From: Ray Van Dolson <rayvd@digitalpath.net>
To: Matt Domsch <Matt_Domsch@dell.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Unable to handle kernel NULL pointer dereference at virtual address 00000000
Date: Mon, 3 Jan 2005 09:22:22 -0800 [thread overview]
Message-ID: <20050103172222.GA13804@digitalpath.net> (raw)
In-Reply-To: <20041215162943.GB31494@lists.us.dell.com>
On Wed, Dec 15, 2004 at 10:29:43AM -0600, Matt Domsch wrote:
> > ksymoops output of problem:
> > Unable to handle kernel NULL pointer dereference
> > 00000000
> > *pde = 00000000
> > Oops: 0000 [#1]
> > CPU: 2
> > EIP: 0060:[<00000000>] Not tainted VLI
> > Using defaults from ksymoops -t elf32-i386 -a i386
> > EFLAGS: 00010286 (2.6.9)
> > eax: ed13b000 ebx: d1d0a000 ecx: c029e9de edx: f795ef40
> > esi: d1d0a000 edi: 00000000 ebp: e2f30080 esp: d2b0dea0
> > ds: 007b es: 007b ss: 0068
> > Stack: c02a205a ed13b000 00000000 c02a122c d1d0a000 13208a2e c040956f
> > d1d0a000 d1d0a00c e2f30080 00000000 c029cda9 d1d0a000 e2f30080 00000000
> > c01552cd e2f30080 00000010 00000004 00000004 c0166aa0 e2f30080 00000000
> > 00000000
> > Call Trace: [<c02a205a>] pty_chars_in_buffer+0x2c/0x49 [<c02a122c>]
> > normal_poll+0xed/0x150 [<c040956f>] schedule_timeout+0x75/0xbf
> > [<c029cda9>] tty_poll+0xa0/0xb0 [<c01552cd>] fget+0x49/0x5e [<c0166aa0>]
> > do_select+0x269/0x2c6 [<c0166691>] __pollwait+0x0/0xc7 [<c0166dd5>]
> > sys_select+0x2b3/0x4c6 [<c0105971>] sysenter_past_esp+0x52/0x71
> > Code: Bad EIP value.
> It looks like pty_chars_in_buffer() dereferenced a NULL function
> pointer, but I don't see how that can be, the one deference is tested
> for NULL before doing so.
>
> I can't rule out the ppp_mppe code, but I haven't seen this crash
> before myself. Does this happen on simlar systems that aren't running poptop?
>
> Thanks,
> Matt
Yet another follow-up on this. After completely disabling SMP/Hyperthreading
on these systems, we have had zero NULL pointer dereferences. Obviously can't
say for sure that this points to problems with the MPPE module--the only true
test would be to allow our customers to connect without MPPE and reenable
SMP/HT. Obviously not an option in a live environment. :)
Guess we just won't be using SMP/HT on our busier systems!
Ray
prev parent reply other threads:[~2005-01-03 17:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-15 1:32 Unable to handle kernel NULL pointer dereference at virtual address 00000000 Ray Van Dolson
2004-12-15 16:29 ` Matt Domsch
2004-12-15 16:36 ` Ray Van Dolson
2004-12-17 16:11 ` Ray Van Dolson
2005-01-03 17:22 ` Ray Van Dolson [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20050103172222.GA13804@digitalpath.net \
--to=rayvd@digitalpath.net \
--cc=Matt_Domsch@dell.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox