Date: Mon, 15 Nov 2004 20:34:48 +0100 (CET) From: Sten Spans <sten@blinkenlights.nl> To: John Baldwin <jhb@FreeBSD.org> Cc: freebsd-alpha@FreeBSD.org Subject: Re: alpha and em mtu Message-ID: <Pine.SOC.4.61.0411152030030.29165@tea.blinkenlights.nl> In-Reply-To: <200411151111.11950.jhb@FreeBSD.org> References: <Pine.SOC.4.61.0411142153430.26307@tea.blinkenlights.nl> <200411151111.11950.jhb@FreeBSD.org>
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On Mon, 15 Nov 2004, John Baldwin wrote:
> On Sunday 14 November 2004 04:26 pm, Sten Spans wrote:
>> I upgraded my ds10 with an intel gigabit card,
>> and encountered the following issue (RELENG_5):
>>
>> deepthought# ifconfig em0 mtu 1501
>> deepthought#
>> fatal kernel trap:
>>
>> trap entry = 0x4 (unaligned access fault)
>> faulting va = 0xfffffc001847a02e
>> opcode = 0x28
>> register = 0x1
>> pc = 0xfffffc00004cd0f8
>> ra = 0xfffffc00004cce24
>> sp = 0xfffffe00187a9af0
>> curthread = 0xfffffc001f3a70e0
>> pid = 14, comm = swi1: net
>>
>> [thread 100006]
>> Stopped at tcp_input+0x368: srl t0,#0x2,t0 <t0=0x45>
>> db> trace
>> tcp_input() at tcp_input+0x368
>
> Can you do 'gdb kernel.debug' in your kernel build directory and then do 'l
> *tcp_input+0x368' to determine which source line it is panic'ing at? This
> might help us figure out what the unaligned access is so it can be fixed. If
> you don't have a debug kernel, please build one and reproduce the panic to
> get the updated 'tcp_input+0xblah' line and then do the gdb command with the
> updated 'tcp_input+0xblah' bit. Thanks.
Sure, I anticipated this, but couldn't quite
recall how to do the gdb magics :).
(gdb) l *tcp_input+0x368
0xfffffc00004cd0f8 is in tcp_input (/usr/src/sys/netinet/tcp_input.c:552).
547
548 /*
549 * Check that TCP offset makes sense,
550 * pull out TCP options and adjust length. XXX
551 */
552 off = th->th_off << 2;
553 if (off < sizeof (struct tcphdr) || off > tlen) {
554 tcpstat.tcps_rcvbadoff++;
555 goto drop;
556 }
The box that talks to the alpha has mtu 9014, this might
help to expose the bug.
--
Sten Spans
"There is a crack in everything, that's how the light gets in."
Leonard Cohen - Anthem
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