From owner-freebsd-current@FreeBSD.ORG Tue Sep 30 14:47:47 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id E4DC8174 for ; Tue, 30 Sep 2014 14:47:47 +0000 (UTC) Received: from vps1.elischer.org (vps1.elischer.org [204.109.63.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "vps1.elischer.org", Issuer "CA Cert Signing Authority" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 8BBCE6D2 for ; Tue, 30 Sep 2014 14:47:47 +0000 (UTC) Received: from Julian-MBP3.local (50-196-156-133-static.hfc.comcastbusiness.net [50.196.156.133]) (authenticated bits=0) by vps1.elischer.org (8.14.9/8.14.9) with ESMTP id s8UEleqf067895 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Tue, 30 Sep 2014 07:47:43 -0700 (PDT) (envelope-from julian@freebsd.org) Message-ID: <542AC286.8000903@freebsd.org> Date: Tue, 30 Sep 2014 22:47:34 +0800 From: Julian Elischer User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: =?UTF-8?B?Sm9zw6kgUMOpcmV6IEFyYXV6bw==?= , Garrett Cooper Subject: Re: What do you use for kernel debugging? References: <20140928071641.M7664@beckpeccoz.com> <761DF16E-5383-46BA-B886-CD3358D976AA@gmail.com> <20140929002025.M8991@aoek.com> In-Reply-To: <20140929002025.M8991@aoek.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Cc: FreeBSD Current X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Sep 2014 14:47:48 -0000 On 9/29/14, 8:31 AM, José Pérez Arauzo wrote: > Hi Garrett, > > On Sun, 28 Sep 2014 13:38:24 -0700, Garrett Cooper wrote >> On Sep 28, 2014, at 0:34, 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? >>> >>> 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. >> There was some discussion recently about this on an internal list. >> Unfortunately no, there isn’t a usable way, but there were some >> interesting viable methods that came up (which haven’t been >> implemented): ethernet/sound/xHCI. >> >> Your best bet, as others have noted, is to use boot -d, use WITNESS >> to spot locking issues, dtrace to isolate which section of code >> there are problems, and finally use one of the DEBUG options noted >> in /sys/conf/NOTES and /sys//conf/NOTES . >> >> Hope that helps! > Well, it's not so encouraging but I'll work on it. > > Do you mean that we can get rid of chapter 10.5 of the handbook (On-Line > Kernel Debugging Using Remote GDB)? no it works when you have the hardware. but modern laptops have so little hardware.. we really will have to define an API/ABI to add to teh current ethernet driver API so that we can do network based debugging. it's getting harder and harder to find alternatives. (though debugging a VM works well). > Just to have it clear, when people develop or fix drivers in FreeBSD > their only option is to use the above mentioned tools, as they have no > access to a live, on-line kernel debugger?? It's disappointing, to say > the least! > > I hope Dcons + 1394 works where it's applicable. > > BR, > > -- > José Pérez Arauzo > > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" > >