ubifs bad superblock bug

This patch fixes an issue when ubifs reads a bad superblock. Later it tries to free memory, that was not allocated, which freezes u-boot. This is fixed by looking for a non null pointer before free.

---
The message I got before u-boot freezes:
UBI: max/mean erase counter: 53/32
UBIFS: mounted UBI device 0, volume 1, name "rootfs"
UBIFS: mounted read-only
UBIFS: file system size: 49140 bytes (50319360 KiB, 0 MiB, 49140
LEBs)
UBIFS: journal size: 49 bytes (6838272 KiB, 0 MiB, 6678 LEBs)
UBIFS: media format: w4/r0 (latest is w4/r0)
UBIFS: default compressor: LZO
UBIFS: reserved for root: 0 bytes (0 KiB)
UBIFS error (pid 0): ubifs_read_node: bad node type (255 but expected
9)
UBIFS error (pid 0): ubifs_read_node: bad node at LEB 330:13104 UBIFS error (pid 0): ubifs_iget: failed to read inode 1, error -22 Error reading superblock on volume 'ubi:rootfs'!

Changes for v2:
- null has to be NULL

  fs/ubifs/super.c |    6 ++++--
  1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c index 63b2164..20fb244 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -848,8 +848,10 @@ void ubifs_umount(struct ubifs_info *c)
ubifs_debugging_exit(c);

/* Finally free U-Boot's global copy of superblock */
- free(ubifs_sb->s_fs_info);
- free(ubifs_sb);
+ if (ubifs_sb != NULL) {
+ free(ubifs_sb->s_fs_info);
+ free(ubifs_sb);
+ }
}

/**

 1.7.4.1

Hi Lars,

I had to manually apply this patch because it didn't apply clean.

Applied to u-boot-ubi/master. Thanks.

Best regards,
Stefan

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