UBIFS: fix a rare memory leak in ro to rw remounting path

When re-mounting from R/O mode to R/W mode and the LEB count in the superblock
is not up-to date, because for the underlying UBI volume became larger, we
re-write the superblock. We allocate RAM for these purposes, but never free it.
So this is a memory leak, although very rare one.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org

2 files changed, 3 insertions, 1 deletions

diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
index bf31b4729e51..cad60b51f7c4 100644
--- a/fs/ubifs/sb.c
+++ b/fs/ubifs/sb.c
@@ -475,7 +475,8 @@ failed:
  * @c: UBIFS file-system description object
  *
  * This function returns a pointer to the superblock node or a negative error
- * code.
+ * code. Note, the user of this function is responsible of kfree()'ing the
+ * returned superblock buffer.
  */
 struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
 {
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 407c064fb1c1..575ea8353d08 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1585,6 +1585,7 @@ static int ubifs_remount_rw(struct ubifs_info *c)
                 }
                 sup->leb_cnt = cpu_to_le32(c->leb_cnt);
                 err = ubifs_write_sb_node(c, sup);
+                kfree(sup);
                 if (err)
                         goto out;
         }