From owner-freebsd-current  Tue Feb 19  0:10:42 2002
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Date: Tue, 19 Feb 2002 00:10:01 -0800
From: Terry Lambert <tlambert2@mindspring.com>
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To: Julian Elischer <julian@elischer.org>
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.
References: <Pine.BSF.4.21.0202182322050.53728-100000@InterJet.elischer.org>
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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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