CVE-2025-21849

In the Linux kernel, the following vulnerability has been resolved:

drm/i915/gt: Use spin_lock_irqsave() in interruptible context

spin_lock/unlock() functions used in interrupt contexts could result in a deadlock, as seen in GitLab issue #13399, which occurs when interrupt comes in while holding a lock.

Try to remedy the problem by saving irq state before spin lock acquisition.

v2: add irqs state save/restore calls to all locks/unlocks in signal_irq_work() execution (Maciej)

v3: use with spin_lock_irqsave() in guc_lrc_desc_unpin() instead of other lock/unlock calls and add Fixes and Cc tags (Tvrtko); change title and commit message

(cherry picked from commit c088387ddd6482b40f21ccf23db1125e8fa4af7e)

Weakness

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Software

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/25.html
• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/27.html

References

• https://git.kernel.org/stable/c/2bf1f4c129db7a10920655b000f0292f1ee509c2
• https://git.kernel.org/stable/c/47ae46ac5407646420e06b78e0dad331e56a4bb4
• https://git.kernel.org/stable/c/e49477f7f78598295551d486ecc7f020d796432e