Re: [bug report] kmemleak observed from blktests on latest linux-block/for-next

[Ming Lei <ming.lei@redhat.com>]

On Mon, Jun 13, 2022 at 09:08:11PM +0800, Yi Zhang wrote:
> Hi Ming
> 
> The kmemleak also can be reproduced on 5.19.0-rc2, pls try to enable
> nvme_core multipath and retest.
> 
> # cat /sys/module/nvme_core/parameters/multipath
> Y
>

OK, I can understand the reason now since rqos is only removed for blk-mq queue,
then rqos allocated for bio queue is leaked, see disk_release_mq().

The following patch should fix it:

diff --git a/block/genhd.c b/block/genhd.c
index 556d6e4b38d9..6e7ca8c302aa 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1120,9 +1120,10 @@ static const struct attribute_group *disk_attr_groups[] = {
 	NULL
 };
 
-static void disk_release_mq(struct request_queue *q)
+static void disk_release_queue(struct request_queue *q)
 {
-	blk_mq_cancel_work_sync(q);
+	if (queue_is_mq(q))
+		blk_mq_cancel_work_sync(q);
 
 	/*
 	 * There can't be any non non-passthrough bios in flight here, but
@@ -1166,8 +1167,7 @@ static void disk_release(struct device *dev)
 	might_sleep();
 	WARN_ON_ONCE(disk_live(disk));
 
-	if (queue_is_mq(disk->queue))
-		disk_release_mq(disk->queue);
+	disk_release_queue(disk->queue);
 
 	blkcg_exit_queue(disk->queue);
 

Thanks,
Ming