drm/amdgpu/userq: fix indefinite fence wait during GPU reset

pre_reset only force-completes fences of MAPPED queues. A queue in any
other state (e.g. mid-eviction) keeps its last_fence pending; after a
GPU reset that fence never signals, so the eviction/suspend worker and
process teardown (amdgpu_evf_mgr_flush_suspend) wait on it forever and
wedge the machine:

  INFO: task kworker/6:28 blocked for more than 120 seconds.
  Workqueue: events amdgpu_eviction_fence_suspend_worker [amdgpu]
  Call Trace:
   dma_fence_wait_timeout+0x7e/0x130
   amdgpu_userq_evict+0x67/0x140 [amdgpu]
   amdgpu_eviction_fence_suspend_worker+0xd8/0x160 [amdgpu]
   process_scheduled_works+0xa6/0x420

Force-complete every queue's fence regardless of state. The unmap and
mark-hung step stays gated on MAPPED, since unmapping a queue that is
not mapped is invalid.

Fixes: 290f46cf5726 ("drm/amdgpu: Implement user queue reset functionality")
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 9102b39fa924dcc3dc75a3137bfa9633c40b88c0)
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
index d854343b3734d57393f6a6dd3b102d9af1b4f156..572f2949cb64eaad1d4cde711327dd112c36a951 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
@@ -1376,16 +1376,19 @@ void amdgpu_userq_pre_reset(struct amdgpu_device *adev)
 
        /* TODO: We probably need a new lock for the queue state */
        xa_for_each(&adev->userq_doorbell_xa, queue_id, queue) {
-               if (queue->state != AMDGPU_USERQ_STATE_MAPPED)
-                       continue;
-
-               userq_funcs = adev->userq_funcs[queue->queue_type];
-               userq_funcs->unmap(queue);
-               /* just mark all queues as hung at this point.
-                * if unmap succeeds, we could map again
-                * in amdgpu_userq_post_reset() if vram is not lost
+               if (queue->state == AMDGPU_USERQ_STATE_MAPPED) {
+                       userq_funcs = adev->userq_funcs[queue->queue_type];
+                       userq_funcs->unmap(queue);
+                       /* just mark all queues as hung at this point.
+                        * if unmap succeeds, we could map again
+                        * in amdgpu_userq_post_reset() if vram is not lost
+                        */
+                       queue->state = AMDGPU_USERQ_STATE_HUNG;
+               }
+               /* Force-complete any pending fence regardless of queue state so
+                * that eviction/suspend and queue teardown waiters don't block
+                * forever on a fence that will never signal after the reset.
                 */
-               queue->state = AMDGPU_USERQ_STATE_HUNG;
                amdgpu_userq_fence_driver_force_completion(queue);
        }
 }