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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 3631CC433E1 for ; Wed, 19 Aug 2020 07:34:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 091BE206B5 for ; Wed, 19 Aug 2020 07:34:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=vt-edu.20150623.gappssmtp.com header.i=@vt-edu.20150623.gappssmtp.com header.b="Nj3F3BC3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726899AbgHSHeP (ORCPT ); Wed, 19 Aug 2020 03:34:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726570AbgHSHeK (ORCPT ); Wed, 19 Aug 2020 03:34:10 -0400 Received: from mail-qk1-x744.google.com (mail-qk1-x744.google.com [IPv6:2607:f8b0:4864:20::744]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0C33C061389 for ; Wed, 19 Aug 2020 00:34:07 -0700 (PDT) Received: by mail-qk1-x744.google.com with SMTP id 2so20748141qkf.10 for ; Wed, 19 Aug 2020 00:34:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=vt-edu.20150623.gappssmtp.com; s=20150623; h=sender:from:to:cc:subject:in-reply-to:references:mime-version :content-transfer-encoding:date:message-id; bh=4V25VWVtltBCvoDctm/BLfmJBIJ+HmrsOxjPE64+VqQ=; b=Nj3F3BC3xyKczep856g1h9CyMlJDYCs1YJNuTqR93+L98c+Pa9l7wcyG/eLo0gHbwy GnGY9yFORoqKHgnC/mu8CxZj9Rs4s8QgsK0TIsEXCPbHpgmef+SxfDlUiZ8c77PqEl7G 1E5AfbjXwonMZHl4bSlJbHgpP6FzS8o1Cx5vOGs3zTY3WiLJQAEmgBdyaY2Zs31E7J/d xYQNGG54DlMxpDDvQ9LN4nj4yHXreqYhYFEGXPidHmixmJs9TWE7yMUYp0o9m5rKsadp jWfFtbcJmuiRlhclWFcTOfSHWxhWKQe9Nz3OryDsvTHHEQmvNs0tvJ22TOkM68+k1OW4 GvvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:in-reply-to:references :mime-version:content-transfer-encoding:date:message-id; bh=4V25VWVtltBCvoDctm/BLfmJBIJ+HmrsOxjPE64+VqQ=; b=mGEVxeLx7fuX1BwYW1vopzsBdcuwxg5Jyfh7j+FhIX8S47esiVDYD4W7QerEayJXdm eBOjTtE7YPoDoUBmfeIy4WHqusWxOJbif3TPIMRKwt6K9BOIUuYlbf6B3YyRXwMcwLSN Y3O927rKnf7RzeMWF7c6Xt8D+qpmaZf7P2bqWOssOSVIi/OUFnSSrWItTto/TyvJ3UxU Janrl0R6n+DALjvYQcvfUVPkUy0SBKjWeixA3qgvrjWPL7XNQRLI8hJfmevCynlOBnNS k9n/4SYbuzCJHi4DzNE1sECqbRdVnP711RibwpdaIY5Ugg+VVvpWTeZLu5Ao8EDGXoj4 gkvQ== X-Gm-Message-State: AOAM530NgU08ttMtQHzl0GPyyDDEkfg4P/GBkhWxcVQjnxSe21haAAzm ksXLu8EzoAP3udQCtPzfMWr7mA== X-Google-Smtp-Source: ABdhPJzxxwMT0A58bbawoYx+tooriUG/ayuWsBOo+fDqxMvTWjyv5RQiVULyZeNBeYSVgyFfcy0M6A== X-Received: by 2002:a37:47cc:: with SMTP id u195mr20561392qka.39.1597822446957; Wed, 19 Aug 2020 00:34:06 -0700 (PDT) Received: from turing-police ([2601:5c0:c000:a8c1::359]) by smtp.gmail.com with ESMTPSA id 20sm26987224qtp.53.2020.08.19.00.34.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Aug 2020 00:34:05 -0700 (PDT) From: "Valdis Kl=?utf-8?Q?=c4=93?=tnieks" X-Google-Original-From: "Valdis Kl=?utf-8?Q?=c4=93?=tnieks" X-Mailer: exmh version 2.9.0 11/07/2018 with nmh-1.7+dev To: Sebastian Andrzej Siewior Cc: Guenter Roeck , Mark Starovoytov , Igor Russkikh , "David S. Miller" , Greg KH , "Ahmed S. Darwish" , linux-kernel@vger.kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, tglx@linutronix.de, will@kernel.org Subject: Re: [PATCH] Revert "seqlock: lockdep assert non-preemptibility on seqcount_t write" In-Reply-To: <20200819070022.semyxepadnvtmtcr@linutronix.de> References: <20200810085954.GA1591892@kroah.com> <20200810095428.2602276-1-a.darwish@linutronix.de> <20200810100502.GA2406768@kroah.com> <169454.1597791078@turing-police> <20200819070022.semyxepadnvtmtcr@linutronix.de> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1597822443_10889P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Wed, 19 Aug 2020 03:34:03 -0400 Message-ID: <15863.1597822443@turing-police> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --==_Exmh_1597822443_10889P Content-Type: text/plain; charset=us-ascii On Wed, 19 Aug 2020 09:00:22 +0200, Sebastian Andrzej Siewior said: > On 2020-08-18 17:56:49 [-0700], Guenter Roeck wrote: > > Nice catch. FWIW, there is no obvious reason why this would need to be atomic. > > The calling code does not set a lock, meaning there can be two (or more) > > callers entering this code. Weird, especially since the code looks like it > > would actually need a mutex to work correctly. It might be interesting to > > see what happens if there are, say, half a dozen scripts/processes trying > > to read the hwmon attribute introduced by this patch at the same time. > > => https://lkml.kernel.org/r/20200818161439.3dkf6jzp3vuwmvvh@linutronix.de Looks reasonable to me, though I've not verified that it's preemptible at that point... --==_Exmh_1597822443_10889P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Comment: Exmh version 2.9.0 11/07/2018 iQIVAwUBXzzV6gdmEQWDXROgAQLTbhAAsvypcbMHOpJZyQfamYXGuY2lN7OfIdhc S5HWEeQpsT/KLRmXDTl65fpNYUcUkrtp7n56JYmIG7O5PHPx9fna2x2X/adqvE02 FrNmboXuo4s0ajokOsA7N8Fgeebjz6+sfr4QNVnatPx71vaPUvZXVXuI1HLhw51M yq6r0eMBNl3JwqXLDcKVcsoAHqjK3WgbUNZnH+aOYUsgnoUb9YfgLLOFXWASd3bd F9griIUcY+Vp5M0z0TUmHR75BDriocvB/0ztg/ePKpuiaZVP7IOYskXYz+KZi6q4 D+KojbYx9xIOWVFW7Op6q2j7Qq6P+9VRpjU7L9qwhKHyQ1fFcEgvrzcI4Wa3LUhN JvcPIo1N1W5FRWl19YBn6w9cLLcSoh4dmoKOeyNFgUP4moR6JqeSoH5hT32vY7js 5IC1DxQ3PLsHSaqbPoTvBoabLvS8q/wcldxt21sZMSQF3Yj68CSQBqCM0ZJxiZEO Dy1POgrNg0rDUfJoEg5utx7Raai8VsUeZbfVc4ZxGdKRKc9mHmShNKzv0zLEcbmo u2e260jtzLr+cV+UaNek4IA2yUw9WvtopsXyYI3tt3octGGgEPjifYALxtJRwg6t DBx6N5tKLO6ROt2so5zSkssWzl9jjHuZ8NbID/dIp85gv7r8dK+49tB+NHU5sOcb CN2QI2uwknQ= =pX+Q -----END PGP SIGNATURE----- --==_Exmh_1597822443_10889P--