From: "Paul E. McKenney" <paulmck@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Frederic Weisbecker <frederic@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
Neeraj Upadhyay <neeraj.upadhyay@amd.com>,
Uladzislau Rezki <urezki@gmail.com>,
Zqiang <qiang.zhang1211@gmail.com>, rcu <rcu@vger.kernel.org>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Lai Jiangshan <jiangshanlai@gmail.com>
Subject: Re: [PATCH] Revert "rcu-tasks: Fix synchronize_rcu_tasks() VS zap_pid_ns_processes()"
Date: Mon, 29 Apr 2024 11:57:12 -0700 [thread overview]
Message-ID: <c5111e49-613d-492b-aa51-1be4d6101aa0@paulmck-laptop> (raw)
In-Reply-To: <20240429110328.GB1101@redhat.com>
On Mon, Apr 29, 2024 at 01:03:28PM +0200, Oleg Nesterov wrote:
> On 04/25, Frederic Weisbecker wrote:
> >
> > This reverts commit 28319d6dc5e2ffefa452c2377dd0f71621b5bff0. The race
> > it fixed was subject to conditions that don't exist anymore since:
> >
> > 1612160b9127 ("rcu-tasks: Eliminate deadlocks involving do_exit() and RCU tasks")
> >
> > This latter commit removes the use of SRCU that used to cover the
> > RCU-tasks blind spot on exit between the tasklist's removal and the
> > final preemption disabling. The task is now placed instead into a
> > temporary list inside which voluntary sleeps are accounted as RCU-tasks
> > quiescent states. This would disarm the deadlock initially reported
> > against PID namespace exit.
> >
> > Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> > ---
> > include/linux/rcupdate.h | 2 --
> > kernel/pid_namespace.c | 17 -----------------
> > kernel/rcu/tasks.h | 16 +++-------------
> > 3 files changed, 3 insertions(+), 32 deletions(-)
>
> LGTM. FWIW,
>
> Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Queued, thank you both!
Thanx, Paul
prev parent reply other threads:[~2024-04-29 18:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-25 14:24 [PATCH] Revert "rcu-tasks: Fix synchronize_rcu_tasks() VS zap_pid_ns_processes()" Frederic Weisbecker
2024-04-29 11:03 ` Oleg Nesterov
2024-04-29 18:57 ` Paul E. McKenney [this message]
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