From: Ming Lei <ming.lei@xxxxxxxxxx> commit b4459b11e84092658fa195a2587aff3b9637f0e7 upstream. DM uses blk-mq's quiesce/unquiesce to stop/start device mapper queue. But blk-mq's unquiesce may come from outside events, such as elevator switch, updating nr_requests or others, and request may come during suspend, so simply ask for blk-mq to requeue it. Fixes one kernel panic issue when running updating nr_requests and dm-mpath suspend/resume stress test. Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/dm-rq.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -490,6 +490,14 @@ static blk_status_t dm_mq_queue_rq(struc struct mapped_device *md = tio->md; struct dm_target *ti = md->immutable_target; + /* + * blk-mq's unquiesce may come from outside events, such as + * elevator switch, updating nr_requests or others, and request may + * come during suspend, so simply ask for blk-mq to requeue it. + */ + if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) + return BLK_STS_RESOURCE; + if (unlikely(!ti)) { int srcu_idx; struct dm_table *map = dm_get_live_table(md, &srcu_idx);