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authorSigned-off-by: Jan Kara <jack@suse.cz>2010-09-16 20:36:36 +0200
committerJens Axboe <jaxboe@fusionio.com>2010-09-16 20:36:36 +0200
commit01ea50638bc04ca5259f5711fcdedefcdde1cf43 (patch)
treec525dc13b05feab90d71b78a1d7adb0ddde081ea /block
parent2786c4e5e54802c34297e55050fef3e862a27b3f (diff)
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block: Fix race during disk initialization
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 Cc: stable@kernel.org Reported-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block')
-rw-r--r--block/genhd.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 5c9c503de42..7923e720ddf 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);