From owner-freebsd-current Fri Dec 8 09:09:15 1995 Return-Path: owner-current Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id JAA18698 for current-outgoing; Fri, 8 Dec 1995 09:09:15 -0800 (PST) Received: from halloran-eldar.lcs.mit.edu (halloran-eldar.lcs.mit.edu [18.26.0.159]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id JAA18692 for ; Fri, 8 Dec 1995 09:09:11 -0800 (PST) Received: by halloran-eldar.lcs.mit.edu; (5.65/1.1.8.2/19Aug95-0530PM) id AA15017; Fri, 8 Dec 1995 12:09:03 -0500 Date: Fri, 8 Dec 1995 12:09:03 -0500 From: "Garrett A. Wollman" Message-Id: <9512081709.AA15017@halloran-eldar.lcs.mit.edu> To: mark@linus.demon.co.uk (Mark Valentine) Cc: freebsd-current@freebsd.org Subject: Re: integer divide fault in tcp_timers() - update In-Reply-To: <199512072310.XAA00807@linus.demon.co.uk> References: <199512072310.XAA00807@linus.demon.co.uk> Sender: owner-current@freebsd.org Precedence: bulk < I ran tcpdump, and on two runs I noticed that just before the panic, > I'm sending out several duplicate acks in quick succession (within > milliseconds of each other). I append the tail end of what tcpdump > managed to get to the disk before the crash, in case the prior > context is useful, but what I'm seeing immediately before before the > crash are transmitted packets of the form: ". ack 356 win 16384 (DF)", > the same sequence number each time, a short burst of those, maybe one > other packet logged on the console after those, and then it blows. You might try compiling ip_icmp.c with the newly-added DEBUG_MTUDISC (I think that's what I called it) option, to see what (if anything) the ICMP side of the MTU discovery code is doing. If we can narrow down the cause somewhat, it would be of value. A traceback might also be interesting. -GAWollman -- Garrett A. Wollman | Shashish is simple, it's discreet, it's brief. ... wollman@lcs.mit.edu | Shashish is the bonding of hearts in spite of distance. Opinions not those of| It is a bond more powerful than absence. We like people MIT, LCS, ANA, or NSA| who like Shashish. - Claude McKenzie + Florent Vollant