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From: Hans Petter Selasky <hselasky@c2i.net>
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Date: Wed, 15 Jul 2009 09:35:44 +0200
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Cc: Robert Huff <roberthuff@rcn.com>
Subject: Re: repeatable panic in ukbd.c
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On Wednesday 15 July 2009 05:16:59 Robert Huff wrote:
> 	After updating to:
>
> FreeBSD 8.0-BETA1 #0: Sun Jul 12 18:26:14 EDT 2009 i386
>
> 	I suddenly have a recurring but irregular panic:
>
> panic: mutex Giant not owned at /usr/src/sys/dev/usb/input/ukbd.c:986
>
> 	and a complete crash dump.
> 	This doesn't seem to be a known problem.  To whom should I
> address this?
>

Hi,

We need the backtrace. When I redid the ukbd driver I added the asserts to 
catch this kind of issues. The solution in many cases is simply to return a 
failure when ukbd is not called having Giant locked. Ukbd has to go away from 
the Giant lock, but I'm not confident about the locking strategy in the 
keyboard system nowadays, so I've deferred the task.

static int
ukbd_enable(keyboard_t *kbd)
{
        mtx_assert(&Giant, MA_OWNED);
        KBD_ACTIVATE(kbd);
        return (0);
}

--HPS