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From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com,
	dipankar@in.ibm.com, akpm@linux-foundation.org,
	mathieu.desnoyers@efficios.com, josh@joshtriplett.org,
	tglx@linutronix.de, rostedt@goodmis.org, dhowells@redhat.com,
	edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com,
	joel@joelfernandes.org
Subject: Re: [PATCH tip/core/rcu 1/3] rcu-tasks: *_ONCE() for rcu_tasks_cbs_head
Date: Tue, 18 Feb 2020 21:11:42 +0100	[thread overview]
Message-ID: <20200218201142.GF11457@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20200218162719.GE2935@paulmck-ThinkPad-P72>

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.

  reply	other threads:[~2020-02-18 20:12 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-15  0:24 [PATCH tip/core/rcu 0/3] Tasks-RCU updates for v5.7 Paul E. McKenney
2020-02-15  0:25 ` [PATCH tip/core/rcu 1/3] rcu-tasks: *_ONCE() for rcu_tasks_cbs_head paulmck
2020-02-17 12:38   ` Peter Zijlstra
2020-02-17 18:16     ` Paul E. McKenney
2020-02-18  7:56       ` Peter Zijlstra
2020-02-18 16:27         ` Paul E. McKenney
2020-02-18 20:11           ` Peter Zijlstra [this message]
2020-02-18 20:22             ` Paul E. McKenney
2020-02-18 22:45               ` Steven Rostedt
2020-02-18 22:54                 ` Paul E. McKenney
2020-02-18 23:13                   ` Steven Rostedt
2020-02-18 23:54                     ` Paul E. McKenney
2020-02-19  0:01                   ` Joel Fernandes
2020-02-19  0:16                     ` Paul E. McKenney
2020-02-19  1:13                       ` Joel Fernandes
2020-02-19  1:48                         ` Paul E. McKenney
2020-02-17 18:23     ` Joel Fernandes
2020-02-17 18:38       ` Marco Elver
2020-02-17 19:32         ` Joel Fernandes
2020-02-15  0:25 ` [PATCH tip/core/rcu 2/3] rcu: Add missing annotation for exit_tasks_rcu_start() paulmck
2020-02-17 14:44   ` Joel Fernandes
2020-02-17 23:10     ` Paul E. McKenney
2020-02-15  0:25 ` [PATCH tip/core/rcu 3/3] rcu: Add missing annotation for exit_tasks_rcu_finish() paulmck

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