Hi Liu, (2014/08/12 6:41), Chris Murphy wrote:
On Jul 29, 2014, at 5:09 AM, Liu Bo <bo.li.liu@xxxxxxxxxx> wrote:Commit 49c6f736f34f901117c20960ebd7d5e60f12fcac( btrfs: dev replace should replace the sysfs entry) added the missing sysfs entry in the process of device replace, but didn't take missing devices into account, so now we have BUG: unable to handle kernel NULL pointer dereference at 0000000000000088 IP: [<ffffffffa0268551>] btrfs_kobj_rm_device+0x21/0x40 [btrfs] ... To reproduce it, 1. mkfs.btrfs -f disk1 disk2 2. mkfs.ext4 disk1 3. mount disk2 /mnt -odegraded 4. btrfs replace start -B 1 disk3 /mnt -------------------------- This fixes the problem. Reported-by: Chris Murphy <lists@xxxxxxxxxxxxxxxxx> Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx> --- fs/btrfs/sysfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 7869936..12e5355 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -614,7 +614,7 @@ int btrfs_kobj_rm_device(struct btrfs_fs_info *fs_info, if (!fs_info->device_dir_kobj) return -EINVAL; - if (one_device) { + if (one_device && one_device->bdev) { disk = one_device->bdev->bd_part; disk_kobj = &part_to_dev(disk)->kobj;Applied to 3.16.0 and tested, problem is fixed. Chris Murphy
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@xxxxxxxxxxxxxx> Tested-by: Satoru Takeuchi <takeuchi_satoru@xxxxxxxxxxxxxx> I confirmed both - This problem happens with 3.16, and - This problem doesn't happen with 3.16 + your patch. Thanks, Satoru
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