Commit 4a60f360 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: don't dereference request after flush insertion 



We could have a race here, where the request gets freed before we call
into blk_mq_run_hw_queue(). If this happens, we cannot rely on the state
of the request.

Grab the hardware context before inserting the flush.

Fixes: 0f38d766 ("blk-mq: cleanup blk_mq_submit_bio")
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0f38d766

block/blk-mq.c

+2 −1
Original line number Diff line number Diff line
@@ -2284,9 +2284,10 @@ blk_qc_t blk_mq_submit_bio(struct bio *bio) 
	}



	if (unlikely(is_flush_fua)) {

		struct blk_mq_hw_ctx *hctx = rq->mq_hctx;

		/* Bypass scheduler for flush requests */

		blk_insert_flush(rq);

		blk_mq_run_hw_queue(rq->mq_hctx, true);

		blk_mq_run_hw_queue(hctx, true);

	} else if (plug && (q->nr_hw_queues == 1 ||

		   blk_mq_is_shared_tags(rq->mq_hctx->flags) ||

		   q->mq_ops->commit_rqs || !blk_queue_nonrot(q))) {