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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 F0711C1975A for ; Fri, 13 Mar 2020 02:40:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9ECF2072F for ; Fri, 13 Mar 2020 02:40:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584067209; bh=6V5034ysnLgvvbSebr5dC4ZNWLB0UT9n3wnteW3uwVg=; h=Date:From:To:Cc:Subject:Reply-To:List-ID:From; b=pPr/3EDwUhB69RAwOaLdzFNDXt8hNPTbpUFWly6/7ilo0Ovlus1J6kiNYviRhsxHe rjUdQ/HgGuarxr3Wk9/sBbibm79Xy1wRTyLBU1U6sqPV6QHPrskd5DZ28wuMoupKIa IgewdvnnLjATdgJKv9A7Ve/1RP2ka2ulc+3KtNZM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726483AbgCMCkI (ORCPT ); Thu, 12 Mar 2020 22:40:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:57514 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726246AbgCMCkH (ORCPT ); Thu, 12 Mar 2020 22:40:07 -0400 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5D92720724; Fri, 13 Mar 2020 02:40:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584067207; bh=6V5034ysnLgvvbSebr5dC4ZNWLB0UT9n3wnteW3uwVg=; h=Date:From:To:Cc:Subject:Reply-To:From; b=bFp9D0vhlP+/Nd+KFmxl+82cn0PsqhUEpxB5XwFyHQiV77McJLVnJRe1WVjA178F7 hqJb18K8x5AEblp+Bua24KMYvCqDp6UuV7KduvZ4oOQrZAa/yQj7Nn/Fwn9bzcAJLZ aPsc5XgLPxRq/Eu7sVyrDroDksuBijPXwHu/JHrQ= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 2A3EF35226F6; Thu, 12 Mar 2020 19:40:07 -0700 (PDT) Date: Thu, 12 Mar 2020 19:40:07 -0700 From: "Paul E. McKenney" 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 Subject: [PATCH RFC tip/core/rcu 0/2] Fix RCU idle-exit problem and comment Message-ID: <20200313024007.GA27492@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! This series fixes a brown-paper-bag NMI self-deadlock bug located by Thomas Gleixner and adds comments: 1. Don't acquire lock in NMI handler in rcu_nmi_enter_common(). 2. Add comments marking transitions between RCU watching and not. These pass light rcutorture testing, and seem like v5.8 material. Thanx, Paul ------------------------------------------------------------------------ tree.c | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-)