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authorAnand Jain <Anand.Jain@oracle.com>2014-01-15 17:22:28 +0800
committerChris Mason <clm@fb.com>2014-02-15 08:03:09 -0800
commitf085381e6d08f4c8d6882825f31accd455c54d70 (patch)
treea2288e14def975689e3f32c9960c9a0f68aa6d19
parent3a0dfa6a12e4bb64a434426ecb17d4842092db5e (diff)
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btrfs: fix null pointer deference at btrfs_sysfs_add_one+0x105
bdev is null when disk has disappeared and mounted with the degrade option stack trace --------- btrfs_sysfs_add_one+0x105/0x1c0 [btrfs] open_ctree+0x15f3/0x1fe0 [btrfs] btrfs_mount+0x5db/0x790 [btrfs] ? alloc_pages_current+0xa4/0x160 mount_fs+0x34/0x1b0 vfs_kern_mount+0x62/0xf0 do_mount+0x22e/0xa80 ? __get_free_pages+0x9/0x40 ? copy_mount_options+0x31/0x170 SyS_mount+0x7e/0xc0 system_call_fastpath+0x16/0x1b --------- reproducer: ------- mkfs.btrfs -draid1 -mraid1 /dev/sdc /dev/sdd (detach a disk) devmgt detach /dev/sdc [1] mount -o degrade /dev/sdd /btrfs ------- [1] github.com/anajain/devmgt.git Signed-off-by: Anand Jain <Anand.Jain@oracle.com> Tested-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
-rw-r--r--fs/btrfs/sysfs.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 782374d8fd19..865f4cf9a769 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -578,8 +578,14 @@ static int add_device_membership(struct btrfs_fs_info *fs_info)
return -ENOMEM;
list_for_each_entry(dev, &fs_devices->devices, dev_list) {
- struct hd_struct *disk = dev->bdev->bd_part;
- struct kobject *disk_kobj = &part_to_dev(disk)->kobj;
+ struct hd_struct *disk;
+ struct kobject *disk_kobj;
+
+ if (!dev->bdev)
+ continue;
+
+ disk = dev->bdev->bd_part;
+ disk_kobj = &part_to_dev(disk)->kobj;
error = sysfs_create_link(fs_info->device_dir_kobj,
disk_kobj, disk_kobj->name);