diff options
| author | Tejun Heo <tj@kernel.org> | 2011-06-01 08:27:41 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-06-23 15:05:32 -0700 |
| commit | b7f788ce3f4ad895fe29cb225765c54f59a64d4d (patch) | |
| tree | 06b8a704aa550d2ed88c5ed43e54da1589d2ab39 /fs | |
| parent | 344bfe4456acedc5087677dd84b5a1aaa3137f8b (diff) | |
block: blkdev_get() should access ->bd_disk only after success
commit 4c49ff3fe128ca68dabd07537415c419ad7f82f9 upstream.
d4dc210f69 (block: don't block events on excl write for non-optical
devices) added dereferencing of bdev->bd_disk to test
GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE; however, bdev->bd_disk can be
%NULL if open failed which can lead to an oops.
Test the flag after testing open was successful, not before.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: David Miller <davem@davemloft.net>
Tested-by: David Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/block_dev.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 1f2b19978333..1a2421f908f0 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1272,8 +1272,8 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) * individual writeable reference is too fragile given the * way @mode is used in blkdev_get/put(). */ - if ((disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE) && - !res && (mode & FMODE_WRITE) && !bdev->bd_write_holder) { + if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder && + (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { bdev->bd_write_holder = true; disk_block_events(disk); } |