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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D413BC43463 for ; Fri, 18 Sep 2020 13:44:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4E47D20878 for ; Fri, 18 Sep 2020 13:44:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E47D20878 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7E1E46B0055; Fri, 18 Sep 2020 09:44:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 791416B0003; Fri, 18 Sep 2020 09:44:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6A81F6B005C; Fri, 18 Sep 2020 09:44:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0155.hostedemail.com [216.40.44.155]) by kanga.kvack.org (Postfix) with ESMTP id 558D86B0003 for ; Fri, 18 Sep 2020 09:44:11 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 124BA180AD81F for ; Fri, 18 Sep 2020 13:44:11 +0000 (UTC) X-FDA: 77276301102.19.cows82_130841d2712b Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin19.hostedemail.com (Postfix) with ESMTP id D8CB41AD1B9; Fri, 18 Sep 2020 13:44:10 +0000 (UTC) X-HE-Tag: cows82_130841d2712b X-Filterd-Recvd-Size: 2059 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf03.hostedemail.com (Postfix) with ESMTP; Fri, 18 Sep 2020 13:44:09 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 8EEFA68B05; Fri, 18 Sep 2020 15:44:06 +0200 (CEST) Date: Fri, 18 Sep 2020 15:44:06 +0200 From: Christoph Hellwig To: Al Viro Cc: Christoph Hellwig , Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , linux-arm-kernel@lists.infradead.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-ID: <20200918134406.GA17064@lst.de> References: <20200918124533.3487701-1-hch@lst.de> <20200918124533.3487701-2-hch@lst.de> <20200918134012.GY3421308@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918134012.GY3421308@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.17 (2007-11-01) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote: > > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */ > > - return pt_regs_trap_type(current_pt_regs()) == 0x110; > > + return pt_regs_trap_type(current_pt_regs()) == 0x110 || > > + (current->flags & PF_FORCE_COMPAT); > > Can't say I like that approach ;-/ Reasoning about the behaviour is much > harder when it's controlled like that - witness set_fs() shite... I don't particularly like it either. But do you have a better idea how to deal with io_uring vs compat tasks?