From 7150850146ebfa4ca998f653f264b8df6f7f85be Mon Sep 17 00:00:00 2001 From: Srinivasan Shanmugam Date: Mon, 23 Mar 2026 13:41:18 +0530 Subject: drm/amdgpu: Fix fence put before wait in amdgpu_amdkfd_submit_ib MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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) Fixes: 9ae55f030dc5 ("drm/amdgpu: Follow up change to previous drm scheduler change.") Cc: Felix Kuehling Cc: Dan Carpenter Cc: Christian König Cc: Alex Deucher Signed-off-by: Srinivasan Shanmugam Reviewed-by: Christian König Signed-off-by: Alex Deucher (cherry picked from commit 8b9e5259adc385b61a6590a13b82ae0ac2bd3482) --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c index 40c22438b1d2..4f27c75abedb 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c @@ -692,9 +692,9 @@ int amdgpu_amdkfd_submit_ib(struct amdgpu_device *adev, goto err_ib_sched; } - /* Drop the initial kref_init count (see drm_sched_main as example) */ - dma_fence_put(f); ret = dma_fence_wait(f, false); + /* Drop the returned fence reference after the wait completes */ + dma_fence_put(f); err_ib_sched: amdgpu_job_free(job); -- cgit v1.3