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Date: Thu, 24 Apr 2003 21:09:55 -0700
From: David Schultz <das@FreeBSD.ORG>
To: Tim Robbins <tjr@FreeBSD.ORG>
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References: <20030425131656.A93380@dilbert.robbins.dropbear.id.au>
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cc: freebsd-threads@FreeBSD.ORG
Subject: Re: Threading and credential changes
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On Fri, Apr 25, 2003, Tim Robbins wrote:
> I'm trying to understand the way a thread's td_ucred is updated. In ast(),
> cred_update_thread() is called to update it when it doesn't match the one
> stored in the proc. However, setuid() etc. don't set the TDF_ASTPENDING flag
> on any threads, not even the current thread. Am I misunderstanding what ast()
> does, does the thread's cred get updated in some other way, or is this a bug?

This may not answer your question entirely, but rwatson gave a
very nice explanation of how and why ucreds are cached in a post
to current@ a while ago:

http://www.freebsd.org/cgi/getmsg.cgi?fetch=637312+0+/usr/local/www/db/text/2003/freebsd-current/20030209.freebsd-current