Re: Panic in _mtx_lock_flags+0x40

On 23-May-2003 Jun Kuriyama wrote:
> At Thu, 22 May 2003 16:35:33 +0000 (UTC),
> John Baldwin wrote:
>> > db> trace
>> > _mtx_lock_flags(0,0,c0401b81,11d,e11edb18) at _mtx_lock_flags+0x40
>> 
>> Trying to lock a NULL pointer is definitely going to panic, yes.
>> I'm curious what vm_fault() line you are at.
>> 
>> > vm_fault(c082f000,deadc000,1,0,c3affab0) at vm_fault+0x2cc
>> > trap_pfault(e11edc10,0,deadc0de,cf74d400,deadc0de) at trap_pfault+0x161
>> > trap(c0410018,10,c03e0010,c7a73c9c,c7e8f600) at trap+0x3ad
>> > calltrap() at calltrap+0x5
>> > --- trap 0xc, eip = 0xc015c580, esp = 0xe11edc50, ebp = 0xe11edc68 ---
>> > ad_detach(c7a73c9c,ffffffff,c03d5de3,0,1) at ad_detach+0x40
>> 
>> The real bug is probably here, probably a NULL pointer dereference.
>> I would use gdb to figure out what this file:line is and send the
>> report to Søren.
>> 
>> > ata_reinit(c7a73c00,cacf5100,c03d1747,0,0) at ata_reinit+0x9b
>> > ad_timeout(cacf5100,0,c03ec2fe,bf,4feaef) at ad_timeout+0x136
>> > softclock(0,0,c03e9271,233,c3afe780) at softclock+0x19c
>> > ithread_loop(c3afd200,e11edd48,c03e9122,2f8,0) at ithread_loop+0x182
>> > fork_exit(c021bab0,c3afd200,e11edd48) at fork_exit+0xc0
>> > fork_trampoline() at fork_trampoline+0x1a
>> > --- trap 0x1, eip = 0, esp = 0xe11edd7c, ebp = 0 ---
> 
> Is this help you?
> 
> (kgdb) l *ad_detach+0x40
> 0xc015c580 is in ad_detach (../../../dev/ata/ata-disk.c:218).
> 213     
> 214         atadev->flags |= ATA_D_DETACHING;
> 215         ata_prtdev(atadev, "removed from configuration\n");
> 216         ad_invalidatequeue(adp, NULL);
> 217         TAILQ_FOREACH(request, &atadev->channel->ata_queue, chain) {
> 218             if (request->softc != adp)
> 219                 continue;

Likely 'request' is NULL here.  That seems odd though.

> 220             TAILQ_REMOVE(&atadev->channel->ata_queue, request, chain);
> 221             biofinish(request->bp, NULL, ENXIO);
> 222             ad_free(request);

-- 

John Baldwin <jhb_at_FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/