From owner-freebsd-current  Tue Feb 19  1:20:13 2002
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Date: Tue, 19 Feb 2002 01:13:55 -0800 (PST)
From: Julian Elischer <julian@elischer.org>
To: Terry Lambert <tlambert2@mindspring.com>
Cc: Matthew Dillon <dillon@apollo.backplane.com>,
	Peter Wemm <peter@wemm.org>, current@FreeBSD.ORG
Subject: Re: Patch sets to date and timing tests with Giant out of userret.
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exactly


On Tue, 19 Feb 2002, Terry Lambert wrote:

> Julian Elischer wrote:
> > The fully safe version of this code is:
> > td->td_retval[0] = td->td_ucred->cr_ruid;
> > td->td_retval[1] = td->td_ucred->cr_uid;
> > return (0);
> > 
> > because td->td_ucred is read-only for it's whole existance.
> 
> ???
> 
> Are you sure that td->td_ucred can't change in the middle,
> to point to a different ucred, as a result of kernel
> preemption?
> 
> -- Terry
> 


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