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 77E6BC3A5A2 for ; Tue, 3 Sep 2019 20:11:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D75C21883 for ; Tue, 3 Sep 2019 20:11:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="o6MfYU03" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726865AbfICULy (ORCPT ); Tue, 3 Sep 2019 16:11:54 -0400 Received: from mail.efficios.com ([167.114.142.138]:39260 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725882AbfICULx (ORCPT ); Tue, 3 Sep 2019 16:11:53 -0400 Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 6D8A02B2589; Tue, 3 Sep 2019 16:11:52 -0400 (EDT) Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10032) with ESMTP id KyOEx7lq0jNU; Tue, 3 Sep 2019 16:11:52 -0400 (EDT) Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 0B52D2B2586; Tue, 3 Sep 2019 16:11:52 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 0B52D2B2586 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1567541512; bh=iwtH5ywrwMVvHiKE12beJe96zHEyZoGbFTo33anfH5E=; h=From:To:Date:Message-Id; b=o6MfYU03JfQK68wMf+N2NSC9iCm1j48Be/FUKRvKPy2UdhwZatYPzayJ+u8P3oSF4 /RSQPOzm8T5y6H0uRlyhcfHZC16drwP8urbBm9tHVMvJh1vOyw/Gc+VtlcMSJHxEcF pLisDVa6cJ7YbXWF3Fyt302fKTjql7ufTh9nxJ9wja8ud5hIAizPF8n9srLXGNAQrK hXN65dYWiwMzHm11D4f4ZpS7dPQ5EpuX/RTkbLWs3rxgSSLGaRqJEJy65vhBFTGZLR nKylNiv2Mv/ylsuTLx/sBc89f/upDLWOwl8EJVnafWqJePlWoF5ecQL/GjRzvMLeeK hXupHqhMqOC4Q== 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 BHzxL5FJwvup; Tue, 3 Sep 2019 16:11:51 -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 AFDA62B2581; Tue, 3 Sep 2019 16:11:51 -0400 (EDT) From: Mathieu Desnoyers To: "Paul E. McKenney" , Peter Zijlstra , Linus Torvalds Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Oleg Nesterov , "Eric W. Biederman" , Russell King - ARM Linux admin , Chris Metcalf , Christoph Lameter , Kirill Tkhai , Mike Galbraith , Thomas Gleixner , Ingo Molnar Subject: [RFC PATCH 2/2] Fix: sched/membarrier: private expedited registration check Date: Tue, 3 Sep 2019 16:11:35 -0400 Message-Id: <20190903201135.1494-2-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190903201135.1494-1-mathieu.desnoyers@efficios.com> References: <20190903201135.1494-1-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 d564ca1b5d69..e962d47ea6b4 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -265,7 +265,7 @@ 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) & ready_state)) + if ((atomic_read(&mm->membarrier_state) & ready_state) == ready_state) return 0; if (flags & MEMBARRIER_FLAG_SYNC_CORE) set_state |= MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE; -- 2.17.1