CVE-2025-21911 drm/imagination: avoid deadlock on fence release
A deadlock in the Imagination DRM driver can cause a system hang, requiring a kernel patch to resolve.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-21911?
CVE-2025-21911 is a medium-severity vulnerability in Linux kernel, published on 1 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
drm/imagination: avoid deadlock on fence release
Do scheduler queue fence release processing on a workqueue, rather than in the release function itself.
Fixes deadlock issues such as the following:
[ 607.400437] ============================================ [ 607.405755] WARNING: possible recursive locking detected [ 607.415500] -------------------------------------------- [ 607.420817] weston:zfq0/24149 is trying to acquire lock: [ 607.426131] ffff000017d041a0 (reservation_ww_class_mutex){+.+.}-{3:3}, at: pvr_gem_object_vunmap+0x40/0xc0 [powervr] [ 607.436728] but task is already holding lock: [ 607.442554] ffff000017d105a0 (reservation_ww_class_mutex){+.+.}-{3:3}, at: dma_buf_ioctl+0x250/0x554 [ 607.451727] other info that might help us debug this: [ 607.458245] Possible unsafe locking scenario:
[ 607.464155] CPU0 [ 607.466601] ---- [ 607.469044] lock(reservation_ww_class_mutex); [ 607.473584] lock(reservation_ww_class_mutex); [ 607.478114] *** DEADLOCK ***
Weakness: CWE-667
Which versions are affected by CVE-2025-21911?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21911?
Apply the vendor's patch.
Is CVE-2025-21911 being exploited?
There is no known exploitation of CVE-2025-21911 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-21911, DEBIAN-CVE-2025-21911, GHSA-x9qw-9cw3-55vf, ROOT-OS-UBUNTU-2404-CVE-2025-21911, UBUNTU-CVE-2025-21911.