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Message-ID: <4A5A46ED.7010907@gmail.com>
Date: Sun, 12 Jul 2009 22:26:21 +0200
From: Jiri Slaby <jirislaby@gmail.com>
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To: Parag Warudkar <parag.warudkar@gmail.com>
CC: linux-kernel@vger.kernel.org, thomas@m3y3r.de, sds@tycho.nsa.gov,
       jmorris@namei.org, eparis@parisplace.org
Subject: Re: 2.6.31-rc2: BUG: unable to handle kernel NULL pointer dereference
References: <1247410030.1095.1.camel@localhost> <loom.20090712T172408-520@post.gmane.org>
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On 07/12/2009 07:30 PM, Parag Warudkar wrote:
> static void selinux_write_opts(struct seq_file *m,
> 1012                                struct security_mnt_opts *opts)
> 1013 {
> 1014         int i;
> 1015         char *prefix;
> 1016
> 1017         for (i = 0; i < opts->num_mnt_opts; i++) {
> 1018                 char *has_comma;
> 1019
> 1020                 if (opts->mnt_opts[i])
> 1021                         has_comma = strchr(opts->mnt_opts[i], ',');
>                                          ^^^^^^^^^^^^^^^^^^^^^^^^^
> And that is a NULL pointer dereference - but we just checked for
> opts->mnt_opts[i] for not NULL. 

Note, that there is not a NULL dereference. It dereferences 0x40 which
came in as %rdi. Looks like somebody assigned garbage in there.

Or a single bit mem error. Is memtest OK with this machine?

What warning tainted the kernel before this oops is still interesting...
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