From: Oleg Nesterov <oleg@redhat.com>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
"Paul E. McKenney" <paulmck@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 13:03:28 +0200 [thread overview]
Message-ID: <20240429110328.GB1101@redhat.com> (raw)
In-Reply-To: <20240425142404.19927-1-frederic@kernel.org>
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>
next prev parent reply other threads:[~2024-04-29 11:05 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 [this message]
2024-04-29 18:57 ` Paul E. McKenney
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