From owner-freebsd-bugs Mon Mar 18 7:23:39 2002
Delivered-To: freebsd-bugs@freebsd.org
Received: from mail.svzserv.kemerovo.su (mail.svzserv.kemerovo.su [213.184.65.66])
by hub.freebsd.org (Postfix) with ESMTP
id 5940337B988; Mon, 18 Mar 2002 07:21:29 -0800 (PST)
Received: from D00015.dialonly.kemerovo.su (www2.svzserv.kemerovo.su [213.184.65.86])
by mail.svzserv.kemerovo.su (8.11.6/8.11.6) with ESMTP id g2IFKct52918;
Mon, 18 Mar 2002 22:20:43 +0700 (NKZ)
(envelope-from eugen@d00015.dialonly.kemerovo.su)
Received: (from eugen@localhost)
by D00015.dialonly.kemerovo.su (8.11.6/8.11.6) id g2IFHtw00476;
Mon, 18 Mar 2002 22:17:55 +0700 (KRAT)
(envelope-from eugen)
Date: Mon, 18 Mar 2002 22:17:54 +0700
From: Eugene Grosbein <eugen@grosbein.pp.ru>
To: Matthew Dillon <dillon@apollo.backplane.com>
Cc: FreeBSD-gnats-submit@FreeBSD.ORG, freebsd-bugs@FreeBSD.ORG
Subject: Re: kern/35969: kernel option PPP_DEFLATE often procudes kernel panics; PPP_BSDCOMP sometimes procudes stalled connections
Message-ID: <20020318221754.A428@grosbein.pp.ru>
References: <200203160808.g2G880k17109@D00015.dialonly.kemerovo.su> <200203160820.g2G8K1s38158@freefall.freebsd.org> <20020317125834.A419@grosbein.pp.ru> <200203170647.g2H6lQ621576@apollo.backplane.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.2.5i
In-Reply-To: <200203170647.g2H6lQ621576@apollo.backplane.com>; from dillon@apollo.backplane.com on Sat, Mar 16, 2002 at 10:47:26PM -0800
Sender: owner-freebsd-bugs@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-bugs.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-bugs>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-bugs>
X-Loop: FreeBSD.org
On Sat, Mar 16, 2002 at 10:47:26PM -0800, Matthew Dillon wrote:
> :Now it does not panic.
> :So it's possible that last commit to src/sys/net/if_ppp.c broke something:
> :
> :revision 1.67.2.2
> :date: 2002/02/13 00:43:10; author: dillon; state: Exp; lines: +4 -3
> :MFC remove the MFREE() mbuf macro and cleanup twists in related code.
>
> Hmm. That change should not have made any difference, but it's easy
> to test... upgrade your system to 2002.02.13.00.50.00 (just after
> my commit) and see if the bug comes back. If it does I will run through
> that entire commit. I perused it just now and did not see anything
> specifically wrong.
I was wrong, your commit wasn't the cause of the panics.
Now I believe I've isolated the moment of breakage.
The system updated (or downgraded) to tag=RELENG_4 date=2002.02.22.00.00.00
does not panic using PPP_DEFLATE but suffers from stalled connections.
One have to send USR2 to pppd to revive PPP link.
man pppd says:
SIGUSR2
This signal causes pppd to renegotiate compression.
This can be useful to re-enable compression after
it has been disabled as a result of a fatal decom-
pression error. (Fatal decompression errors gener-
ally indicate a bug in one or other implementa-
tion.)
The system updated to tag=RELENG_4 date=2002.02.22.03.00.00
quickly panics if PPP_DEFLATE is used. It seems it panics due to
corrupted kernel area.
There was the only commit to RELENG_4 during this period,
it patched src/lib/libz/infblock.c and src/sys/net/zlib.c
The latter file is used by kernel ppp driver.
I'd like to investigate this further but I'm definitly not a kernel hacker.
The only workaround I've found is using 'nodeflate' option of pppd.
This effectivly disables usage of deflate compression and eliminates panics
even for kernel built from sources after 2002.02.22.03.00.00
Eugene Grosbein
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-bugs" in the body of the message