ext3: fix a bug accessing freed memory in ext3_abort

Vegard Nossum reported a bug which accesses freed memory (found via
kmemcheck).  When journal has been aborted, ext3_put_super() calls
ext3_abort() after freeing the journal_t object, and then ext3_abort()
accesses it.  This patch fix it.

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 18eaa78..e5717a4 100644 (file)
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -281,7 +281,8 @@ void ext3_abort (struct super_block * sb, const char * function,
        EXT3_SB(sb)->s_mount_state |= EXT3_ERROR_FS;
        sb->s_flags |= MS_RDONLY;
        EXT3_SB(sb)->s_mount_opt |= EXT3_MOUNT_ABORT;
-       journal_abort(EXT3_SB(sb)->s_journal, -EIO);
+       if (EXT3_SB(sb)->s_journal)
+               journal_abort(EXT3_SB(sb)->s_journal, -EIO);
 }
 
 void ext3_warning (struct super_block * sb, const char * function,
@@ -390,11 +391,14 @@ static void ext3_put_super (struct super_block * sb)
 {
        struct ext3_sb_info *sbi = EXT3_SB(sb);
        struct ext3_super_block *es = sbi->s_es;
-       int i;
+       int i, err;
 
        ext3_xattr_put_super(sb);
-       if (journal_destroy(sbi->s_journal) < 0)
+       err = journal_destroy(sbi->s_journal);
+       sbi->s_journal = NULL;
+       if (err < 0)
                ext3_abort(sb, __func__, "Couldn't clean up the journal");
+
        if (!(sb->s_flags & MS_RDONLY)) {
                EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
                es->s_state = cpu_to_le16(sbi->s_mount_state);