Date: Fri, 17 Aug 2001 15:25:40 -0700 (PDT) From: John Baldwin <jhb@FreeBSD.org> To: "David O'Brien" <obrien@FreeBSD.org> Cc: alpha@FreeBSD.org Subject: Re: today's kernel + JHB's trap.c patch is *evil* Message-ID: <XFMail.010817152540.jhb@FreeBSD.org> In-Reply-To: <20010816215234.A5722@dragon.nuxi.com>
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On 17-Aug-01 David O'Brien wrote:
> On Thu, Aug 16, 2001 at 04:29:27PM -0700, John Baldwin wrote:
>> > Mounting root from ufs:/dev/da0a
>> > SMP: AP CPU #1 Launched!
>> >
>> > fatal kernel trap:
>> >
>> > trap entry = 0x2 (memory management fault)
>> > cpuid = 0
>> > faulting va = 0x0
>>
>> NULL pointer deref.
>>
>> > type = access violation
>> > cause = load instructon
>> > pc = 0xfffffc00003c3814
>>
>> Do you have a debug kernel? If so, can you do 'gdb -k kernel.debug' and
>> then
>> do 'l *0xfffffc00003c3814'?
>
> 0xfffffc00003c3814 is in _mtx_unlock_sleep
> (../../../kern/kern_mutex.c:492).
> 487
> 488 p1 = TAILQ_FIRST(&m->mtx_blocked);
> 489 MPASS(p->p_magic == P_MAGIC);
> 490 MPASS(p1->p_magic == P_MAGIC);
> 491
> 492 TAILQ_REMOVE(&m->mtx_blocked, p1, p_procq);
> 493
> 494 if (TAILQ_EMPTY(&m->mtx_blocked)) {
> 495 LIST_REMOVE(m, mtx_contested);
> 496 _release_lock_quick(m);
Umm, ok. I'll have to try and reproduce this locally. The mutex claims to be
contested but has no processes in its list of blocked processes.
--
John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/
PGP Key: http://www.baldwin.cx/~john/pgpkey.asc
"Power Users Use the Power to Serve!" - http://www.FreeBSD.org/
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