Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6B30C54E94 for ; Thu, 26 Jan 2023 14:21:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231697AbjAZOVJ (ORCPT ); Thu, 26 Jan 2023 09:21:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231506AbjAZOVH (ORCPT ); Thu, 26 Jan 2023 09:21:07 -0500 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77BF4D1; Thu, 26 Jan 2023 06:21:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=h9WIGkvTDhG3zM/vS6F1wiaN1m8XxoyTkKz6L+IxEJs=; b=N7ju3JLaKzUIEy/musw0GNi3MD os+/+yiWUFGrbfQzr8/U9PrhmqB9KtFvAbiejqDjCt5OuNwqyYVWckIHltD2qyCc/m+n23rP5aIF1 asgAjCkOUbu0UUuHIl9+u2BD+hN3J5uS/UHacOhZyGKQBovb0TFI7/jsPIV0s+dOBtNv45K+i5tH5 +kk2Q1L7sTHZtducPRwe7vBSqUGBwt3yN9w/7IZ/nyVw/SLc2mqCntpFWvnnQva1bCgGBFwfquOyn Ey+b/EYg16PetxtVgZ4sleZdXNVYBajAV6ehaHHS3riay9wBDwhKvMyfV93Q4voK+Hmcst+Plfjzv vTCVUGeg==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1pL36d-002TRZ-2Y; Thu, 26 Jan 2023 14:19:59 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 63744300137; Thu, 26 Jan 2023 15:20:29 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 459DA203C2B1E; Thu, 26 Jan 2023 15:20:29 +0100 (CET) Date: Thu, 26 Jan 2023 15:20:29 +0100 From: Peter Zijlstra To: Hernan Ponce de Leon Cc: Waiman Long , paulmck@kernel.org, Arjan van de Ven , mingo@redhat.com, will@kernel.org, boqun.feng@gmail.com, akpm@osdl.org, tglx@linutronix.de, joel@joelfernandes.org, stern@rowland.harvard.edu, diogo.behrens@huawei.com, jonas.oberhauser@huawei.com, linux-kernel@vger.kernel.org, Hernan Ponce de Leon , stable@vger.kernel.org, Jonas Oberhauser Subject: Re: [PATCH] Fix data race in mark_rt_mutex_waiters Message-ID: References: <562c883b-b2c3-3a27-f045-97e7e3281e0b@linux.intel.com> <20230120155439.GI2948950@paulmck-ThinkPad-P17-Gen-1> <9a1c7959-4b8c-94df-a3e2-e69be72bfd7d@huaweicloud.com> <20230123164014.GN2948950@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 26, 2023 at 01:20:07PM +0100, Peter Zijlstra wrote: > Well, set_bit() implies smp_mb(), atomic_long_or() does not and would > need to retain the barrier. set_bit() does not, must've had a brain-fart or so.