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

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: 5a0ac57c48aa ("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>

diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index d5db92e..25dd4db 100644 (file)
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -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);
 }