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)