Replace blk_mq_quiesce_queue_nowait() with blk_mq_quiesce_queue() in virtblk_freeze_priv(). Keep the existing freeze and unfreeze order. The synchronous call waits for dispatch code that was already running. The queue remains quiesced until virtblk_restore_priv() calls blk_mq_unquiesce_queue(). Fixes: 7678abee0867 ("virtio-blk: don't keep queue frozen during system suspend") Signed-off-by: Cong Zhang --- blk_mq_run_work_fn() can call blk_mq_sched_dispatch_requests() through blk_mq_run_dispatch_ops(). The dispatcher checks QUEUE_FLAG_QUIESCED while the flag is clear. It can then be preempted before it gets a request. At that time, it has no queue usage reference, so blk_mq_freeze_queue() does not wait for it. virtblk_freeze_priv() then calls blk_mq_quiesce_queue_nowait() and blk_mq_unfreeze_queue(). A new request can enter the queue. The old dispatcher can run again, use its old flag check, get the new request, and call virtio_queue_rq(). At the same time, virtblk_freeze_priv() can reset the device, delete the virtqueues, and free vblk->vqs. The old dispatcher can then use a deleted virtqueue or a NULL vblk->vqs, and the kernel can crash. --- drivers/block/virtio_blk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 32bf3ba07a9d..7a570591e040 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -1595,7 +1595,7 @@ static int virtblk_freeze_priv(struct virtio_device *vdev) /* Ensure no requests in virtqueues before deleting vqs. */ memflags = blk_mq_freeze_queue(q); - blk_mq_quiesce_queue_nowait(q); + blk_mq_quiesce_queue(q); blk_mq_unfreeze_queue(q, memflags); /* Ensure we don't receive any more interrupts */ --- base-commit: 50d05c7c76c96b90462f24debacca971d2e86713 change-id: 20260910-virtblk_sync_quiesce-9b2c88d45416 Best regards, -- Cong Zhang