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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 A137AC4CEC4 for ; Thu, 19 Sep 2019 17:38:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 748A02053B for ; Thu, 19 Sep 2019 17:38:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="eAjD1tCq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403841AbfISRid (ORCPT ); Thu, 19 Sep 2019 13:38:33 -0400 Received: from mail.efficios.com ([167.114.142.138]:33648 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390954AbfISRic (ORCPT ); Thu, 19 Sep 2019 13:38:32 -0400 Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 900A833186E; Thu, 19 Sep 2019 13:38:31 -0400 (EDT) Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10032) with ESMTP id 05m-jx4UA0eJ; Thu, 19 Sep 2019 13:38:30 -0400 (EDT) Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id BFD39331856; Thu, 19 Sep 2019 13:38:30 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com BFD39331856 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1568914710; bh=FAbnlBYHkpKoL/bnDfXB8638h4RpnPFzbHOMT8XjsZY=; h=From:To:Date:Message-Id; b=eAjD1tCqmE7NebiHqgJzNL77E1yztgyk4i6EqWJwRGdl2cmAivPKE96LimVLbzL9C xOSnk7VMXs0b+i6n1w6gpQVpnCsEwLVebjuMwGlRzD9cTlsp204w1wZ6GaM2CAHd+k DLZVVIgGz8x8t9txNvItOOgMErODWaOj1wRHTroCdy1pDaCPdcZuye6N77W3QiXaBm hGK6U5fmV0aQ3ndSlqlOFAAkmN6LEbqUY91OwueUWYjWqN2DvBMtHDwcPfUndu+zgO xQ3x3ZjE8UyZVgRdDHInTMzIN8f9H7qzQ+t8B+VfYqwakPthVp1K+u38Xts5H6pLd5 jHwas1CUYUWGw== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10026) with ESMTP id 85TqccKKJ5Pj; Thu, 19 Sep 2019 13:38:30 -0400 (EDT) Received: from localhost.localdomain (192-222-181-218.qc.cable.ebox.net [192.222.181.218]) by mail.efficios.com (Postfix) with ESMTPSA id 7CAF6331848; Thu, 19 Sep 2019 13:38:30 -0400 (EDT) From: Mathieu Desnoyers To: Peter Zijlstra , "Paul E. McKenney" Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Oleg Nesterov , "Eric W. Biederman" , Linus Torvalds , Russell King - ARM Linux admin , Chris Metcalf , Christoph Lameter , Kirill Tkhai , Mike Galbraith , Thomas Gleixner , Mathieu Desnoyers Subject: [RFC PATCH for 5.4 1/7] Fix: sched/membarrier: Private expedited registration check Date: Thu, 19 Sep 2019 13:36:59 -0400 Message-Id: <20190919173705.2181-2-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190919173705.2181-1-mathieu.desnoyers@efficios.com> References: <20190919173705.2181-1-mathieu.desnoyers@efficios.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Fix a logic flaw in the way membarrier_register_private_expedited() handles ready state checks for private expedited sync core and private expedited registrations. If a private expedited membarrier registration is first performed, and then a private expedited sync_core registration is performed, the ready state check will skip the second registration when it really should not. Signed-off-by: Mathieu Desnoyers Cc: "Paul E. McKenney" Cc: Peter Zijlstra Cc: Oleg Nesterov Cc: "Eric W. Biederman" Cc: Linus Torvalds Cc: Russell King - ARM Linux admin Cc: Chris Metcalf Cc: Christoph Lameter Cc: Kirill Tkhai Cc: Mike Galbraith Cc: Thomas Gleixner Cc: Ingo Molnar --- kernel/sched/membarrier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index aa8d75804108..5110d91b1b0e 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -226,7 +226,7 @@ static int membarrier_register_private_expedited(int flags) * groups, which use the same mm. (CLONE_VM but not * CLONE_THREAD). */ - if (atomic_read(&mm->membarrier_state) & state) + if ((atomic_read(&mm->membarrier_state) & state) == state) return 0; atomic_or(MEMBARRIER_STATE_PRIVATE_EXPEDITED, &mm->membarrier_state); if (flags & MEMBARRIER_FLAG_SYNC_CORE) -- 2.17.1