From 294319fea7169f8a4abb48b1e9b3b98c7334e465 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Wed, 18 May 2011 16:20:10 +0200 Subject: [PATCH] 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 --- block/blk.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/blk.h b/block/blk.h index 1f798b5a6f19..1566e8d5d94e 100644 --- a/block/blk.h +++ b/block/blk.h @@ -81,7 +81,8 @@ static inline struct request *__elv_next_request(struct request_queue *q) q->flush_queue_delayed = 1; return NULL; } - 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; } } -- 2.39.5