diff options
| author | Jan Kara <jack@suse.cz> | 2010-09-16 20:36:36 +0200 |
|---|---|---|
| committer | Andi Kleen <ak@linux.intel.com> | 2010-12-14 23:40:00 +0100 |
| commit | 381709fcb98acf7803be64ceab5e49e2fc0dbbdb (patch) | |
| tree | 0cbb5565c3b3b034dff5a92026c2ff3b0756ae59 /block | |
| parent | 97d388bb0a4d7e5acc7274645382adac50260096 (diff) | |
block: Fix race during disk initialization
commit 01ea50638bc04ca5259f5711fcdedefcdde1cf43 upstream.
When a new disk is being discovered, add_disk() first ties the bdev to gendisk
(via register_disk()->blkdev_get()) and only after that calls
bdi_register_bdev(). Because register_disk() also creates disk's kobject, it
can happen that userspace manages to open and modify the device's data (or
inode) before its BDI is properly initialized leading to a warning in
__mark_inode_dirty().
Fix the problem by registering BDI early enough.
This patch addresses https://bugzilla.kernel.org/show_bug.cgi?id=16312
Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/genhd.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/block/genhd.c b/block/genhd.c index 59a2db6fecef..315afd2f2088 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -541,13 +541,15 @@ void add_disk(struct gendisk *disk) disk->major = MAJOR(devt); disk->first_minor = MINOR(devt); + /* Register BDI before referencing it from bdev */ + bdi = &disk->queue->backing_dev_info; + bdi_register_dev(bdi, disk_devt(disk)); + blk_register_region(disk_devt(disk), disk->minors, NULL, exact_match, exact_lock, disk); register_disk(disk); blk_register_queue(disk); - bdi = &disk->queue->backing_dev_info; - bdi_register_dev(bdi, disk_devt(disk)); retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj, "bdi"); WARN_ON(retval); |