[126/146] UBIFS: fix a rare memory leak in ro to rw remounting path

[Greg KH]

2.6.38-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>

commit eaeee242c531cd4b0a4a46e8b5dd7ef504380c42 upstream.

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@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 fs/ubifs/sb.c    |    3 ++-
 fs/ubifs/super.c |    1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

--- 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)
 {
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1560,6 +1560,7 @@ static int ubifs_remount_rw(struct ubifs
 		}
 		sup->leb_cnt = cpu_to_le32(c->leb_cnt);
 		err = ubifs_write_sb_node(c, sup);
+		kfree(sup);
 		if (err)
 			goto out;
 	}


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