DSI when in dhclient

[Justin Hibbits]

On Thu, 22 May 2014 14:51:04 +0700
Alexey Dokuchaev <danfe at nsu.ru> wrote:

> On Sun, May 11, 2014 at 05:50:07PM -0700, Justin Hibbits wrote:
> > Something odd I've been running into lately on 32-bit powerpc, when
> > I run dhclient on an interface, I get a Data Storage Interrupt
> > dropping me to ddb.  It happens when dhclient is
> > spawning /usr/sbin/arp, and I don't know why.  I can write directly
> > to the page it's trying to write into. [...] Does anyone else see
> > this?
> 
> I sometimes get dropped to ddb(4) due to DSI on Mac mini G4 but
> unrelated to dhclient(8); however, I have a question about kernel
> debugging, so I'd chime in. :)
> 
> While at db> prompt, I can see the backtrace and even "call doadump"
> to save some 37MB of memory.  On subsequent reboot, usual set of
> files under /var/crash is generated, but running kgdb(1) on them for
> postmortem shows nothing except couple of question marks.
> 
> Is crashdump saving/reading is broken on PowerPC these days, or I'm
> just doing it wrongly?
> 
> ./danfe

I fixed that DSI last week at BSDCan, thankfully :)

Regarding kgdb, I've never had luck with using it for postmortem.
Textdumps work, but crashdumps don't, and I don't know why.  The dumps
themselves are generated and look correct, but I think either kgdb
isn't correct, or I may be generating the minidumps incorrectly.

- Justin