From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63FE5C43334 for ; Wed, 5 Sep 2018 05:52:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1A72B2073D for ; Wed, 5 Sep 2018 05:52:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="iLNxntR9"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="mHhQUpuL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1A72B2073D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727234AbeIEKUu (ORCPT ); Wed, 5 Sep 2018 06:20:50 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:52546 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726242AbeIEKUt (ORCPT ); Wed, 5 Sep 2018 06:20:49 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 75D95607DC; Wed, 5 Sep 2018 05:52:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1536126739; bh=Bjj9runRAgUuvtri2C2sPVPUxv/h61rXCc2V7svh0i4=; h=From:To:Cc:Subject:Date:From; b=iLNxntR9soSEPb9Fltwz25/lMGu54ZXz6m2wTR4FVy0pNRXrkRJQg/jhogfVi5Ip0 hpFkmqAIrHvjFcaXbwg/pcnquQoSYF9e1QQ8w2u6ZcfBkII9Gf3fvBxejeHLQ7AYqn RZN0UDLk09iD7GJCdEifM3PJa6qJikfbIjkJjKhw= Received: from neeraju-linux.qualcomm.com (blr-c-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: neeraju@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 7BA276038E; Wed, 5 Sep 2018 05:52:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1536126738; bh=Bjj9runRAgUuvtri2C2sPVPUxv/h61rXCc2V7svh0i4=; h=From:To:Cc:Subject:Date:From; b=mHhQUpuLKusuzkUQKx5ONtcbAfpxCS53jI7MTkb3YOga9OnTWxtP/O6oafnz07h8+ PpVe4QbENLpjtMWB7jJL2gIJfboj44m/cBrDpORhNPKlPnJLFJFaFPwz4G1vc/yRBb Nmc1U1jHVjvnMcdOiKwTv2GzZSLomrbVnd9E943o= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 7BA276038E Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=neeraju@codeaurora.org From: Neeraj Upadhyay 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 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: <1536126727-11629-1-git-send-email-neeraju@codeaurora.org> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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