Commit c25c0c90 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

blk-mq: setup queue ->tag_set before initializing hctx 



Commit 7b815817 ("blk-mq: add helper for checking if one CPU is mapped to specified hctx")
needs to check queue mapping via tag set in hctx's cpuhp handler.

However, q->tag_set may not be setup yet when the cpuhp handler is
enabled, then kernel oops is triggered.

Fix the issue by setup queue tag_set before initializing hctx.

Cc: stable@vger.kernel.org
Reported-and-tested-by: default avatarRick Koch <mr.rickkoch@gmail.com>
Closes: https://lore.kernel.org/linux-block/CANa58eeNDozLaBHKPLxSAhEy__FPfJT_F71W=sEQw49UCrC9PQ@mail.gmail.com


Fixes: 7b815817 ("blk-mq: add helper for checking if one CPU is mapped to specified hctx")
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJohn Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20241014005115.2699642-1-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ee7ff15b

block/blk-mq.c

+6 −2
Original line number Diff line number Diff line
@@ -4310,6 +4310,12 @@ int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, 
	/* mark the queue as mq asap */

	q->mq_ops = set->ops;



	/*

	 * ->tag_set has to be setup before initialize hctx, which cpuphp

	 * handler needs it for checking queue mapping

	 */

	q->tag_set = set;



	if (blk_mq_alloc_ctxs(q))

		goto err_exit;
@@ -4328,8 +4334,6 @@ int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, 
	INIT_WORK(&q->timeout_work, blk_mq_timeout_work);

	blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);



	q->tag_set = set;



	q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;



	INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);