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 420A1C43465 for ; Fri, 18 Sep 2020 13:44:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C28A20878 for ; Fri, 18 Sep 2020 13:44:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726126AbgIRNoM (ORCPT ); Fri, 18 Sep 2020 09:44:12 -0400 Received: from verein.lst.de ([213.95.11.211]:32784 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725955AbgIRNoM (ORCPT ); Fri, 18 Sep 2020 09:44:12 -0400 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) Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org 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?