From e869b5462f83bcc771a3301fa7c8de47ed8c74f5 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Wed, 26 Apr 2017 13:47:52 -0700 Subject: [PATCH] blk-mq: Unregister debugfs attributes earlier 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 Reviewed-by: Hannes Reinecke Reviewed-by: Omar Sandoval Signed-off-by: Jens Axboe --- block/blk-core.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index a49b083..6bd4d17 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -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); -- 2.7.4