Patch "drm/amdkfd: Walk through list with dqm lock hold" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/amdkfd: Walk through list with dqm lock hold

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amdkfd-walk-through-list-with-dqm-lock-hold.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 691c33ad57561937991113c95f1ac830073e1e92
Author: xinhui pan <xinhui.pan@xxxxxxx>
Date:   Tue Jun 15 15:11:07 2021 +0800

    drm/amdkfd: Walk through list with dqm lock hold
    
    [ Upstream commit 56f221b6389e7ab99c30bbf01c71998ae92fc584 ]
    
    To avoid any list corruption.
    
    Signed-off-by: xinhui pan <xinhui.pan@xxxxxxx>
    Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
    Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
index ab69898c9cb7..723ec6c2830d 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -1584,7 +1584,7 @@ static int process_termination_cpsch(struct device_queue_manager *dqm,
 		struct qcm_process_device *qpd)
 {
 	int retval;
-	struct queue *q, *next;
+	struct queue *q;
 	struct kernel_queue *kq, *kq_next;
 	struct mqd_manager *mqd_mgr;
 	struct device_process_node *cur, *next_dpn;
@@ -1639,24 +1639,26 @@ static int process_termination_cpsch(struct device_queue_manager *dqm,
 		qpd->reset_wavefronts = false;
 	}
 
-	dqm_unlock(dqm);
-
-	/* Outside the DQM lock because under the DQM lock we can't do
-	 * reclaim or take other locks that others hold while reclaiming.
-	 */
-	if (found)
-		kfd_dec_compute_active(dqm->dev);
-
 	/* Lastly, free mqd resources.
 	 * Do free_mqd() after dqm_unlock to avoid circular locking.
 	 */
-	list_for_each_entry_safe(q, next, &qpd->queues_list, list) {
+	while (!list_empty(&qpd->queues_list)) {
+		q = list_first_entry(&qpd->queues_list, struct queue, list);
 		mqd_mgr = dqm->mqd_mgrs[get_mqd_type_from_queue_type(
 				q->properties.type)];
 		list_del(&q->list);
 		qpd->queue_count--;
+		dqm_unlock(dqm);
 		mqd_mgr->free_mqd(mqd_mgr, q->mqd, q->mqd_mem_obj);
+		dqm_lock(dqm);
 	}
+	dqm_unlock(dqm);
+
+	/* Outside the DQM lock because under the DQM lock we can't do
+	 * reclaim or take other locks that others hold while reclaiming.
+	 */
+	if (found)
+		kfd_dec_compute_active(dqm->dev);
 
 	return retval;
 }