Commit 90f16fdd authored Mar 08, 2017 by Jan Kara Committed by Jens Axboe Mar 08, 2017

block: Make del_gendisk() safer for disks without queues



Commit 165a5e22 "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>

parent df23de55

block/genhd.c

+10 −6

Original line number	Diff line number	Diff line
		@@ -681,12 +681,16 @@ void del_gendisk(struct gendisk *disk)
		disk->flags &= ~GENHD_FL_UP;

		sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
		if (disk->queue) {
		/*
		* Unregister bdi before releasing device numbers (as they can get
		* reused and we'd get clashes in sysfs).
		* 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);