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CVE-2024-43863

UNKNOWN
Published 2024-08-20T23:45:27.756Z
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No CVSS data available

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 particular this fixes KDE stalls/deadlock.

Available Exploits

No exploits available for this CVE.

Related News

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Affected Products

GitHub Security Advisories

Community-driven vulnerability intelligence from GitHub

⚠ Unreviewed MODERATE

GHSA-f95q-fwq6-mx8w

Advisory Details

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 particular this fixes KDE stalls/deadlock.

CVSS Scoring

CVSS Score

5.0

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Advisory provided by GitHub Security Advisory Database. Published: August 21, 2024, Modified: June 4, 2025

References

Published: 2024-08-20T23:45:27.756Z
Last Modified: 2025-06-04T12:57:17.071Z
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