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=-3.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 67AD4C43381 for ; Mon, 18 Feb 2019 17:42:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2999C2085A for ; Mon, 18 Feb 2019 17:42:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="J1vAne1o" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391545AbfBRRmC (ORCPT ); Mon, 18 Feb 2019 12:42:02 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:59070 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733227AbfBRRka (ORCPT ); Mon, 18 Feb 2019 12:40:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=wazmGoNtSiaxrHnKqBVW7N6HOF49XHvqZD984DPPNjk=; b=J1vAne1oLcSFoZbhoggDRV2XUU R6d3rsNZNobuH9mxXdrtYbcaz0zCzNm4H0PBBlfH8K82K2rv9iqIsjnLpsmoZvXW4fxQ6xmnYEylA tUMMYdJQ4C+ZWaG5QGBNsi7O+LWb4ldSbJXeLqxiUp74BXSeyKla2+WsOXopnzWQia82pyHrihOEd HN1wVcW0L3o6x8sdwQ+0zD1PyRgu4NoRuS2vxuSw5KWzMrQs1eTzFiJGccQ+tq+hOB+emUrmu9Bpq zY8ssvbWe0OHpQASMA80uru7Usiyke8mIEHM0dHbbUrxg6jZi8tcvvoSPgeXyuArEMZotPc6CuT32 H8UJ5eAQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gvmu1-0005yi-2k; Mon, 18 Feb 2019 17:40:25 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 1746620298A72; Mon, 18 Feb 2019 18:40:23 +0100 (CET) Message-Id: <20190218173513.946214276@infradead.org> User-Agent: quilt/0.65 Date: Mon, 18 Feb 2019 17:56:21 +0100 From: Peter Zijlstra To: mingo@kernel.org, tglx@linutronix.de, pjt@google.com, tim.c.chen@linux.intel.com, torvalds@linux-foundation.org Cc: linux-kernel@vger.kernel.org, subhra.mazumdar@oracle.com, fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com, "Peter Zijlstra (Intel)" Subject: [RFC][PATCH 01/16] stop_machine: Fix stop_cpus_in_progress ordering References: <20190218165620.383905466@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make sure the entire for loop has stop_cpus_in_progress set. Signed-off-by: Peter Zijlstra (Intel) --- kernel/stop_machine.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -375,6 +375,7 @@ static bool queue_stop_cpus_work(const s */ preempt_disable(); stop_cpus_in_progress = true; + barrier(); for_each_cpu(cpu, cpumask) { work = &per_cpu(cpu_stopper.stop_work, cpu); work->fn = fn; @@ -383,6 +384,7 @@ static bool queue_stop_cpus_work(const s if (cpu_stop_queue_work(cpu, work)) queued = true; } + barrier(); stop_cpus_in_progress = false; preempt_enable();