From: Neeraj Upadhyay <neeraju@codeaurora.org>
To: tglx@linutronix.de, josh@joshtriplett.org, peterz@infradead.org,
mingo@kernel.org, jiangshanlai@gmail.com, dzickus@redhat.com,
brendan.jackman@arm.com, malat@debian.org, mojha@codeaurora.org
Cc: linux-kernel@vger.kernel.org, sramana@codeaurora.org,
linux-arm-msm@vger.kernel.org,
Neeraj Upadhyay <neeraju@codeaurora.org>
Subject: [PATCH] cpu/hotplug: Fix acquire of st->should_run in cpuhp_thread_fun()
Date: Wed, 5 Sep 2018 11:22:07 +0530 [thread overview]
Message-ID: <1536126727-11629-1-git-send-email-neeraju@codeaurora.org> (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
st->should_run.
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
---
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.
*/
smp_mb();
- if (WARN_ON_ONCE(!st->should_run))
- return;
-
cpuhp_lock_acquire(bringup);
if (st->single) {
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member of the Code Aurora Forum, hosted by The Linux Foundation
next reply other threads:[~2018-09-05 5:52 UTC|newest]
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 ` [PATCH] cpu/hotplug: Fix acquire of st->should_run in cpuhp_thread_fun() Peter Zijlstra
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