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Date:      Thu, 17 May 2001 23:55:50 +0100 (BST)
From:      Nick Hibma <n_hibma@qubesoft.com>
To:        Shannon <shannon@widomaker.com>
Cc:        Jon Simola <jon@abccom.bc.ca>, Chris Dillon <cdillon@wolves.k12.mo.us>, <freebsd-hackers@FreeBSD.ORG>
Subject:   Re: FreeBSD 4.3 crashing with USB hub attached...
Message-ID:  <20010517234910.J74536-100000@henny.webweaving.org>
In-Reply-To: <20010516201403.A15517@widomaker.com>

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It starts to look like memory trampling. I changed the code a bit and
all of a sudden the device was accepted and no error 'no report
descriptor' was displayed. :-(

Try and add 'err' to the print statement that prints 'no report
descriptor' in uhid.c. That should give you an indication in what part
of that subroutine the code breaks (if it displays that error at all).

So, I'll start looking for an error like that. *sigh* I HATE those bugs.
They are so hard to find and in the end it is always some stupid little
typo or off-by-one error.

Dfr found an off-by-one error 'implemented' by me the other day
(buffer[sizeof(buffer)] = '\0'). The symptoms were that the code would
crash within throw, which made him chase through the gcc sources and
Fred knows what else. Took him about 3 hours to, by chance, notice the
problem. That cost me a round of beers :-)

Nick

> > I believe I had a similar problem back on 4.2-RELEASE with a PSX->USB adapter.
> > http://www.geocrawler.com/mail/thread.php3?subject=Broken-by-design+USB+device%3F&list=159
> >
> > I sent the offending hardware off to Nick Hibma for him to look at, uh, 4
> > months ago. Is he back from vacation yet?
>
> Did you send him crash details? Would you mind sharing them with me if
> you did? I want to do the same on my system and compare them. Might be
> helpful to compare the two incidents.
>
> I've so far been unable to trigger a kernel panic with any other USB
> hardware.  I have another force feedback device to try and that's
> pretty much it for me.
>
> After that I will submit a more detailed bug report if possible.
>
> --
> shannon@widomaker.com  _________________________________________________
> ______________________/ armchairrocketscientistgraffitiexenstentialist
>  "And in billows of might swell the Saxons before her,-- Unite, oh
>  unite!  Or the billows burst o'er her!" -- Downfall of the Gael
>
> To Unsubscribe: send mail to majordomo@FreeBSD.org
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>

--
Qube Software, Ltd.                                             Private:
n_hibma@qubesoft.com                              n_hibma@webweaving.org
                                                     n_hibma@FreeBSD.ORG
http://www.qubesoft.com/                   http://www.etla.net/~n_hibma/


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