Received: by 2002:a25:e7d8:0:0:0:0:0 with SMTP id e207csp1208387ybh; Thu, 12 Mar 2020 19:41:16 -0700 (PDT) X-Google-Smtp-Source: ADFU+vsiPW5MuEkHk+0slDbt460zjDHF9kCT3LFujXb2pbsow4DVCd/x4dJYaHm7hX/QgfogJNHJ X-Received: by 2002:a9d:4f0:: with SMTP id 103mr5655288otm.336.1584067276047; Thu, 12 Mar 2020 19:41:16 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1584067276; cv=none; d=google.com; s=arc-20160816; b=LgyogFy5WxvHIcflhqD8RZZP5xekNnNmgqZ3QNn8+15FJ5rXLXxFouMHjxBSabcAIk ovfMZzMAbMFmWfWAMkId1zACybvOZbAUbvGL220VysfTuPFg9jab01xZtnrq5lEDS0vV gl6YRTsvYtK+YuCJ2dWCCLnCp4C56Iu4i7fi9p5cgvG0+duXOBAY1Cp7U3Etz4xAgYcr zeQIlvKFUUDqlMu5ljAykU909Z+Y3ugmJJqUFHR5WEaQdoDml3dliLM5qyas25uuDCSC lS1f4TyzlclvDIDAyrYPmfSEbUa+VpJ/S4mUwn4n1HEmJJ+AauVFTiyKxhzTJtuDtrLr 2Cng== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:content-disposition :mime-version:reply-to:message-id:subject:cc:to:from:date :dkim-signature; bh=LflSCly955gj6CRKan0yEozqMGu8hzx1ExErsLcr9Hg=; b=A1KSTS99abRXGoGw8AnMzaigWmMAFSyz7sa+X+KZJ+0AsDIZJo2GQ92i+hsWEVBQj/ geRGA5xDYekv+If+XMEBHv/ZlHB9dGN5pstwfNYH2Ty0Ju180vZjcR+yl1TQLsog1xYd VeQ5KGdOEEwfYw8iCeCWxbs1xLOulcVm6TQBiFp7Dz7O2oC9Y8MjV2MUBcOjjaZVg1wO 4oYjblbLilgUjmA+gyjH045CAszMKc+KY9CkLSzblXS6ZDxM2WACupzSUjpOibjQ64sy LbSesZH5jkB+C053q/5xQLgc0eU0lMYcD8BQmGxiMkjOD9pXdwdh85nFDKbdYTc5b92I Fo1A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=bFp9D0vh; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id 127si3561431oig.130.2020.03.12.19.41.03; Thu, 12 Mar 2020 19:41:16 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=bFp9D0vh; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726475AbgCMCkI (ORCPT + 99 others); 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(-)