Affected: Linux

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)