[02/90] ext4: Avoid null pointer dereference when decoding EROFS w/o a journal

Greg KH
2009-12-11T04:36:17Z

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

------------------
(cherry picked from commit 78f1ddbb498283c2445c11b0dfa666424c301803)

We need to check to make sure a journal is present before checking the
journal flags in ext4_decode_error().

Signed-off-by: Eric Sesterhenn <eric.sesterhenn@lsexperts.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
fs/ext4/super.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -344,7 +344,8 @@ static const char *ext4_decode_error(str
errstr = "Out of memory";
break;
case -EROFS:
- if (!sb || EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT)
+ if (!sb || (EXT4_SB(sb)->s_journal &&
+ EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT))
errstr = "Journal has aborted";
else
errstr = "Readonly filesystem";