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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 B45DEC61DD8 for ; Wed, 28 Oct 2020 01:47:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F94620720 for ; Wed, 28 Oct 2020 01:47:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726128AbgJ1Bif (ORCPT ); Tue, 27 Oct 2020 21:38:35 -0400 Received: from mail-out.m-online.net ([212.18.0.9]:42060 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1832999AbgJ0X0V (ORCPT ); Tue, 27 Oct 2020 19:26:21 -0400 Received: from frontend01.mail.m-online.net (unknown [192.168.8.182]) by mail-out.m-online.net (Postfix) with ESMTP id 4CLSWZ43TGz1qrf4; Wed, 28 Oct 2020 00:26:18 +0100 (CET) Received: from localhost (dynscan1.mnet-online.de [192.168.6.70]) by mail.m-online.net (Postfix) with ESMTP id 4CLSWZ2sGWz1qxh0; Wed, 28 Oct 2020 00:26:18 +0100 (CET) X-Virus-Scanned: amavisd-new at mnet-online.de Received: from mail.mnet-online.de ([192.168.8.182]) by localhost (dynscan1.mail.m-online.net [192.168.6.70]) (amavisd-new, port 10024) with ESMTP id 5rzp0rheSnFs; Wed, 28 Oct 2020 00:26:17 +0100 (CET) X-Auth-Info: RS9aI4PlyTCBHGWJrSWEDVriYnK+Ge5YcPCqkwJrXrVC6IGL/CAq2pX641Nc5O6k Received: from igel.home (ppp-46-244-161-64.dynamic.mnet-online.de [46.244.161.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mnet-online.de (Postfix) with ESMTPSA; Wed, 28 Oct 2020 00:26:17 +0100 (CET) Received: by igel.home (Postfix, from userid 1000) id E56742C2B09; Wed, 28 Oct 2020 00:26:16 +0100 (CET) From: Andreas Schwab To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] powerpc/uaccess: Switch __put_user_size_allowed() to __put_user_asm_goto() References: <94ba5a5138f99522e1562dbcdb38d31aa790dc89.1599216721.git.christophe.leroy__44535.5968013004$1599217383$gmane$org@csgroup.eu> X-Yow: Here we are in America... when do we collect unemployment? Date: Wed, 28 Oct 2020 00:26:16 +0100 In-Reply-To: <94ba5a5138f99522e1562dbcdb38d31aa790dc89.1599216721.git.christophe.leroy__44535.5968013004$1599217383$gmane$org@csgroup.eu> (Christophe Leroy's message of "Fri, 4 Sep 2020 11:01:30 +0000 (UTC)") Message-ID: <87mu079ron.fsf@igel.home> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sep 04 2020, Christophe Leroy wrote: > __put_user_asm_goto() provides more flexibility to GCC and avoids using > a local variable to tell if the write succeeded or not. > GCC can then avoid implementing a cmp in the fast path. That breaks CLONE_CHILD_SETTID. I'm getting an assertion failure in __libc_fork (THREAD_GETMEM (self, tid) != ppid). Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."