From: Yu Kuai <yukuai3@xxxxxxxxxx>
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@xxxxxxxxxx>
---
block/blk-ioc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index d5db92e62c43..25dd4db11121 100644
--- 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);
}
--
2.39.2
