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=-13.1 required=3.0 tests=BAYES_00,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=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 B0F40C433E2 for ; Mon, 31 Aug 2020 18:03:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 82D452083E for ; Mon, 31 Aug 2020 18:03:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598896993; bh=90MadMgN8o3HpOyPeyMVAosKnpX8VPQY4+XK0zBBVd4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nIfy1fDEnJhjgXzCk4BHKllptm1jC5jSvgVW5ZovlRiFxQDlSeQttP8h618mtYSWB rhdfSHptzSiRJsWOMSkUrwg4NOMRFBeCq9o1xX0upsC7XfTO0bSse9yMJBZnzw1pc1 E9UWMopOUBCa8h7a2ArPWEDKjIiNgNL72+AxtqPw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729261AbgHaSDJ (ORCPT ); Mon, 31 Aug 2020 14:03:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:36142 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728776AbgHaSB0 (ORCPT ); Mon, 31 Aug 2020 14:01:26 -0400 Received: from paulmck-ThinkPad-P72.home (unknown [50.45.173.55]) (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 45D4221556; Mon, 31 Aug 2020 18:01:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598896884; bh=90MadMgN8o3HpOyPeyMVAosKnpX8VPQY4+XK0zBBVd4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uZFn5zscUsOX/1eG7bhNjgA/uanhfNLuFkCfWfPnP41VxwLPvWhhV5Pk/wu/DKC2u gwvAFQ5LTarlmx7AT6FkEhxNf5z3VzLfJ2UnGYzOVf/DB+cz2AEb85ZZ9CE6435rFX IjHHpnWh3xsJzwdB8daWi27tEIZz+5C+rlrPEyKo= 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 14/24] rcu: Add READ_ONCE() to rcu_do_batch() access to rcu_cpu_stall_ftrace_dump Date: Mon, 31 Aug 2020 11:01:06 -0700 Message-Id: <20200831180116.32690-14-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20200831180050.GA32590@paulmck-ThinkPad-P72> References: <20200831180050.GA32590@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" Given that sysfs can change the value of rcu_cpu_stall_ftrace_dump at any time, this commit adds a READ_ONCE() to the accesses to that variable. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree_stall.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index a1780a6..0fde39b 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -623,7 +623,7 @@ static void check_cpu_stall(struct rcu_data *rdp) /* We haven't checked in, so go dump stack. */ print_cpu_stall(gps); - if (rcu_cpu_stall_ftrace_dump) + if (READ_ONCE(rcu_cpu_stall_ftrace_dump)) rcu_ftrace_dump(DUMP_ALL); } else if (rcu_gp_in_progress() && @@ -632,7 +632,7 @@ static void check_cpu_stall(struct rcu_data *rdp) /* They had a few time units to dump stack, so complain. */ print_other_cpu_stall(gs2, gps); - if (rcu_cpu_stall_ftrace_dump) + if (READ_ONCE(rcu_cpu_stall_ftrace_dump)) rcu_ftrace_dump(DUMP_ALL); } } -- 2.9.5