ccd(4): Fatal trap 18: integer divide fault while in kernel mode

[Robin Breathe]

Caught a panic in ccd under 5.1-BETA-20030526-JPSNAP (GENERIC with 
unused devices disabled, zero_copy(9) and polling(4)) while rsyncing a 
number of ~50MB files onto a 2-disk ccd stripe
(ccd0 1152 none /dev/ad4s1d /dev/ad7s1d; ...; newfs -U /dev/ccd0d).

Irritatingly, the panic was only repeatable under a kernel with 
INVARIANTS/WITNESS disabled, and no dump device defined, but when I 
recompiled with them enabled, and created a large enough dump partition, 
it disappeared.  I've been unable to repeat the panic since (in either 
state).

Anyway, this is what we have, in case it means anything to anyone:

Fatal trap 18: integer divide fault while in kernel mode
instruction pointer     = 0x8:0xc2e4b9e2
stack pointer           = 0x10:0xdf11cbac
frame pointer           = 0x10:0xdf11cbec
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         = 4 (g_down)
kernel: type 18 trap, code=0
Stopped at      ccdbuffer+0x162:        idivl   0(%esi),%eax
db> trace
ccdbuffer(df11cc28,c63d2800,c6ae1870,0,ffd51458) at ccdbuffer+0x162
ccdstart(c63d2800,c6ae1870,1,0,aa28b000) at ccdstart+0x75
ccdstrategy(c6ae1870,0,c0392637,53,0) at ccdstrategy+0xa6
g_disk_start(c673a990,0,c0392a89,159,64) at g_disk_start+0x19e
g_io_schedule_down(c21ae000,c21ae000,df11cd34,c0200d2e,0) at
g_io_schedule_down+0x19c
g_down_procbody(0,df11cd48,c03943dd,2f8,0) at g_down_procbody+0x28
fork_exit(c01e32f0,0,df11cd48) at fork_exit+0xae
fork_trampoline() at fork_trampoline+0x1a
--- trap 0x1, eip = 0, esp = 0xdf11cd7c, ebp = 0 ---
db>

Is there anything more useful I can provide with what I have?  (debug 
kernel compiled, but no dump to get specifics from... I'm not a gdb expert).

I'll continue to try and replicate the initial panic, and get some more 
helpful data.

- Robin

-- 
_____________________________________________________________________
[  Robin Breathe  |  robin at isometry dot net  |  +44 1865 741800  ]