[PATCH] Btrfs: fix NULL pointer crash of deleting a seed device

[PATCH] Btrfs: fix NULL pointer crash of deleting a seed device

[Liu Bo]

Same as normal devices, seed devices should be initialized with
fs_info->dev_root as well, otherwise we'll get a NULL pointer crash.

Cc: Chris Murphy <lists@colorremedies.com>
Reported-by: Chris Murphy <lists@colorremedies.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
 fs/btrfs/volumes.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 49d7fab..bddf2bd 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6058,10 +6058,14 @@ void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 	struct btrfs_device *device;
 
-	mutex_lock(&fs_devices->device_list_mutex);
-	list_for_each_entry(device, &fs_devices->devices, dev_list)
-		device->dev_root = fs_info->dev_root;
-	mutex_unlock(&fs_devices->device_list_mutex);
+	while (fs_devices) {
+		mutex_lock(&fs_devices->device_list_mutex);
+		list_for_each_entry(device, &fs_devices->devices, dev_list)
+			device->dev_root = fs_info->dev_root;
+		mutex_unlock(&fs_devices->device_list_mutex);
+
+		fs_devices = fs_devices->seed;
+	}
 }
 
 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
-- 
1.8.1.4

Re: [PATCH] Btrfs: fix NULL pointer crash of deleting a seed device

[Anand Jain]

  Tested-by: Anand Jain <anand.jain@oracle.com>


On 11/05/14 23:14, Liu Bo wrote:
> Same as normal devices, seed devices should be initialized with
> fs_info->dev_root as well, otherwise we'll get a NULL pointer crash.
>
> Cc: Chris Murphy <lists@colorremedies.com>
> Reported-by: Chris Murphy <lists@colorremedies.com>
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> ---
>   fs/btrfs/volumes.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 49d7fab..bddf2bd 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -6058,10 +6058,14 @@ void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
>   	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
>   	struct btrfs_device *device;
>
> -	mutex_lock(&fs_devices->device_list_mutex);
> -	list_for_each_entry(device, &fs_devices->devices, dev_list)
> -		device->dev_root = fs_info->dev_root;
> -	mutex_unlock(&fs_devices->device_list_mutex);
> +	while (fs_devices) {
> +		mutex_lock(&fs_devices->device_list_mutex);
> +		list_for_each_entry(device, &fs_devices->devices, dev_list)
> +			device->dev_root = fs_info->dev_root;
> +		mutex_unlock(&fs_devices->device_list_mutex);
> +
> +		fs_devices = fs_devices->seed;
> +	}
>   }
>
>   static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
>