Subject: Re: Process credentials change
To: Christos Zoulas <>
From: Bill Studenmund <>
List: tech-kern
Date: 07/10/2006 16:36:20
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On Mon, Jul 10, 2006 at 10:57:37PM +0000, Christos Zoulas wrote:
> In article <>,
> Jason Thorpe  <> wrote:
> >
> >On Jul 10, 2006, at 1:39 PM, Bill Studenmund wrote:
> >
> >Unless you consider that an LWP entering the kernel is like a =20
> >"transaction", and that the credential state should remain constant =20
> >from the beginning to the end of the "transaction".  Do you agree?
> >
> >If so, then it makes PERFECT sense to set the LWP's creds upon kernel =
> >entry, and not change those creds unless the LWP is requesting a cred =
> >change.  That way, a cred change by the proc while the LWP sleeps =20
> >(disk I/O?) won't screw up whatever the LWP is (legitimately) trying =20
> >to do with the creds it started out with.
> Seeing that credential changes happen rather infrequently, doesn't it
> make more sense to update the credential pointers of each lwp when the
> change is happening rather than upon each kernel entry?

No. The idea Jason's going with is that you look at what the credentials=20
are when you start a system call, and you leave them alone during the=20
call. So you only change an LWP's credentials at a very set time.

Take care,


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