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From: Neeraj Upadhyay <>
	Neeraj Upadhyay <>
Subject: [PATCH] cpu/hotplug: Fix acquire of st->should_run in cpuhp_thread_fun()
Date: Wed,  5 Sep 2018 11:22:07 +0530
Message-ID: <> (raw)

The smp_mb() in cpuhp_thread_fun() appears to be misplaced, and
need to be after the load of st->should_run, to prevent
reordering of the later load/stores w.r.t. the load of

Signed-off-by: Neeraj Upadhyay <>
 kernel/cpu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index aa7fe85..eb4041f 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -607,15 +607,15 @@ static void cpuhp_thread_fun(unsigned int cpu)
 	bool bringup = st->bringup;
 	enum cpuhp_state state;
+	if (WARN_ON_ONCE(!st->should_run))
+		return;
 	 * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures
 	 * that if we see ->should_run we also see the rest of the state.
-	if (WARN_ON_ONCE(!st->should_run))
-		return;
 	if (st->single) {
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Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-05  5:52 Neeraj Upadhyay [this message]
2018-09-05  8:12 ` Peter Zijlstra

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