Re: double fault when using fssconfig + repetitive savecore problem

[Juergen Hannken-Illjes <hannken%eis.cs.tu-bs.de@localhost>]

On Sun, Feb 20, 2011 at 03:55:08PM +0100, theo borm wrote:
> Hi,
> 
> First of all, thank you for the hint. Savecore -c worked like a charm. 
> I've also taken your suggestion, and generated a kernel with debugging 
> (without re0). In short, this does not change anything so I still have 
> no coredump to debug (see point 3 and 4 below)
> 
> Second, it appears as if the problems are related to the fact that I was 
> running NetBSD in a (KVM) virtual machine. On real hardware (which took 
> some time to get, hence my late response), it's simply gone.
> 
> 
> Now, having said that, I'm still very interested in running NetBSD from 
> KVM (not Xen for other reasons).
> 
> 
> Running NetBSD (ffv1 / and /tmp) from a KVM (with bridged network 
> configuration) now causes me serious trouble:
> 
> 1) (Unrelated) The virtual re* network interface has "re0: watchdog 
> timeout" problems. A workaround seems to be compiling a kernel without 
> "re*", which causes the rtk* driver to attach to the interface. This 
> works mostly, however, I am now seeing occasional "rtk0: watchdog 
> timeout" messages, after which the network becomes unusable, and I have 
> also been able to trigger a kernel crash by (putatively) external 
> network traffic and an unresponsive external NFS server (NetBSD crashed 
> within seconds of the external NFS server, having mounted only a 
> non-system directory).
> 
> 2) fssconfig immediately causes a kernel crash and core dump. This is 
> unrelated to my removal of the re* driver, because I get the same 
> problem with a stock GENERIC kernel.
> 
> 3) <ctrl>-<alt>-<escape>, followed by "sync" generates a memory dump. 
> After this memory dump I'm back in the same repetitive core-saving 
> cycle, and I have to "savecore -c" again.
> 
> 4) savecore (during reboot) fails with an "savecore: (null): Bad 
> address", and while I end up with a "netbsd.N.core.gz", the accompanying 
> "netbsd.N.gz" file is simply empty. My suspicion is that this is what is 
> causing 3) to happen.

Try adding

        savecore=YES            savecore_flags="-z -N /netbsd"

to /etc/rc.conf.  A working crash dump would help with 2) too.

-- 
Juergen Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig 
(Germany)