freebsd stable - Jan 2015 - 10.1-STABLE/i386 GENERIC + VIMAGE: Panic when going multiuser

On Mon, Jan 5, 2015 at 2:23 PM, <sthaug at nethelp.no> wrote:
> > Thanks for providing the detailed logs.  It looks like there is
something
> > IPv6 related in your setup that is triggering this
> > problem.  I don't have IPv6 configured on any of my boxes.
> > Can you provide your /etc/rc.conf, and any other relevant configs
which
> > trigger usage of IPv6?
>
> Unfortunately, there is *no* IPv6 config on the box (aside from what
> might be done by default). rc.conf:
>
> hostname="verdi.nethelp.no"
> keymap="norwegian.iso.kbd"
> ifconfig_bge1="inet 10.0.0.2 netmask 255.255.255.252"
> sshd_enable="YES"
> dumpdev="AUTO"
> ddb_enable="YES"
> background_fsck="NO"
>

That config is minimal, so I don't see anything offhand which would trigger
IPv6.
But there could be something else running on the system that triggers it.

Do you have *any* kernel modules which are installed on the system and not
built as part of the buildworld/buildkernel process?  For example, kernel
modules
installed via a port?

Lastly, since your crash is triggered by "sysctl -a" with VIMAGE and
DDB
added to a GENERIC kernel config in 10.1,
can you see the last sysctl which is printed out before the panic occurs?

--
Craig

> > Unfortunately, there is *no* IPv6 config on the box (aside from what
> > might be done by default). rc.conf:
> >
> > hostname="verdi.nethelp.no"
> > keymap="norwegian.iso.kbd"
> > ifconfig_bge1="inet 10.0.0.2 netmask 255.255.255.252"
> > sshd_enable="YES"
> > dumpdev="AUTO"
> > ddb_enable="YES"
> > background_fsck="NO"
> >
> 
> 
> That config is minimal, so I don't see anything offhand which would
trigger
> IPv6.
> But there could be something else running on the system that triggers it.
> 
> Do you have *any* kernel modules which are installed on the system and not
> built as part of the buildworld/buildkernel process?  For example, kernel
> modules
> installed via a port?
No modules.
> Lastly, since your crash is triggered by "sysctl -a" with VIMAGE
and DDB
> added to a GENERIC kernel config in 10.1,
> can you see the last sysctl which is printed out before the panic occurs?
I have done a bit more testing with sysctl. There are two specific
sysctls which trigger the panic:

net.inet6.ip6.temppltime
net.inet6.ip6.tempvltime

All the other sysctls are fine, no panic generated.

What can I do to help debug this further? The box where this happens
isn't doing anything else useful at the moment, so can be crashed at
will :-)

Steinar Haug, Nethelp consulting, sthaug at nethelp.no