FAILED: patch "[PATCH] drm/amdgpu/userq: wait for GPU reset before mapping or unmapping queues" failed to apply to 6.6-stable tree

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 623507b8f4fe24851b2f1cb2c177f8ae3c8584b8
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '[email protected]' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 623507b8f4fe24851b2f1cb2c177f8ae3c8584b8 Mon Sep 17 00:00:00 2001
From: Prike Liang <[email protected]>
Date: Fri, 16 Oct 2026 09:34:32 +0800
Subject: [PATCH] drm/amdgpu/userq: wait for GPU reset before mapping or
unmapping queues

The user queue map and unmap helpers talk to the MES, but only the create path holds reset_domain->sem around them. The eviction, restore, destroy and suspend paths can submit to the MES while a GPU reset is in progress:

  WARNING: amdgpu_device.c:928 at amdgpu_device_skip_hw_access+0x73/0x90 [amdgpu]
  Workqueue: events amdgpu_eviction_fence_suspend_worker [amdgpu]
  Call Trace:
   amdgpu_mm_wdoorbell64+0x20/0x70 [amdgpu]
   mes_v11_0_ring_set_wptr+0x71/0x80 [amdgpu]
   amdgpu_ring_commit+0x5b/0xa0 [amdgpu]
   mes_v11_0_submit_pkt_and_poll_completion.constprop.0+0x207/0x520 [amdgpu]
   mes_v11_0_remove_hw_queue+0xd9/0x100 [amdgpu]
   mes_userq_unmap+0xc3/0x140 [amdgpu]
   amdgpu_userq_unmap_helper+0x67/0x280 [amdgpu]
   amdgpu_userq_evict+0x52/0xf0 [amdgpu]
   amdgpu_eviction_fence_suspend_worker+0x55/0xe0 [amdgpu]

Take the semaphore for read in the helpers instead, around both the MES call and the queue state check and update. The reset changes the queue state from amdgpu_userq_pre_reset()/post_reset(), so every caller now waits for a running reset and acts on the state it left behind.

---
 drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

index 4dca1ab48410a..958a3c9f4c617 100644
@@ -362,6 +362,8 @@ static int amdgpu_userq_unmap_helper(struct amdgpu_usermode_queue *queue)
 		adev->userq_funcs[queue->queue_type];
 	int r;
 
+	/* The reset changes the queue state and the MES is unusable meanwhile */
+	guard(rwsem_read)(&adev->reset_domain->sem);
 	if ((queue->state == AMDGPU_USERQ_STATE_MAPPED) ||
 	    (queue->state == AMDGPU_USERQ_STATE_PREEMPTED)) {
 		trace_amdgpu_userq_state_start(queue);

@@ -388,6 +390,8 @@ static int amdgpu_userq_map_helper(struct amdgpu_usermode_queue *queue)
 		adev->userq_funcs[queue->queue_type];
 	int r;
 
+	/* The reset changes the queue state and the MES is unusable meanwhile */
+	guard(rwsem_read)(&adev->reset_domain->sem);
 	if (queue->state == AMDGPU_USERQ_STATE_UNMAPPED) {
 		trace_amdgpu_userq_state_start(queue);
 

@@ -769,12 +773,7 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args)
 	if (!adev->userq_halt_for_enforce_isolation ||
 	    ((queue->queue_type != AMDGPU_HW_IP_GFX) &&
 	     (queue->queue_type != AMDGPU_HW_IP_COMPUTE))) {
-		/* Serialize the map against an in-progress GPU reset (MES is
-		 * unresponsive during recovery), matching amdgpu_userq_detach_doorbell().
-		 */
-		down_read(&adev->reset_domain->sem);
 		r = amdgpu_userq_map_helper(queue);
-		up_read(&adev->reset_domain->sem);
 		if (r) {
 			drm_file_err(uq_mgr->file, "Failed to map Queue\n");
 			trace_amdgpu_userq_create_end(queue, r);

2.53.0