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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT 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 71BB7ECDFB1 for ; Tue, 17 Jul 2018 18:35:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2640B206B8 for ; Tue, 17 Jul 2018 18:35:05 +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="av/L6HRW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2640B206B8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.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 S1730749AbeGQTI4 (ORCPT ); Tue, 17 Jul 2018 15:08:56 -0400 Received: from merlin.infradead.org ([205.233.59.134]:49416 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729717AbeGQTIz (ORCPT ); Tue, 17 Jul 2018 15:08:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=5xqV5Q+eA1wqQnyJNtE/ynk+9r9rqUWGPe61Xnmw9iw=; b=av/L6HRWy8X9enCwLEKxJwt3M 7xG/+tdEZLUq1ISu2QtwF5cplpyDPV1OqzAlZXjWNKU7lYx1MqrWCjqcbolRIsLwLkcYittcDQVc2 v9NKEuoib6sKPOnJsCPoyBewvBv2FLsH8RQo8oJvS1Xg8oiUDA2tU+PlqKF2g3L76YNBFP+BdhrvJ j++pZp4rSyT4vrJJf+PrVJPBB/kyWMEV+zYz6j1xIXkC3Ln7msXrfVSxHuWn7Fq3Cbgh6O0QwX8We MFML38qXxftN/LqTMO8PoZTF8+n4hQFwtZdwSnhOQfIMUyPC4OMSfRGC49EL9ha1FcOC3pXjL642t pfaZICplw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1ffUoH-0002pe-0T; Tue, 17 Jul 2018 18:34:53 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 737E320275F37; Tue, 17 Jul 2018 20:34:50 +0200 (CEST) Date: Tue, 17 Jul 2018 20:34:50 +0200 From: Peter Zijlstra To: "Isaac J. Manjarres" Cc: matt@codeblueprint.co.uk, mingo@kernel.org, tglx@linutronix.de, bigeasy@linutronix.de, linux-kernel@vger.kernel.org, psodagud@codeaurora.org, gregkh@linuxfoundation.org, pkondeti@codeaurora.org, stable@vger.kernel.org Subject: Re: [PATCH v4] stop_machine: Disable preemption after queueing stopper threads Message-ID: <20180717183450.GL2494@hirez.programming.kicks-ass.net> References: <1531845017-19935-1-git-send-email-isaacm@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1531845017-19935-1-git-send-email-isaacm@codeaurora.org> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 17, 2018 at 09:30:17AM -0700, Isaac J. Manjarres wrote: > After cpu_stop_queue_two_works() queues the cpu_stop works > for the stopper threads, it releases the locks held for > both threads, which enables preemption, which allows the > following race condition to occur: Does not apply because an earlier version is already applied. https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/kernel/stop_machine.c?id=9fb8d5dc4b649dd190e1af4ead670753e71bf907 if there still is a problem, please send a new patch that describes the remaining problem.