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=-7.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 B4839C2BA1A for ; Mon, 6 Apr 2020 01:10:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B9DB2072F for ; Mon, 6 Apr 2020 01:10:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586135438; bh=NapCtnOG7WBPhOJXPKNfQp/uL4cU/eeZHbTCOnYnNfM=; h=Date:From:To:Cc:Subject:Reply-To:List-ID:From; b=XdOZWabDLp66N7gtav75mPFUu88YDnlZXiqnO6a5dpgOMuKIqLuJZFRd60mNGuQvn 8KrIB6PnUcKDg0zdH/T7uAW6xj6aAjl67nVHkAcktFAX5D0qTaD2g8g0o6jn/AzORB bI+2DZRvsn5A7uQy2EnwQjw3dmDNa8ieCoi+Jds0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727833AbgDFBKh (ORCPT ); Sun, 5 Apr 2020 21:10:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:34784 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726436AbgDFBKh (ORCPT ); Sun, 5 Apr 2020 21:10:37 -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 D4A9F2068E; Mon, 6 Apr 2020 01:10:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586135436; bh=NapCtnOG7WBPhOJXPKNfQp/uL4cU/eeZHbTCOnYnNfM=; h=Date:From:To:Cc:Subject:Reply-To:From; b=tPh0ZZ5IXSwmC3JWZ7d9qKNKQgjzkp9UT6hLMBIT1cjxLJjXAaxQ61hdIxhLWiuhD nbFK5NfzmcSb5gUZHHYBC3xxjAGP7FLlXphrn8wN2omSOqMczBn8JGI9eicSeruuiN iyWaWzbIOJTOWubYJVKcwxRx25b7+9sDQE0knUJ0= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id A88093522B2E; Sun, 5 Apr 2020 18:10:36 -0700 (PDT) Date: Sun, 5 Apr 2020 18:10:36 -0700 From: "Paul E. McKenney" To: mingo@kernel.org, tglx@linutronix.de Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org, joel@joelfernandes.org Subject: [GIT PULL rcu/urgent] Don't acquire lock in NMI handler (v5.7) Message-ID: <20200406011036.GA1435@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 pull request contains a single commit that avoid acquiring a lock when rcu_nmi_enter_common() is invoked from an NMI handler. This issue can of course result in self-deadlock, and the fix is quite straightforward. I am therefore putting it forward for the current release (v5.7) instead of following my normal process, which would delay it until v5.8. This fix has been subjected to rcutorture, kbuild test robot, and -next testing and is available at: git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git urgent-for-mingo for you to fetch changes up to bf37da98c51825c90432d340e135cced37a7460d: rcu: Don't acquire lock in NMI handler in rcu_nmi_enter_common() (2020-04-05 14:22:15 -0700) ---------------------------------------------------------------- Paul E. McKenney (1): rcu: Don't acquire lock in NMI handler in rcu_nmi_enter_common() kernel/rcu/tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)