trap 12

[vwe at freebsd.org]

On 12/23/-58 20:59, Ian J Hart wrote:
> Is this likely to be hardware? Details will
> follow if not.
> 
> [copied from a screen dump]
> 
> Fatal trap 12: page fault while in kernel mode
> cpuid = 1; apic id = 01
> fault virtual address = 0x0
> fault code = supervisor write data, page not present
> instruction pointer = 0x8:0xffffffff807c6c12
> stack pointer = 0x10:0xffffffff510e7890
> frame pointer = 0x10:0xffffff00054a6c90
> code segment = base 0x0, limit 0xfffff, type 0x1b
> = DPL 0, pres 1, long 1 def32 0, gran 1
> processor eflags = interrupt enabled, resume, IOPL = 0
> current process = 75372 (printf)
> trap number = 12
> panic: page fault
> cpuid = 1
> uptime: 8m2s
> Cannot dump. No dump device defined.
> 
> 

Ian,

it doesn't look like it's hardware. The message basically means, some
code in the kernel was trying to use a NULL pointer (which is by
definition a bad pointer) and tried to do something with it. Do you
experience that message often? Can you reproduce it easily?

To tell you more, we need a backtrace and I'm wondering if you can
manage to get the kernel dump being written and have us getting the
stack backtrace and more debugging information.

If, by any chance, you're using a recent 7.x system, you may want to
enable textdump(4) (AFAIR introduced before 7.1, also look at ddb(8)).
For setting up your system for kernel crashdumps, please have a look at
the handbook and savecore(8). For getting infos out of a kernel
crashdump, please check the developers handbook.

Please try to get us some debug information and we can then most likely
suggest something.

HTH

Volker