5.4-dropping to debugger

[Eirik Øverby]

Hi, every once in a while (about once a week lately), one of my  
servers has been known to stop responding. Upon connecting the serial  
console, I find myself at a debugger prompt. This is the output I've  
gotten this time.

I do think I have a debug kernel on that machine, what can I do to  
get more useful information out?

PS: I have seen various kinds of instability on most of my 5.4- 
installations, no matter the patchlevel. This box is just one of many.

Anyone?

/Eirik

db>
db> c
Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address   = 0x2007010
fault code              = supervisor write, page not present
instruction pointer     = 0x8:0xc0581fe8
stack pointer           = 0x10:0xe3384c40
frame pointer           = 0x10:0xe3384c70
code segment            = base 0x0, limit 0xfffff, type 0x1b
                         = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 29 (irq18: fxp0)
[thread pid 29 tid 100000 ]
Stopped at      fxp_add_rfabuf+0x68:    movw    %ax,0xe(%ebx)
db> trace
Tracing pid 29 tid 100000 td 0xc22a0000
fxp_add_rfabuf(c2404000,c2404500,2,a6c54bb2,b51487f8) at  
fxp_add_rfabuf+0x68
fxp_intr_body(c2404000,c2404000,40,ffffffff,8) at fxp_intr_body+0xf1
fxp_intr(c2404000,0,0,0,0) at fxp_intr+0x14e
ithread_loop(c22f6500,e3384d38,0,0,0) at ithread_loop+0x1b8
fork_exit(c06a9150,c22f6500,e3384d38) at fork_exit+0x80
fork_trampoline() at fork_trampoline+0x8
--- trap 0x1, eip = 0, esp = 0xe3384d6c, ebp = 0 ---