[RFC][PATCH 01/16] stop_machine: Fix stop_cpus_in_progress ordering

Peter Zijlstra
2019-02-18T17:42:04Z

Make sure the entire for loop has stop_cpus_in_progress set.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/stop_machine.c | 2 ++
1 file changed, 2 insertions(+)

--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -375,6 +375,7 @@ static bool queue_stop_cpus_work(const s
*/
preempt_disable();
stop_cpus_in_progress = true;
+ barrier();
for_each_cpu(cpu, cpumask) {
work = &per_cpu(cpu_stopper.stop_work, cpu);
work->fn = fn;
@@ -383,6 +384,7 @@ static bool queue_stop_cpus_work(const s
if (cpu_stop_queue_work(cpu, work))
queued = true;
}
+ barrier();
stop_cpus_in_progress = false;
preempt_enable();