From 4d7c1d3fd7c7eda7dea351f071945e843a46c145 Mon Sep 17 00:00:00 2001 From: zhengbin Date: Wed, 20 Feb 2019 21:27:05 +0800 Subject: block: fix NULL pointer dereference in register_disk 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 Signed-off-by: Jens Axboe --- block/genhd.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'block') diff --git a/block/genhd.c b/block/genhd.c index 1dd8fd6613b8..78b82d26aa9c 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -655,10 +655,12 @@ exit: 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); + } } /** -- cgit