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SubjectRe: [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>
The patch looks fine. Acked-by: Jan Kara <jack@suse.cz>

Honza
> ---
> 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);
>
--
Jan Kara <jack@suse.cz>
SuSE CR Labs


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