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block: Make del_gendisk() safer for disks without queues

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Commit 165a5e22fa "block: Move bdi_unregister() to del_gendisk()"
added disk->queue dereference to del_gendisk(). Although del_gendisk()
is not supposed to be called without disk->queue valid and
blk_unregister_queue() warns in that case, this change will make it oops
instead. Return to the old more robust behavior of just warning when
del_gendisk() gets called for gendisk with disk->queue being NULL.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Tested-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Jan Kara 2017-03-08 17:48:33 +01:00 committed by Jens Axboe
parent df23de5561
commit 90f16fddcc
1 changed files with 10 additions and 6 deletions
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16
block/genhd.c
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@ -681,12 +681,16 @@ void del_gendisk(struct gendisk *disk)
disk->flags &= ~GENHD_FL_UP;
sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
/*
* Unregister bdi before releasing device numbers (as they can get
* reused and we'd get clashes in sysfs).
*/
bdi_unregister(disk->queue->backing_dev_info);
blk_unregister_queue(disk);
if (disk->queue) {
/*
* Unregister bdi before releasing device numbers (as they can
* get reused and we'd get clashes in sysfs).
*/
bdi_unregister(disk->queue->backing_dev_info);
blk_unregister_queue(disk);
} else {
WARN_ON(1);
}
blk_unregister_region(disk_devt(disk), disk->minors);
part_stat_set_all(&disk->part0, 0);