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Message-Id: <20110928220151.100485943@clark.kroah.org>
Date: Wed, 28 Sep 2011 15:03:28 -0700
From: Greg KH <gregkh@...e.de>
To: linux-kernel@...r.kernel.org, stable@...nel.org
Cc: stable-review@...nel.org, torvalds@...ux-foundation.org,
akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
Hannes Reinecke <hare@...e.de>, Jens Axboe <axboe@...nel.dk>
Subject: [244/244] block: Free queue resources at blk_release_queue()
3.0-stable review patch. If anyone has any objections, please let us know.
------------------
From: Hannes Reinecke <hare@...e.de>
commit 777eb1bf15b8532c396821774bf6451e563438f5 upstream.
A kernel crash is observed when a mounted ext3/ext4 filesystem is
physically removed. The problem is that blk_cleanup_queue() frees up
some resources eg by calling elevator_exit(), which are not checked for
in normal operation. So we should rather move these calls to the
destructor function blk_release_queue() as at that point all remaining
references are gone. However, in doing so we have to ensure that any
externally supplied queue_lock is disconnected as the driver might free
up the lock after the call of blk_cleanup_queue(),
Signed-off-by: Hannes Reinecke <hare@...e.de>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>
---
block/blk-core.c | 13 ++++++-------
block/blk-sysfs.c | 5 +++++
2 files changed, 11 insertions(+), 7 deletions(-)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -348,9 +348,10 @@ void blk_put_queue(struct request_queue
EXPORT_SYMBOL(blk_put_queue);
/*
- * Note: If a driver supplied the queue lock, it should not zap that lock
- * unexpectedly as some queue cleanup components like elevator_exit() and
- * blk_throtl_exit() need queue lock.
+ * Note: If a driver supplied the queue lock, it is disconnected
+ * by this function. The actual state of the lock doesn't matter
+ * here as the request_queue isn't accessible after this point
+ * (QUEUE_FLAG_DEAD is set) and no other requests will be queued.
*/
void blk_cleanup_queue(struct request_queue *q)
{
@@ -367,10 +368,8 @@ void blk_cleanup_queue(struct request_qu
queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
mutex_unlock(&q->sysfs_lock);
- if (q->elevator)
- elevator_exit(q->elevator);
-
- blk_throtl_exit(q);
+ if (q->queue_lock != &q->__queue_lock)
+ q->queue_lock = &q->__queue_lock;
blk_put_queue(q);
}
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -472,6 +472,11 @@ static void blk_release_queue(struct kob
blk_sync_queue(q);
+ if (q->elevator)
+ elevator_exit(q->elevator);
+
+ blk_throtl_exit(q);
+
if (rl->rq_pool)
mempool_destroy(rl->rq_pool);
--
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