From 4fa5cd5245b627db88c9ca08ae442373b02596b4 Mon Sep 17 00:00:00 2001
From: Con Kolivas <kernel@kolivas.org>
Date: Tue, 13 Sep 2016 16:27:05 +1000
Subject: [PATCH] sched/core: Do not use smp_processor_id() with preempt
enabled in smpboot_thread_fn()
We should not be using smp_processor_id() with preempt enabled.
Bug identified and fix provided by Alfred Chen.
Reported-by: Alfred Chen <cchalpha@gmail.com>
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Cc: Alfred Chen <cchalpha@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/2042051.3vvUWIM0vs@hex
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/smpboot.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index 13bc43d1fb227..fc0d8270f69ed 100644
--- a/kernel/smpboot.c
+++ b/kernel/smpboot.c
@@ -122,12 +122,12 @@ static int smpboot_thread_fn(void *data)
if (kthread_should_park()) {
__set_current_state(TASK_RUNNING);
- preempt_enable();
if (ht->park && td->status == HP_THREAD_ACTIVE) {
BUG_ON(td->cpu != smp_processor_id());
ht->park(td->cpu);
td->status = HP_THREAD_PARKED;
}
+ preempt_enable();
kthread_parkme();
/* We might have been woken for stop */
continue;
--
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