What do you use for kernel debugging?

[Steven Hartland]

----- Original Message ----- 
From: "Benjamin Kaduk" <kaduk at MIT.EDU>
To: "José Pérez Arauzo" <fbl at aoek.com>
Cc: "FreeBSD Current" <freebsd-current at freebsd.org>
Sent: Sunday, September 28, 2014 8:54 PM
Subject: Re: What do you use for kernel debugging?


> On Sun, 28 Sep 2014, José Pérez Arauzo wrote:
>
>> Hello,
>> I am trying to track down a (deadlock?) issue in CURRENT via DDB. The kernel does
>> not complete hw probes on my Acer V5.
>>
>> I get stuck on apic_isr looping which leads nowhere.
>>
>> So I thought maybe things improve if I debug from another machine.
>>
>>
>> What do you use for kernel debugging? According to the handbook kgdb over serial
>> is a good option, do you agree? I'm on a netbook with no ethernet and no option
>> for firewire: can I have a USB / nullmodem setup to work?
>
> You cannot.
>
>> I have no old-style uarts hardware anymore, as the handbook suggests...
>>
>> Any idea is welcome before I buy extra hw. I have a USB to serial showing up as
>> /dev/cuaU0, do I need to grab another one and a nullmodem cable or there are better
>> alternatives? Thank you.
>
> I'm not sure that there are alternatives at all, unfortunately.
>
> You may be reduced to debugging-via-printf.

dtrace can also be quite invaluable.

    Regards
    Steve