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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 C2497C3F68F for ; Sat, 15 Feb 2020 00:03:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 91481222C4 for ; Sat, 15 Feb 2020 00:03:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581725034; bh=oE+tuDXUM8zX3a79hYiiMgfhDS4aNiQe0Cl9TFrDGXw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=tCL/4PyPrXmmGox36T5LlSWuEAKymGvV1ETilMzyax6YVcaIANan6PlSNZ7T0cibw FcfIADF4XDiGtw/UedopxV9RUJn61WHHTk2ZIjPuPPNq1piOTcQnWjstO51IcfRc1s misqklI3PKDtO+75uTFLU2Ij0VenojCMyN1huaG0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728365AbgBOADy (ORCPT ); Fri, 14 Feb 2020 19:03:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:39276 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727212AbgBOADx (ORCPT ); Fri, 14 Feb 2020 19:03:53 -0500 Received: from paulmck-ThinkPad-P72.c.hoisthospitality.com (unknown [62.84.152.189]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2C3A92187F; Sat, 15 Feb 2020 00:03:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581725032; bh=oE+tuDXUM8zX3a79hYiiMgfhDS4aNiQe0Cl9TFrDGXw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o0BlRvTeanvtRPrmIMJMGQxdmvd8ygzHn88Rk4E1h6jsAKs/lGVoptPfs20h0x5UW xwdfiFlMbY3IRdizqD68zJuA392m7mq1vkVkrIJameKDHxDy+T/mWK3bYQ0tK76gmi F2cEAcO6i6JHaO12LvWvMVSp4kjxxJAV+7iujEC4= From: paulmck@kernel.org To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 3/4] locktorture: Use private random-number generators Date: Fri, 14 Feb 2020 16:03:36 -0800 Message-Id: <20200215000337.14667-3-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20200215000312.GA14585@paulmck-ThinkPad-P72> References: <20200215000312.GA14585@paulmck-ThinkPad-P72> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Paul E. McKenney" Both lock_torture_writer() and lock_torture_reader() use the "static" keyword on their DEFINE_TORTURE_RANDOM(rand) declarations, which means that a single instance of a random-number generator are shared among all the writers and another is shared among all the readers. Unfortunately, this random-number generator was not designed for concurrent access. This commit therefore removes both "static" keywords so that each reader and each writer gets its own random-number generator. Signed-off-by: Paul E. McKenney --- kernel/locking/locktorture.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index 687c1d8..5baf904 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -618,7 +618,7 @@ static struct lock_torture_ops percpu_rwsem_lock_ops = { static int lock_torture_writer(void *arg) { struct lock_stress_stats *lwsp = arg; - static DEFINE_TORTURE_RANDOM(rand); + DEFINE_TORTURE_RANDOM(rand); VERBOSE_TOROUT_STRING("lock_torture_writer task started"); set_user_nice(current, MAX_NICE); @@ -655,7 +655,7 @@ static int lock_torture_writer(void *arg) static int lock_torture_reader(void *arg) { struct lock_stress_stats *lrsp = arg; - static DEFINE_TORTURE_RANDOM(rand); + DEFINE_TORTURE_RANDOM(rand); VERBOSE_TOROUT_STRING("lock_torture_reader task started"); set_user_nice(current, MAX_NICE); -- 2.9.5