From: Zheng Liu <gnehzuil.liu@gmail.com>
To: Theodore Ts'o <tytso@mit.edu>, Hugh Dickins <hughd@google.com>,
Zheng Liu <wenqing.lz@taobao.com>,
Yongqiang Yang <xiaoqiangnk@gmail.com>,
Allison Henderson <achender@linux.vnet.ibm.com>,
Lukas Czerner <lczerner@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH next/mmotm] ext4: fix cache_es after merge_left
Date: Fri, 28 Sep 2012 06:53:57 +0800 [thread overview]
Message-ID: <20120927225357.GA19675@gmail.com> (raw)
In-Reply-To: <20120927203920.GB9585@thunk.org>
On Thu, Sep 27, 2012 at 04:39:20PM -0400, Theodore Ts'o wrote:
> On Thu, Sep 27, 2012 at 01:31:28PM -0700, Hugh Dickins wrote:
> > Kernel build with CONFIG_DEBUG_SLAB or CONFIG_SLUB_DEBUG slub_debug=FPZ
> > gives me kernel BUG at fs/ext4/extents_status.c:142! That's the
> > BUG_ON(es->start + es->len < es->start) in extent_status_end() called
> > from ext4_es_insert_extent(). tree->cache_es has been freed and poisoned.
> >
> > This comes from when ext4_es_try_to_merge_left() merges es into leftward
> > es1, but ext4_es_insert_extent()'s out then updates cache_es to the freed
> > extent_status. ext4_es_try_to_merge_right() does not pose a problem.
> >
> > Change ext4_es_try_to_merge_left() to return whichever extent_status
> > should be recorded in tree->cache_es. Remove cache_es update from
> > both of them, leaving that to ext4_es_insert_extent()'s out label.
> >
> > Signed-off-by: Hugh Dickins <hughd@google.com>
>
> Hugh, thanks for finding this bug!
>
> Zheng, you were going to send me an updated patch series; can you take
> care of merging this patch into your patch series (and crediting Hugh
> with a Signed-off-by as appropriate)?
Yeah, thanks for fixing it, although I have fixed this problem in my new
patch set. I will add a Signed-off-by into the patch.
Regards,
Zheng
prev parent reply other threads:[~2012-09-27 22:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-27 20:31 [PATCH next/mmotm] ext4: fix cache_es after merge_left Hugh Dickins
2012-09-27 20:39 ` Theodore Ts'o
2012-09-27 22:53 ` Zheng Liu [this message]
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