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blk-mq: Unregister debugfs attributes earlier

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We currently call blk_mq_free_queue() from blk_cleanup_queue()
before we unregister the debugfs attributes for that queue in
blk_release_queue(). This leaves a window open during which
accessing most of the mq debugfs attributes would cause a
use-after-free. Additionally, the "state" attribute allows
running the queue, which we should not do after the queue has
entered the "dead" state. Fix both cases by unregistering the
debugfs attributes before freeing queue resources starts.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Bart Van Assche 2017-04-26 13:47:52 -07:00 committed by Jens Axboe
parent f05d1ba787
commit e869b5462f
1 changed files with 6 additions and 2 deletions
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8
block/blk-core.c
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@ -563,9 +563,13 @@ void blk_cleanup_queue(struct request_queue *q)
* prevent that q->request_fn() gets invoked after draining finished.
*/
blk_freeze_queue(q);
spin_lock_irq(lock);
if (!q->mq_ops)
if (!q->mq_ops) {
spin_lock_irq(lock);
__blk_drain_queue(q, true);
} else {
blk_mq_debugfs_unregister_mq(q);
spin_lock_irq(lock);
}
queue_flag_set(QUEUE_FLAG_DEAD, q);
spin_unlock_irq(lock);