From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: latest -git: A peculiar case of a stuck process
 (ext3/sched-related?)
Date: Fri, 18 Jul 2008 03:32:25 -0700
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	<19f34abd0807180317g40a218a2p2bb2857c6f5aa659@mail.gmail.com>
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Cc: linux-ext4@vger.kernel.org, sct@redhat.com, adilger@sun.com,
	"Ingo Molnar" <mingo@elte.hu>,
	"Peter Zijlstra" <a.p.zijlstra@chello.nl>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
To: "Vegard Nossum" <vegard.nossum@gmail.com>
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On Fri, 18 Jul 2008 12:17:17 +0200 "Vegard Nossum" <vegard.nossum@gmail.com> wrote:

> And the ext3_find_entry() corresponds to this line:
> 
>         for (; de < top; de = ext3_next_entry(de)) /* <--- HERE! */
>         if (ext3_match (namelen, name, de)) {
>                 if (!ext3_check_dir_entry("ext3_find_entry",
>                                           dir, de, bh,
>                           (block<<EXT3_BLOCK_SIZE_BITS(sb))
>                                   +((char *)de - bh->b_data))) {
>                         brelse (bh);
>                         *err = ERR_BAD_DX_DIR;
>                         goto errout;
>                 }
>                 *res_dir = de;
>                 dx_release (frames);
>                 return bh;
>         }
> 
> Is it possible that this loop can get stuck with a corrupt filesystem image?

yup.  ext2 did that a couple of times.  See the explicit check for
de->rec_len == 0 in ext2_find_entry().

We fixed one filesystem and forgot the others.  Again.