kevin/linux
1
Fork 0
Code

blk-ioc: fix recursive spin_lock/unlock_irq() in ioc_clear_queue()

Browse Source 
Recursive spin_lock/unlock_irq() is not safe, because spin_unlock_irq()
will enable irq unconditionally:

spin_lock_irq	queue_lock	-> disable irq
spin_lock_irq	ioc->lock
spin_unlock_irq ioc->lock	-> enable irq
/*
 * AA dead lock will be triggered if current context is preempted by irq,
 * and irq try to hold queue_lock again.
 */
spin_unlock_irq queue_lock

Fix this problem by using spin_lock/unlock() directly for 'ioc->lock'.

Fixes: 5a0ac57c48 ("blk-ioc: protect ioc_destroy_icq() by 'queue_lock'")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230606011438.3743440-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Yu Kuai 2023-06-06 09:14:38 +08:00 committed by Jens Axboe
parent f12bc113ce
commit a7cfa0af0c
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
block/blk-ioc.c
View File

@ -179,9 +179,9 @@ void ioc_clear_queue(struct request_queue *q)
* Other context won't hold ioc lock to wait for queue_lock, see
* details in ioc_release_fn().
*/
spin_lock_irq(&icq->ioc->lock);
spin_lock(&icq->ioc->lock);
ioc_destroy_icq(icq);
spin_unlock_irq(&icq->ioc->lock);
spin_unlock(&icq->ioc->lock);
}
spin_unlock_irq(&q->queue_lock);
}