amdgpu_dma_buf_move_notify() touches the page tables without first
calling amdgpu_vm_ready(). When a process is SIGKILLed, its VM entities
are stopped. Teardown of an imported dma-buf then tries to clear PTEs by
submitting to one of those stopped entities. That eventually hangs the
task.
Commit aa5fc4362fac ("drm/amdgpu: fix task hang from failed job
submission during process kill") added the stopped entity check in
amdgpu_vm_ready() and used it in amdgpu_cs_vm_handling(). That did not
cover a call in amdgpu_dma_buf_move_notify(), what was already mentioned
in:
https://lists.freedesktop.org/archives/amd-gfx/2025-October/133076.html
Tested by SIGKILLing a GPU workload holding imported dma-bufs. Without
the patch "Trying to push to a killed entity" errors are logged, then a
task hangs. With the patch there are no hung tasks. This was tested on a
6.18 kernel.
Signed-off-by: Dariusz Marcinkiewicz <[email protected]>
Assisted-by: LLM
---
drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
index 9c80eef79e32..ee473a888331 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
@@ -481,6 +481,11 @@ amdgpu_dma_buf_move_notify(struct dma_buf_attachment
*attach)
continue;
}
+ if (!amdgpu_vm_ready(vm)) {
+ dma_resv_unlock(resv);
+ continue;
+ }
+
/* Reserve fences for two SDMA page table updates */
r = dma_resv_reserve_fences(resv, 2);
if (!r)
--
2.55.0.1082.g2b9226bbc0-goog
