[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20200218202226.GJ2935@paulmck-ThinkPad-P72>
Date: Tue, 18 Feb 2020 12:22:26 -0800
From: "Paul E. McKenney" <paulmck@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: rcu@...r.kernel.org, linux-kernel@...r.kernel.org,
kernel-team@...com, mingo@...nel.org, jiangshanlai@...il.com,
dipankar@...ibm.com, akpm@...ux-foundation.org,
mathieu.desnoyers@...icios.com, josh@...htriplett.org,
tglx@...utronix.de, rostedt@...dmis.org, dhowells@...hat.com,
edumazet@...gle.com, fweisbec@...il.com, oleg@...hat.com,
joel@...lfernandes.org
Subject: Re: [PATCH tip/core/rcu 1/3] rcu-tasks: *_ONCE() for
rcu_tasks_cbs_head
On Tue, Feb 18, 2020 at 09:11:42PM +0100, Peter Zijlstra wrote:
> On Tue, Feb 18, 2020 at 08:27:19AM -0800, Paul E. McKenney wrote:
> > On Tue, Feb 18, 2020 at 08:56:48AM +0100, Peter Zijlstra wrote:
>
> > > I just took offence at the Changelog wording. It seems to suggest there
> > > actually is a problem, there is not.
> >
> > Quoting the changelog: "Not appropriate for backporting due to failure
> > being unlikely."
>
> That implies there is failure, however unlikely.
>
> In this particular case there is absolutely no failure, except perhaps
> in KCSAN. This patch is a pure annotation such that KCSAN can understand
> the code.
>
> Like said, I don't object to the actual patch, but I do think it is
> important to call out false negatives or to describe the actual problem
> found.
I don't feel at all comfortable declaring that there is absolutely
no possibility of failure.
Thanx, Paul
Powered by blists - more mailing lists