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Message-ID: <18911.25419.893747.465556@stoffel.org>
Date: Fri, 10 Apr 2009 11:18:35 -0400
From: "John Stoffel" <john@stoffel.org>
To: Pete Zaitcev <zaitcev@redhat.com>
Cc: "John Stoffel" <john@stoffel.org>, Jarek Poplawski <jarkao2@gmail.com>,
       linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
       linux-usb@vger.kernel.org
Subject: Re: usb_mon oops Re: tcpdump crashes 2.6.29.1 (and 2.6.29-rc5)
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Pete> On Thu, 9 Apr 2009 23:01:09 -0400, "John Stoffel" <john@stoffel.org> wrote:
>> Any suggestions of a known good state I should start bisection from?

Pete> No suggestions, sorry. The part of usbmon that peeks at DMA-ed
Pete> data wasn't touched since December 2006. It worked fine since
Pete> then, your oops is the first. So, I don't expect bisection to
Pete> help.  At best you're going to find the commit where uvcvideo
Pete> was merged.

I guess my next step would be to unload that module and see if the
crash happens while I have usbmon loaded.

Pete> The right way forward is to deduce what's going on, IMHO. Maybe
Pete> usbmon is trying to take an address in the GART aperture and
Pete> convert it into a struct page. Or the direction in URB
Pete> mismatches endpoint.  Or any number of other things.

I do have the Radeon driver installed, with DRI, etc.  

Pete> I'm working on it, but I'm not done with puzzling out the dmesg
Pete> you sent me, sorry again.

Let me know if you want me to put in debugging messages or try for
more netconsole output.  I built a bunch of kernels last night, but
ran out of reboot time (learning git...) to test them.  I figured I'd
go back to 2.6.26 and see if I had the problem there.  If not, it's a
good start for bisection.

I'll keep poking at this, though tax time is starting to fill my time
right now too.  :]

John

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