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 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 DA11DC43463 for ; Sun, 20 Sep 2020 18:15:10 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E7229207EA for ; Sun, 20 Sep 2020 18:15:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E7229207EA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4BvbMb5B7fzDqhF for ; Mon, 21 Sep 2020 04:15:07 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=ftp.linux.org.uk (client-ip=2002:c35c:fd02::1; helo=zeniv.linux.org.uk; envelope-from=viro@ftp.linux.org.uk; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4BvbJL2Zq1zDqXv for ; Mon, 21 Sep 2020 04:12:18 +1000 (AEST) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kK3om-002bUn-Fx; Sun, 20 Sep 2020 18:12:08 +0000 Date: Sun, 20 Sep 2020 19:12:08 +0100 From: Al Viro To: Andy Lutomirski Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-ID: <20200920181208.GO3421308@ZenIV.linux.org.uk> References: <20200919224122.GJ3421308@ZenIV.linux.org.uk> <36CF3DE7-7B4B-41FD-9818-FDF8A5B440FB@amacapital.net> <20200919232411.GK3421308@ZenIV.linux.org.uk> <20200920025745.GL3421308@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-aio , "open list:MIPS" , David Howells , Linux-MM , keyrings@vger.kernel.org, sparclinux , Christoph Hellwig , linux-arch , linux-s390 , Linux SCSI List , X86 ML , Arnd Bergmann , linux-block , io-uring@vger.kernel.org, linux-arm-kernel , Jens Axboe , Parisc List , Network Development , LKML , LSM List , Linux FS Devel , Andrew Morton , linuxppc-dev Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sun, Sep 20, 2020 at 09:59:36AM -0700, Andy Lutomirski wrote: > As one example, look at __sys_setsockopt(). It's called for the > native and compat versions, and it contains an in_compat_syscall() > check. (This particularly check looks dubious to me, but that's > another story.) If this were to be done with equivalent semantics > without a separate COMPAT_DEFINE_SYSCALL and without > in_compat_syscall(), there would need to be some indication as to > whether this is compat or native setsockopt. There are other > setsockopt implementations in the net stack with more > legitimate-seeming uses of in_compat_syscall() that would need some > other mechanism if in_compat_syscall() were to go away. > > setsockopt is (I hope!) out of scope for io_uring, but the situation > isn't fundamentally different from read and write. Except that setsockopt() had that crap very widespread; for read() and write() those are very rare exceptions. Andy, please RTFS. Or dig through archives. The situation with setsockopt() is *NOT* a good thing - it's (probably) the least of the evils. The last thing we need is making that the norm.