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Date:      Sun, 25 May 2003 23:34:36 -0000
From:      Jeff Roberson <jroberson@chesapeake.net>
To:        "Alan L. Cox" <alc@imimic.com>
Cc:        cvs-all@FreeBSD.org
Subject:   Re: cvs commit: src/sys/kern kern_umtx.c
Message-ID:  <20030525193333.Q69975-100000@mail.chesapeake.net>
In-Reply-To: <3ED13356.652D9C44@imimic.com>

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On Sun, 25 May 2003, Alan L. Cox wrote:

> Jeff Roberson wrote:
> >
> > jeff        2003/05/25 11:18:32 PDT
> >
> >   FreeBSD src repository
> >
> >   Modified files:
> >     sys/kern             kern_umtx.c
> >   Log:
> >    - Create a new lock, umtx_lock, for use instead of the proc lock for
> >      protecting the umtx queues.  We can't use the proc lock because we need
> >      to hold the lock across calls to casuptr, which can fault.
> >
> >   Approved by:    re
> >
> >   Revision  Changes    Path
> >   1.3       +13 -6     src/sys/kern/kern_umtx.c
>
> In general, we can sleep on a fault.  Thus, you could be holding this
> mutex at the time of a sleep.
>

That was just pointed out to me.  This patch at least makes things
slightly more correct.

I'm going to have to look at the problem a little closer to see if I can
implement this code without holding a lock across the casuptr.  otherwise
I'll have to use sx.

Cheers,
Jeff



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