From: James Bottomley Date: Wed, 18 May 2011 14:20:10 +0000 (+0200) Subject: block: add proper state guards to __elv_next_request X-Git-Tag: v2.6.35.14~156 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0871ccb857a76c76be1e4c8b3d1dfdd7f3e91fe7;p=karo-tx-linux.git block: add proper state guards to __elv_next_request commit 0a58e077eb600d1efd7e54ad9926a75a39d7f8ae upstream. blk_cleanup_queue() calls elevator_exit() and after this, we can't touch the elevator without oopsing. __elv_next_request() must check for this state because in the refcounted queue model, we can still call it after blk_cleanup_queue() has been called. This was reported as causing an oops attributable to scsi. Signed-off-by: James Bottomley Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen --- diff --git a/block/blk.h b/block/blk.h index 5ee3d7e72feb..141483695145 100644 --- a/block/blk.h +++ b/block/blk.h @@ -62,7 +62,8 @@ static inline struct request *__elv_next_request(struct request_queue *q) return rq; } - if (!q->elevator->ops->elevator_dispatch_fn(q, 0)) + if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) || + !q->elevator->ops->elevator_dispatch_fn(q, 0)) return NULL; } }