FreeBSD 7.0 kernel panic

[Gavin Atkinson]

On Mon, 2009-01-12 at 21:27 +0300, L1NYX01D at GOOGLEMAIL.COM wrote:
> Hello, FreeBSD-stable.
> 
> Last week I have a lot of kernel panics like:

Firstly: are these new panics on a system that has been reliable until
now, or has something changed on the system recently (hardware change,
different software in use, increased load, etc)?  Is there any way you
can reliably reproduce this?  And is the panic message and backtrace
always the same?

> > Fatal trap 12: page fault while in kernel mode
> > cpuid = 0; apic id = 00
> > fault virtual address   = 0x9
> > fault code              = supervisor read, page not present
> > instruction pointer     = 0x20:0xc079f1af
> > stack pointer           = 0x28:0xe5697c80
> > frame pointer           = 0x28:0xe5697cbc
> > code segment            = base 0x0, limit 0xfffff, type 0x1b
> >                         = DPL 0, pres 1, def32 1, gran 1
> > processor eflags        = resume, IOPL = 0
> > current process         = 14 (swi4: clock)
> > trap number             = 12
> > panic: page fault
> > cpuid = 0
> > Uptime: 51m49s
> > Physical memory: 2032 MB
> > Dumping 177 MB: 162 146 130 114 98 82 66 50 34 18 2
> >
> > #0  doadump () at pcpu.h:195
> > 195             __asm __volatile("movl %%fs:0,%0" : "=r" (td));
> > (kgdb) bt
> > #0  doadump () at pcpu.h:195
> > #1  0xc078d1b7 in boot (howto=260) at
> > /usr/src/sys/kern/kern_shutdown.c:409
> > #2  0xc078d479 in panic (fmt=Variable "fmt" is not available.
> > ) at /usr/src/sys/kern/kern_shutdown.c:563
> > #3  0xc0a0eaac in trap_fatal (frame=0xe5697c40, eva=9) at /usr/src/sys/i386/i386/trap.c:899
> > #4  0xc0a0f42f in trap (frame=0xe5697c40) at /usr/src/sys/i386/i386/trap.c:280
> > #5  0xc09f565b in calltrap () at
> > /usr/src/sys/i386/i386/exception.s:139
> > #6  0xc079f1af in softclock (dummy=0x0) at
> > /usr/src/sys/kern/kern_timeout.c:202
> > #7  0xc076f31b in ithread_loop (arg=0xc5101250) at
> > /usr/src/sys/kern/kern_intr.c:1036
> > #8  0xc076c119 in fork_exit (callout=0xc076f170 <ithread_loop>, arg=0xc5101250, frame=0xe5697d38)
> >     at /usr/src/sys/kern/kern_fork.c:781
> > #9  0xc09f56d0 in fork_trampoline () at
> > /usr/src/sys/i386/i386/exception.s:205
> > (kgdb)
> 
> What I should do?

In kgdb, enter "frame 6" then "list".  The output should show where in
the code this occurred.  You can then print any variables that look
interesting by:

p c
p c->ctime

Gavin