Commit-ID:  99d84bf8c65a7a0dbc9e166ca0a58ed949ac4f37
Gitweb:     https://git.kernel.org/tip/99d84bf8c65a7a0dbc9e166ca0a58ed949ac4f37
Author:     Peter Zijlstra <[email protected]>
AuthorDate: Wed, 29 May 2019 20:36:37 +0000
Committer:  Peter Zijlstra <[email protected]>
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) <[email protected]>
Cc: Aaron Lu <[email protected]>
Cc: Valentin Schneider <[email protected]>
Cc: [email protected]
Cc: Phil Auld <[email protected]>
Cc: Julien Desfossez <[email protected]>
Cc: Nishanth Aravamudan <[email protected]>
Link: 
https://lkml.kernel.org/r/0fd8fd4b99b9b9aa88d8b2dff897f7fd0d88f72c.1559129225.git.vpil...@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();
 

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