CVE-2025-21911

/// Technical 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(res

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References