Date: Tue, 30 Sep 2014 22:47:34 +0800 From: Julian Elischer <julian@freebsd.org> To: =?UTF-8?B?Sm9zw6kgUMOpcmV6IEFyYXV6bw==?= <fbl@aoek.com>, Garrett Cooper <yaneurabeya@gmail.com> Cc: FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: What do you use for kernel debugging? Message-ID: <542AC286.8000903@freebsd.org> In-Reply-To: <20140929002025.M8991@aoek.com> References: <20140928071641.M7664@beckpeccoz.com> <761DF16E-5383-46BA-B886-CD3358D976AA@gmail.com> <20140929002025.M8991@aoek.com>
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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 <fbl@aoek.com> 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/<your-architecture>/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" > >
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