From 70c8d6d632f886ef3a59cb9afa36f0af1df1a7eb Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 17 Mar 2017 19:57:15 +0530 Subject: [PATCH] block: Make del_gendisk() safer for disks without queues 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 Signed-off-by: Jan Kara Tested-by: Omar Sandoval Signed-off-by: Jens Axboe Git-commit: 90f16fddcc2802726142b8386c65ccb89f044613 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git Change-Id: I5ae377b2ace64d7a133979e656beb0eba45abc09 Signed-off-by: Ritesh Harjani --- block/genhd.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index dae7c9ed87e5..7f1e8f81ceb4 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -656,12 +656,16 @@ 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);