]> git.karo-electronics.de Git - karo-tx-linux.git/commit
Avoid dereferencing a 'request_queue' after last close.
authorNeilBrown <neilb@suse.de>
Sat, 10 Sep 2011 07:20:21 +0000 (17:20 +1000)
committerNeilBrown <neilb@suse.de>
Sat, 10 Sep 2011 07:20:21 +0000 (17:20 +1000)
commit94007751bb02797ba87bac7aacee2731ac2039a3
treeac45ec9aef327e0a77f3ffd8c09eff9ef1609f95
parent43220aa0f22cd3ce5b30246d50ccd696d119edea
Avoid dereferencing a 'request_queue' after last close.

On the last close of an 'md' device which as been stopped, the device
is destroyed and in particular the request_queue is freed.  The free
is done in a separate thread so it might happen a short time later.

__blkdev_put calls bdev_inode_switch_bdi *after* ->release has been
called.

Since commit f758eeabeb96f878c860e8f110f94ec8820822a9
bdev_inode_switch_bdi will dereference the 'old' bdi, which lives
inside a request_queue, to get a spin lock.  This causes the last
close on an md device to sometime take a spin_lock which lives in
freed memory - which results in an oops.

So move the called to bdev_inode_switch_bdi before the call to
->release.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
fs/block_dev.c