[PATCH 3/4] block: Make del_gendisk() safer for disks without queues
From: Jan Kara <jack@suse.cz>
Date: 2017-03-09 10:16:23
Also in:
linux-scsi
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
Commit 165a5e22fafb "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 <redacted> Tested-by: Omar Sandoval <redacted> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jan Kara <jack@suse.cz> --- block/genhd.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c
index b26a5ea115d0..94f323842b52 100644
--- a/block/genhd.c
+++ b/block/genhd.c@@ -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);
--
2.10.2