Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 8 Aug 2019 03:54:18 -0700
From:   tip-bot for Peter Zijlstra <tipbot@zytor.com>
Message-ID: <tip-99d84bf8c65a7a0dbc9e166ca0a58ed949ac4f37@git.kernel.org>
Cc:     linux-kernel@vger.kernel.org, aaron.lwe@gmail.com,
        naravamudan@digitalocean.com, valentin.schneider@arm.com,
        peterz@infradead.org, tglx@linutronix.de, hpa@zytor.com,
        jdesfossez@digitalocean.com, pauld@redhat.com, mingo@kernel.org
Reply-To: tglx@linutronix.de, peterz@infradead.org,
          valentin.schneider@arm.com, naravamudan@digitalocean.com,
          mingo@kernel.org, hpa@zytor.com, pauld@redhat.com,
          jdesfossez@digitalocean.com, aaron.lwe@gmail.com,
          linux-kernel@vger.kernel.org
In-Reply-To: <0fd8fd4b99b9b9aa88d8b2dff897f7fd0d88f72c.1559129225.git.vpillai@digitalocean.com>
References: <0fd8fd4b99b9b9aa88d8b2dff897f7fd0d88f72c.1559129225.git.vpillai@digitalocean.com>
To:     linux-tip-commits@vger.kernel.org
Subject: [tip:sched/core] stop_machine: Fix stop_cpus_in_progress ordering
Git-Commit-ID: 99d84bf8c65a7a0dbc9e166ca0a58ed949ac4f37
Robot-ID: <tip-bot.git.kernel.org>
Robot-Unsubscribe: Contact <mailto:hpa@kernel.org> to get blacklisted from
 these emails
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset=UTF-8
Content-Disposition: inline
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Commit-ID:  99d84bf8c65a7a0dbc9e166ca0a58ed949ac4f37
Gitweb:     https://git.kernel.org/tip/99d84bf8c65a7a0dbc9e166ca0a58ed949ac4f37
Author:     Peter Zijlstra <peterz@infradead.org>
AuthorDate: Wed, 29 May 2019 20:36:37 +0000
Committer:  Peter Zijlstra <peterz@infradead.org>
CommitDate: Thu, 8 Aug 2019 09:09:30 +0200

stop_machine: Fix stop_cpus_in_progress ordering

Make sure the entire for loop has stop_cpus_in_progress set.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Aaron Lu <aaron.lwe@gmail.com>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: mingo@kernel.org
Cc: Phil Auld <pauld@redhat.com>
Cc: Julien Desfossez <jdesfossez@digitalocean.com>
Cc: Nishanth Aravamudan <naravamudan@digitalocean.com>
Link: https://lkml.kernel.org/r/0fd8fd4b99b9b9aa88d8b2dff897f7fd0d88f72c.1559129225.git.vpillai@digitalocean.com
---
 kernel/stop_machine.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index b4f83f7bdf86..c7031a22aa7b 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -383,6 +383,7 @@ static bool queue_stop_cpus_work(const struct cpumask *cpumask,
 	 */
 	preempt_disable();
 	stop_cpus_in_progress = true;
+	barrier();
 	for_each_cpu(cpu, cpumask) {
 		work = &per_cpu(cpu_stopper.stop_work, cpu);
 		work->fn = fn;
@@ -391,6 +392,7 @@ static bool queue_stop_cpus_work(const struct cpumask *cpumask,
 		if (cpu_stop_queue_work(cpu, work))
 			queued = true;
 	}
+	barrier();
 	stop_cpus_in_progress = false;
 	preempt_enable();