From: David Sterba <dsterba@suse.com>
Date: Tue, 26 Apr 2016 14:03:57 +0000 (+0200)
Subject: btrfs: add check to sysfs handler of label
X-Git-Tag: v4.9.8~1839^2~15^2~3^2~17
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=66ac9fe7bacf9fa76c472efc7a7aaa590c7bce6a;p=platform%2Fkernel%2Flinux-rpi3.git

btrfs: add check to sysfs handler of label

Add a sanity check for the fs_info as we will dereference it, similar to
what the 'store features' handler does.

Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 6a6bb60..3d14618 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -377,6 +377,9 @@ static ssize_t btrfs_label_store(struct kobject *kobj,
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 	size_t p_len;
 
+	if (!fs_info)
+		return -EPERM;
+
 	if (fs_info->sb->s_flags & MS_RDONLY)
 		return -EROFS;