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Date:      Thu, 15 Apr 2004 14:35:25 -0400
From:      John Baldwin <jhb@FreeBSD.org>
To:        Mike Silbersack <silby@silby.com>
Cc:        cvs-all@FreeBSD.org
Subject:   Re: cvs commit: src/sys/dev/random randomdev.c
Message-ID:  <200404151435.25450.jhb@FreeBSD.org>
In-Reply-To: <20040415023200.D10243@odysseus.silby.com>
References:  <200404120913.i3C9DOkd075451@repoman.freebsd.org> <200404132258.31816.jhb@FreeBSD.org> <20040415023200.D10243@odysseus.silby.com>

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On Thursday 15 April 2004 03:32 am, Mike Silbersack wrote:
> On Tue, 13 Apr 2004, John Baldwin wrote:
> > You should drop the lock before uiomove().  If the uio can possibly
> > reference user memory, then uiomove() will do a copyout() which can fault
> > and thus sleep if the page is in swap.
> >
> > --
> > John Baldwin <jhb@FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
>
> I'm going to have a similar problem in sendfile when I try to de-giantify
> it, and I'm sure read / write will have issues as well... will WITNESS
> catch this potential problem?

Not currently.  One could add a WITNESS_WARN() check to uiomove() fairly 
easily though to force witness to catch this.

-- 
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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