From: zhengbin <zhengbin13@xxxxxxxxxx> If __device_add_disk-->bdi_register_owner-->bdi_register--> bdi_register_va-->device_create_vargs fails, bdi->dev is still NULL, __device_add_disk-->register_disk will visit bdi->dev->kobj. This patch fixes that. Signed-off-by: zhengbin <zhengbin13@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> (cherry picked from commit 4d7c1d3fd7c7eda7dea351f071945e843a46c145) Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxx> --- block/genhd.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index 2b536ab570ac..6965dde96373 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -652,10 +652,12 @@ static void register_disk(struct device *parent, struct gendisk *disk) kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD); disk_part_iter_exit(&piter); - err = sysfs_create_link(&ddev->kobj, - &disk->queue->backing_dev_info->dev->kobj, - "bdi"); - WARN_ON(err); + if (disk->queue->backing_dev_info->dev) { + err = sysfs_create_link(&ddev->kobj, + &disk->queue->backing_dev_info->dev->kobj, + "bdi"); + WARN_ON(err); + } } /** -- 2.25.1