ext4: error proc entry creation when the fs/ext4 is not correctly created

When the directory fs/ext4 is not correctly created under proc, the entry
under this directory should not be created.

Signed-off-by: Shen Feng <shen@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 21ee6d42ee7b..771a1d608528 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2661,6 +2661,10 @@ static int ext4_mb_init_per_dev_proc(struct super_block *sb)
         struct proc_dir_entry *proc;
         char devname[64];
 
+        if (proc_root_ext4 == NULL) {
+                sbi->s_mb_proc = NULL;
+                return -EINVAL;
+        }
         bdevname(sb->s_bdev, devname);
         sbi->s_mb_proc = proc_mkdir(devname, proc_root_ext4);