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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 28DCAC04AB5 for ; Thu, 6 Jun 2019 04:51:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 06178207E0 for ; Thu, 6 Jun 2019 04:51:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726343AbfFFEvY (ORCPT ); Thu, 6 Jun 2019 00:51:24 -0400 Received: from helcar.hmeau.com ([216.24.177.18]:56208 "EHLO deadmen.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725766AbfFFEvX (ORCPT ); Thu, 6 Jun 2019 00:51:23 -0400 Received: from gondobar.mordor.me.apana.org.au ([192.168.128.4] helo=gondobar) by deadmen.hmeau.com with esmtps (Exim 4.89 #2 (Debian)) id 1hYkMu-0005R1-RB; Thu, 06 Jun 2019 12:51:16 +0800 Received: from herbert by gondobar with local (Exim 4.89) (envelope-from ) id 1hYkMn-0003bD-SH; Thu, 06 Jun 2019 12:51:09 +0800 Date: Thu, 6 Jun 2019 12:51:09 +0800 From: Herbert Xu To: Alan Stern Cc: "Paul E. McKenney" , Boqun Feng , Linus Torvalds , Frederic Weisbecker , Fengguang Wu , LKP , LKML , Netdev , "David S. Miller" , Andrea Parri , Luc Maranget , Jade Alglave Subject: Re: rcu_read_lock lost its compiler barrier Message-ID: <20190606045109.zjfxxbkzq4wb64bj@gondor.apana.org.au> References: <20190603200301.GM28207@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 04, 2019 at 10:44:18AM -0400, Alan Stern wrote: > > Currently the LKMM says the test is allowed and there is a data race, > but this answer clearly is wrong since it would violate the RCU > guarantee. Thank you! This is what I tried to say all along in this thread but you expressed it in a much better way :) -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============4459281011604983741==" MIME-Version: 1.0 From: Herbert Xu To: lkp@lists.01.org Subject: Re: rcu_read_lock lost its compiler barrier Date: Thu, 06 Jun 2019 12:51:09 +0800 Message-ID: <20190606045109.zjfxxbkzq4wb64bj@gondor.apana.org.au> In-Reply-To: List-Id: --===============4459281011604983741== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Tue, Jun 04, 2019 at 10:44:18AM -0400, Alan Stern wrote: > > Currently the LKMM says the test is allowed and there is a data race, = > but this answer clearly is wrong since it would violate the RCU = > guarantee. Thank you! This is what I tried to say all along in this thread but you expressed it in a much better way :) -- = Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt --===============4459281011604983741==--