Building a DDB friendly kernel/drivers?

[Alexander Sack]

Hi Folks:

I'm debugging an issue with a third-party driver that causes an NMI
during driver initialization.  It only occurs for one version of the
driver thus far.  I want to isolate what triggers the NMI and
generally get a feel for the initialization of the hardware.

I'm running a 6.x-amd64 kernel.  Can someone explain to me why when I
compile the kernel with default debugging options (makeoptions -g,
options DDB/KDB etc. etc.) the kernel comes and boots BUT if I remove
-O2 and -frename-registers (in an effort to make text even close to
readible), the kernel boots and then double-faults on mounting root?

I guess more importantly, what's the RIGHT way to build a DDB/KDB
friendly kernel?  I thought -O2 and/or -frename-registers could cause
DDB to act up but perhaps I'm wrong.

Thanks!

-aps