blk-ioc: fix recursive spin_lock/unlock_irq() in ioc_clear_queue()
authorYu Kuai <yukuai3@huawei.com>
Tue, 6 Jun 2023 01:14:38 +0000 (09:14 +0800)
committerJens Axboe <axboe@kernel.dk>
Wed, 7 Jun 2023 13:51:00 +0000 (07:51 -0600)
commita7cfa0af0c88353b4eb59db5a2a0fbe35329b3f9
tree9f9aa517dd1d92a702ecd776732fc5551ca6cbd4
parentf12bc113ce904777fd6ca003b473b427782b3dde
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>
block/blk-ioc.c