Re: panic: integer divide fault on 6.1

Joao Barros wrote:
> On 9/9/06, Kris Kennaway <kris_at_obsecurity.org> wrote:
>> On Sat, Sep 09, 2006 at 09:02:35PM +0100, Joao Barros wrote:
>> > On 9/9/06, Max Laier <max_at_love2party.net> wrote:
>> > >
>> > >Can you try to get a dump, trace, or at least figure out which
>> function
>> > >the IP is refering to?
>> > >
>> >
>> > Well, the problem only occurs when I boot from the disk and the
>> > installed kernel doesn't have debug support.
>> > Does 'set dumpdev=' work from the boot loader? I tried some
>> > combinations with no success.
>>
>> No.
>>
>> > I can try and install a 6-STABLE snapshot if there's no way of getting
>> > the info needed.
>>
>> You can either try to install a new kernel with DDB support, or follow
>> the "instruction pointer" method in the developers handbook chapter on
>> kernel debugging.
> 
> I copied a CURRENT kernel from a 200608 snapshot and the problem also
> occurs thus I'm adding current_at_.
> My current laptop doesn't have a serial port so I'm copying this by hand:
> 
> Fatal trap 18: integer divide fault while in kernel mode
> cpuid = 0; apic id = 00
> instruction pointer     = 0x20:0xc08a1fb7
> stack pointer           = 0x28:0xc0c20b14
> frame pointer           = 0x28:0xc0c20b9c
> 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         = 0 (swapper)
> [thread pid 0 tid 0 ]
> Stopped at    __qdivrem+0x3b: divl    %ecx,%eax
> 
> db> bt
> Tracing pid 0 tid0 td 0xc0a0c818
> __qdivrem(37fdfa0,0,0,0,0,...) at __qdivrem+0x3b
> __udivdi3(37fdfa0,0,0,0) at __udivdi3+0x16
> ata_raid_promise_read_meta(c37a5000,c09f4a80,1,8086,c37a5000,...) at
> ata_raid_promise_read_meta+0x9b
> ata_raid_read_metadata(c37a5000,c37a5000,c0c20c70,c06b58a4,c37a5000,...)
> at ata_raid_metadata+0x2be
> ata_raid_subdisk_attach(c37a5000) at ata_raid_subdisk_attach+0x33
> device_attach(c37a5000,c37a5180,c37a5000,c36885c0,0,...) at
> device_attach+0x58
> device_probe_and_attach(c37a5200,c37a5200,c08ec9a9,0,c37a5180,...) at
> bus_generic_attach+0x16
> ad_attach(c37a5200) at ad_attach+0x2c8
> device_attach(c37a5200,c095f2d0,c37a5200,0,c368d800,...) at
> device_attach+0x58
> device_probe_and_attach(c37a5200) at device_probe_and_atach+0xe0
> bus_generic_attach(c3659080,c3659080,ffffffff,0,c37a5200,...) at
> bus_generic_attach+0x16
> ata_identify(c3659080) at ata_identify+0x1c8
> ata_boot_attach(0xc0a11d80,0,c09212e7,47,...) at ata_boot_attach+0x3e
> run_interrupt_drive_config_hooks(0,c1ec00,c1e000,0,c0451065,...) at
> run_interrupt_drive_config_hooks+0x43
> mi_startup() at mi_startup+0x96
> begin() at begin+0x2c
> 
> This board has a Promise SATA raid controller and it is disabled in
> the BIOS. I even tried disabling it through a jumper but it still
> stops.
> 

In sys/dev/ata/ata-raid.h the PROMISE_LBA macro does an unchecked
calculation that apparently can divide by zero.  Soren would likely
understand the root cause of this problem but until then you can patch
the driver to workaround the problem.

	Sam