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Date:      Tue, 19 Oct 2004 16:50:28 -0400
From:      John Baldwin <jhb@freebsd.org>
To:        freebsd-current@freebsd.org
Cc:        Kris Kennaway <kris@obsecurity.org>
Subject:   Re: WITNESS bug
Message-ID:  <200410191650.28544.jhb@FreeBSD.org>
In-Reply-To: <20041019160122.GC55255@xor.obsecurity.org>
References:  <20041019023713.GA1072@green.homeunix.org> <16757.4854.809996.993051@jerusalem.litteratus.org> <20041019160122.GC55255@xor.obsecurity.org>

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On Tuesday 19 October 2004 12:01 pm, Kris Kennaway wrote:
> On Tue, Oct 19, 2004 at 09:13:26AM -0400, Robert Huff wrote:
> > Brian Fundakowski Feldman writes:
> > >  You should never not run with WITNESS_SKIPSPIN if you use
> > >  modules.  Any spin mutexes not listed statically in the witness
> > >  code will cause your machine to immediately panic.
> >
> > 	If this is true (and I'm not disputing it), shouldn't it be
> > noted in GENERIC and/or NOTES?  For that matter, what's the penalty
> > for not automatically including it as part of WITNESS?
>
> Sometimes you don't want to use it, e.g. if you actually want to trace
> spinlock operations with witness.

True spin mutexes should be rarely used anyways, so I don't think modules 
needing spin mutexes is all that big of an issue.  Almost all mutexes should 
just be regular mutexes.

-- 

John Baldwin <jhb@FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/



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