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Subject[PATCH 1/2] ext3: fix a bug accessing freed memory in ext3_abort
Hi Vegard,

Vegard Nossum wrote:

> commit 2d7c820e56ce83b23daee9eb5343730fb309418e
> Author: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
> Date: Wed Oct 22 14:15:01 2008 -0700
>
> ext3: add checks for errors from jbd
>
> introduces a regression which was discovered by kmemcheck:

Thank you for reporting this regression. It's my fault.
I send patches to fix.

Regards,


Subject: [PATCH 1/2] ext3: fix a bug accessing freed memory in ext3_abort

Vegard Nossum reported a bug which accesses freed memory. 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>
---
fs/ext3/super.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

Index: linux-2.6.28-rc2/fs/ext3/super.c
===================================================================
--- linux-2.6.28-rc2.orig/fs/ext3/super.c
+++ linux-2.6.28-rc2/fs/ext3/super.c
@@ -281,7 +281,8 @@ void ext3_abort (struct super_block * sb
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
{
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);





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