vulnerability
Debian: CVE-2024-41092: linux, linux-6.1 -- security update
Severity | CVSS | Published | Added | Modified |
---|---|---|---|---|
7 | (AV:L/AC:L/Au:S/C:C/I:C/A:C) | 07/29/2024 | 08/07/2024 | 01/30/2025 |
Description
In the Linux kernel, the following vulnerability has been resolved:
drm/i915/gt: Fix potential UAF by revoke of fence registers
CI has been sporadically reporting the following issue triggered by
igt@i915_selftest@live@hangcheck on ADL-P and similar machines:
...
active))
...
...
...
...
In the past, there were similar failures reported by CI from other IGT
tests, observed on other platforms.
Before commit 63baf4f3d587 ("drm/i915/gt: Only wait for GPU activity
before unbinding a GGTT fence"), i915_vma_revoke_fence() was waiting for
idleness of vma->active via fence_update(). That commit introduced
vma->fence->active in order for the fence_update() to be able to wait
selectively on that one instead of vma->active since only idleness of
fence registers was needed. But then, another commit 0d86ee35097a
("drm/i915/gt: Make fence revocation unequivocal") replaced the call to
fence_update() in i915_vma_revoke_fence() with only fence_write(), and
also added that GEM_BUG_ON(!i915_active_is_idle(&fence->active)) in front.
No justification was provided on why we might then expect idleness of
vma->fence->active without first waiting on it.
The issue can be potentially caused by a race among revocation of fence
registers on one side and sequential execution of signal callbacks invoked
on completion of a request that was using them on the other, still
processed in parallel to revocation of those fence registers. Fix it by
waiting for idleness of vma->fence->active in i915_vma_revoke_fence().
(cherry picked from commit 24bb052d3dd499c5956abad5f7d8e4fd07da7fb1)
Solution(s)

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