CVE-2024-43863

/// Technical description

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

drm/vmwgfx: Fix a deadlock in dma buf fence polling

Introduce a version of the fence ops that on release doesn't remove

the fence from the pending list, and thus doesn't require a lock to

fix poll->fence wait->fence unref deadlocks.

vmwgfx overwrites the wait callback to iterate over the list of all

fences and update their status, to do that it holds a lock to prevent

the list modifcations from other threads. The fence destroy callback

both deletes the fence and removes it from the list of pending

fences, for which it holds a lock.

dma buf polling cb unrefs a fence after it's been signaled: so the poll

calls the wait, which signals the fences, which are being destroyed.

The destruction tries to acquire the lock on the pending fences list

which it can never get because it's held by the wait from which it

was called.

Old bug, but not a lot of userspace apps were using dma-buf polling

interfaces. Fix those, in partic

/// 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