savecore writes files after every reboot

[Fredrik Pettai <pettai%nordu.net@localhost>]

Hi,

During reboots (shutdown -r now) on a particular machine, I've started to see 
this during boot:

Jun 13 10:06:39 netbsd-vm savecore: warning: (null) version mismatch:        
NetBSD 5.1 (GENERIC) #0: Sun Nov  7 14:39:56 UTC 2010   
builds%b6.netbsd.org@localhost:/home/builds/ab/netbsd-5-1-RELEASE/i386/201011061943Z-obj/home/builds/ab/netbsd-5-1-RELEASE
/src/sys/arch/i386/compile/GENERIC  and 5DsP4^F^Yg6@'>7^BM    
2M[^L3^O1;1I^Ob0^KeU;W"h:^UH_8Sv^F9^Q^\1<^ 4=^\`^C?Z^Z>^X4m
Jun 13 10:06:39 netbsd-vm savecore: reboot after panic: panic: trap
Jun 13 10:06:39 netbsd-vm savecore: writing compressed core to 
/var/crash/netbsd.1.core.gz
Jun 13 10:06:42 netbsd-vm savecore: writing compressed kernel to 
/var/crash/netbsd.1.gz
Jun 13 10:06:42 netbsd-vm savecore: (null): Bad address

During reboots, I don't notice any panic on the console. 
What could be triggering savecore to write a crash file? What (files?) does it 
compare?

Regards,
/P