Re: Issues using KGDB on a Linux machine to debug NetBSD

[Reinoud Zandijk <reinoud%NetBSD.org@localhost>]

hi folks,

sorry i'm so late :)

On Fri, Jun 08, 2012 at 01:35:44PM -0700, Israel Jacquez wrote:
> When I invoke dmesg(8): dmesg | grep -E '^com', I get the following:
> com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
> com0: console
> com0: kgdb

and thats the issue: you are multiplexing the com0 port. For a reliable
testbed you need a second com port for the kgdb, say com1. I've used this
setup quite extensively and it works like a charm, even though 115200 baud is
still slowish for kgdb.

An relatively new alternative is to use NetBSD/usermode (i386 and amd64 only
for now). You can then attach a gdb to the usermode process just like kgdb.
Of couse it doesn't give you debugging for PCI stuff yet etc. but for more
generic kernel work, i'd recommend it.

With regards,
Reinoud