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=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID 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 D7A5DECDFB1 for ; Tue, 17 Jul 2018 19:34:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7F07F20693 for ; Tue, 17 Jul 2018 19:34:37 +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="cF/FvmTl"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="h/jCjWE2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7F07F20693 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 S1729934AbeGQUIk (ORCPT ); Tue, 17 Jul 2018 16:08:40 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:51840 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729720AbeGQUIk (ORCPT ); Tue, 17 Jul 2018 16:08:40 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 0AB396063A; Tue, 17 Jul 2018 19:34:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1531856075; bh=wp+DXpmCNUDdSt/saUxden3kTeprGvOgqYqiZmJZI10=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=cF/FvmTlUoqwsgou1UbdHKH2MsXPZjr5KdjiHuoPuDn7MWQ4Ozlhv6Ue+xvQoxwTc UwF8XFOH3tF5qp+Taf2T7IujETA7W4uuDBoawLd4gGFhv5PEEwWUMfr6WJaCTZPNJf rCYW/9uuWrIP2rXEbEvRtlInnxMQsCGaOJaTGIrw= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 56FA46063A; Tue, 17 Jul 2018 19:34:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1531856074; bh=wp+DXpmCNUDdSt/saUxden3kTeprGvOgqYqiZmJZI10=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=h/jCjWE2Bnc2ktG0Txeqa2D3w2sUBtOmt/fYj4/Ccugp4qzXPKvbkB7Mrs481TR+C LtZppkLoJjQhkWzBIVqr9LnNgrsHWsFL9s79BIWqTTlE4E15cvN9b+hfChxUCuUltS Bd5PIEcZMmZgftd6cRRIsiRzxI0prtdP7lMNyeUU= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 17 Jul 2018 12:34:34 -0700 From: isaacm@codeaurora.org To: Peter Zijlstra 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 In-Reply-To: <20180717183450.GL2494@hirez.programming.kicks-ass.net> References: <1531845017-19935-1-git-send-email-isaacm@codeaurora.org> <20180717183450.GL2494@hirez.programming.kicks-ass.net> Message-ID: X-Sender: isaacm@codeaurora.org User-Agent: Roundcube Webmail/1.2.5 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alright, we will make a new patch for this. Thanks for the feedback. Thanks, Isaac Manjarres On 2018-07-17 11:34, Peter Zijlstra wrote: > 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.