Commit 7ad58c02 authored Oct 23, 2010 by Jens Axboe

block: fix use-after-free bug in blk throttle code



blk_throtl_exit() frees the throttle data hanging off the queue
in blk_cleanup_queue(), but blk_put_queue() will indirectly
dereference this data when calling blk_sync_queue() which in
turns calls throtl_shutdown_timer_wq().

Fix this by moving the freeing of the throttle data to when
the queue is truly being released, and post the call to
blk_sync_queue().

Reported-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

parent 7f388396

block/blk-core.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -462,8 +462,6 @@ void blk_cleanup_queue(struct request_queue *q)
		if (q->elevator)
		elevator_exit(q->elevator);

		blk_throtl_exit(q);

		blk_put_queue(q);
		}
		EXPORT_SYMBOL(blk_cleanup_queue);

block/blk-sysfs.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -471,6 +471,8 @@ static void blk_release_queue(struct kobject *kobj)

		blk_sync_queue(q);

		blk_throtl_exit(q);

		if (rl->rq_pool)
		mempool_destroy(rl->rq_pool);

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