tools
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CVE-2025-40329.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-40329 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-40329
weaknesses.
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