FreeBSD-6.2, SMP, coredump -- fatal trap 12 : page fault while in kernel mode, current process: (swi1:net)

[Yong Rao]

Hi Kris,

We are wondering if there is any connection between the core dump
failure and the options DEVICE_POLLING? In our kernel, we have options
DEVICE_POLLING, and in our driver (Ethernet) we have the
ether_poll_register() function (not registered yet). Do you know if
there is any problem with this? (Using polling mode and SMP
simultaneously)

Thanks,
Yong


-----Original Message-----
From: Kris Kennaway [mailto:kris at obsecurity.org] 
Sent: Thursday, June 14, 2007 12:06 PM
To: Yong Rao
Cc: Kris Kennaway; freebsd-smp at freebsd.org; Jagjit Choudhary
Subject: Re: FreeBSD-6.2, SMP, coredump -- fatal trap 12 : page fault
while in kernel mode, current process: (swi1:net)

On Wed, Jun 13, 2007 at 11:21:53PM -0700, Yong Rao wrote:
> Hi Kris,
> 
> Thanks for your reply.
> 
> I have 2 exactly the same equipments. The ONLY difference is the OS.
One
> is running 6.0 FBSD. The other one is 6.2 FBSD. 
> 
> I built the kernels using the same configuration file (with SMP
option).
> My problem is that the OS 6.2 does not dump core when crash happens,
> while the OS 6.0 does core dump perfectly. Why it is like this?
> Something wrong with FBSD 6.2 OS when SMP options is enabled?

Impossible to rule it out of course, but this sounds unlikely.  Many
of us developers perform dumps on SMP 6.2 systems regularly.  There
were *many* changes between 6.0 and 6.2, and perhaps it is as simple
as your workload is exercising a slightly different code path or
timing.  Using DDB you will be able to determine what the other
threads are doing at the time of crash and this should help to figure
out why dumping is failing.

Kris