Bug 2461451 (CVE-2026-31566)

Summary: CVE-2026-31566 kernel: drm/amdgpu: Fix fence put before wait in amdgpu_amdkfd_submit_ib
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's AMD GPU (amdgpu) driver. An issue in the `amdgpu_amdkfd_submit_ib` function allows a local user to trigger a use-after-free vulnerability. This occurs because a fence reference is incorrectly released before waiting for job completion, potentially freeing the memory prematurely. This could lead to system instability or denial of service.
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Description OSIDB Bzimport 2026-04-24 15:02:13 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: Fix fence put before wait in amdgpu_amdkfd_submit_ib

amdgpu_amdkfd_submit_ib() submits a GPU job and gets a fence
from amdgpu_ib_schedule(). This fence is used to wait for job
completion.

Currently, the code drops the fence reference using dma_fence_put()
before calling dma_fence_wait().

If dma_fence_put() releases the last reference, the fence may be
freed before dma_fence_wait() is called. This can lead to a
use-after-free.

Fix this by waiting on the fence first and releasing the reference
only after dma_fence_wait() completes.

Fixes the below:
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c:697 amdgpu_amdkfd_submit_ib() warn: passing freed memory 'f' (line 696)

(cherry picked from commit 8b9e5259adc385b61a6590a13b82ae0ac2bd3482)
Comment 1 Keith Grant 2026-04-24 17:50:49 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042400-CVE-2026-31566-2d8b@gregkh/T