From: Theodore Ts'o <tytso@mit.edu>
Date: Tue, 28 Jul 2009 03:09:47 +0000 (-0400)
Subject: ext4: Avoid null pointer dereference when decoding EROFS w/o a journal
X-Git-Tag: v2.6.27.46~19
X-Git-Url: https://git.kernelconcepts.de/?a=commitdiff_plain;h=a3edfd184017a67b30080c1e0d46b91d7306b3d9;p=karo-tx-linux.git

ext4: Avoid null pointer dereference when decoding EROFS w/o a journal

commit 78f1ddbb498283c2445c11b0dfa666424c301803 upstream.

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>
---

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index db2642a927e9..baacaf8609fd 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -254,7 +254,8 @@ static const char *ext4_decode_error(struct super_block *sb, int errno,
 		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";