Re: Sudden reboot

[David Holland <dholland-tech%netbsd.org@localhost>]

On Tue, Dec 03, 2013 at 08:13:29AM +0100, Jan Danielsson wrote:
 >    I'm running netbsd-6 (a month old or so) on a Soekris net6501
 > (NetBSD/amd64), and tonight I had an unexpected reboot.
 > /var/log/messages contains:
 > 
 > Dec  3 03:15:46 aria syslogd[188]: restart
 > Dec  3 03:15:46 aria /netbsd: uvm_fault(0xffffffff8071b4d8, 0x0, 1) -> e
 > Dec  3 03:15:46 aria /netbsd: fatal page fault in supervisor mode
 > Dec  3 03:15:46 aria /netbsd: trap type 6 code 0 rip ffffffff8031162f cs
 > 8 rflags 10283 cr2  60 cpl 4 rsp fffffe8004cf9b98
 > Dec  3 03:15:46 aria /netbsd: panic: trap
 > Dec  3 03:15:46 aria /netbsd: cpu1: Begin traceback...
 > 
 >    Thinking back, I recall noticing that I have had unexpected reboots
 > once or twice before, but it's very rare -- been running this system for
 > a year or so.
 > 
 >    The entry before syslogd restarting is simply a dhcp client renewal
 > (againt my ISP), which occured 03:14:04.
 > 
 >    Trap 6 = illegal op-code? Should I start worrying about broken RAM
 > modules?

from sys/arch/x86/include/trap.h:
#define T_PAGEFLT        6      /* page fault */

and %cr2 contains 60, so in all probability it's just a null pointer
dereference.

If you use objdump -d or nm -n or gdb or whatever to find the code
that's at 0xffffffff8031162f in your kernel, you'll probably get a
fairly good idea of what broke.

-- 
David A. Holland
dholland%netbsd.org@localhost