Re: [PATCH] btrfs: oops in device_list_add()

[Anand Jain]

On 1/27/19 12:58 PM, Al Viro wrote:

        alloc_fs_devices() can return ERR_PTR(-ENOMEM), so
dereferencing its result before the check for IS_ERR() is
a bad idea...

Fixes: d1a63002829a4
Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>

 nice catch.
 Reviewed-by: Anand Jain <anand.j...@oracle.com>

---
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 85149f27644d..72adc5643bde 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -955,11 +955,11 @@ static noinline struct btrfs_device 
*device_list_add(const char *path,
                else
                        fs_devices = alloc_fs_devices(disk_super->fsid, NULL);

- fs_devices->fsid_change = fsid_change_in_progress;

-
                if (IS_ERR(fs_devices))
                        return ERR_CAST(fs_devices);

+ fs_devices->fsid_change = fsid_change_in_progress;

+
                mutex_lock(&fs_devices->device_list_mutex);
                list_add(&fs_devices->fs_list, &fs_uuids);