From: Greg Kroah-Hartman <gre...@linuxfoundation.org>
From: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
commit ce29ddc47b91f97e7f69a0fb7cbb5845f52a9825 upstream.
The function sync_runqueues_membarrier_state() should copy the
membarrier state from the @mm received as parameter to each runqueue
currently running tasks using that mm.
However, the use of smp_call_function_many() skips the current runqueue,
which is unintended. Replace by a call to on_each_cpu_mask().
Fixes: 227a4aadc75b ("sched/membarrier: Fix p->mm->membarrier_state racy load")
Reported-by: Nadav Amit <nadav.a...@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Cc: sta...@vger.kernel.org # 5.4.x+
Link: https://lore.kernel.org/r/74f1e842-4a84-47bf-b6c2-5407dfdd4...@gmail.com
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
kernel/sched/membarrier.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/kernel/sched/membarrier.c
+++ b/kernel/sched/membarrier.c
@@ -471,9 +471,7 @@ static int sync_runqueues_membarrier_sta
}
rcu_read_unlock();
- preempt_disable();
- smp_call_function_many(tmpmask, ipi_sync_rq_state, mm, 1);
- preempt_enable();
+ on_each_cpu_mask(tmpmask, ipi_sync_rq_state, mm, true);
free_cpumask_var(tmpmask);
cpus_read_unlock();
