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,DKIM_SIGNED, DKIM_VALID,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 0488FC43465 for ; Sat, 19 Sep 2020 22:24:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BCA5121741 for ; Sat, 19 Sep 2020 22:24:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=amacapital-net.20150623.gappssmtp.com header.i=@amacapital-net.20150623.gappssmtp.com header.b="JGo5Ok3U" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726795AbgISWX5 (ORCPT ); Sat, 19 Sep 2020 18:23:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726749AbgISWX4 (ORCPT ); Sat, 19 Sep 2020 18:23:56 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95217C0613D3 for ; Sat, 19 Sep 2020 15:23:56 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id x123so5827418pfc.7 for ; Sat, 19 Sep 2020 15:23:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amacapital-net.20150623.gappssmtp.com; s=20150623; h=content-transfer-encoding:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to; bh=Zt+NcwFtW78Ml5fABVrawYmyBt1OY97jVqUspSuSzso=; b=JGo5Ok3UQlPkC13DKOsYdJnfzq73atFfYisEM+Hwumxj0suTBGssb+VorpwmGSdeCs bcXUpcZN25SMMCskSZLqiZtD4YDbCCmBpaZRkf/XvoBbu4chMl2XKMFhFG1ni8TPjold u1MXw/S5l0zIP2gSmcy2WrK2PhaeRtThtZVCQ2dBve9yiyZAijqQYE96b0yFOHC1wqdZ 7hEKxxWuktu0haCnifIZQak4CZt8BJYl2PwWFDdP87EmsRRAJSorXT5hINrPIcaUrT6Y ZGcKD1NJTEIknksw7U+45Z60Vnnj162xs4+yz1Qx9fnmzqSyx2F/YY69FVIp1XlYNq6/ 4JRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:content-transfer-encoding:from:mime-version :subject:date:message-id:references:cc:in-reply-to:to; bh=Zt+NcwFtW78Ml5fABVrawYmyBt1OY97jVqUspSuSzso=; b=GJl0sFagpygVa6KrxQUYLa47sE95jWMR7NbZYUcn3P3UWF4/qYXaxLn1kugZa2P4YX 6/yIHK7Ss6KNp7FxMRD4o5CV3QIvhaV+AvKoldA9POjPOXVTnse7sDHWaXvcBB+nvlua AGQ9J6IdgEHw0uSD7OQ86fUtrSLXKe2JWu4O9ZpzqitPJL/gq2aR7ag9NMenAKtYLFU7 yBsQ81U3IWRcFZ0pUQgW/llUTQeekQnjauURBvCk0Ux2BrL/oAdKCViMnu7eLVoGxH7s A7ZitqK5b3EC0fh9yFvGgYGJCfFQiAWscrFdvE4egE83P6thG6ogrqTsgXAoXpD5CTM2 4tBg== X-Gm-Message-State: AOAM532OgU5EF4dkbqZ4iybtW3VbPX8oJxL1sHWcVoX+T3K5zaSnzFDM ja2grqd3TIxcidWgdPUPBEtWkg== X-Google-Smtp-Source: ABdhPJzQlxXV5m1vFuZ7oLLvJBaRav6dyPvh+IWASrFhojswDAtpJrULIu1W68E3I7AE9Ae7seCzYQ== X-Received: by 2002:aa7:9583:0:b029:142:2501:396a with SMTP id z3-20020aa795830000b02901422501396amr21664408pfj.47.1600554235950; Sat, 19 Sep 2020 15:23:55 -0700 (PDT) Received: from localhost.localdomain ([2601:646:c200:1ef2:e9da:b923:b529:3349]) by smtp.gmail.com with ESMTPSA id gb17sm6607151pjb.15.2020.09.19.15.23.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 19 Sep 2020 15:23:55 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Andy Lutomirski Mime-Version: 1.0 (1.0) Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Date: Sat, 19 Sep 2020 15:23:54 -0700 Message-Id: References: <20200919220920.GI3421308@ZenIV.linux.org.uk> 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 In-Reply-To: <20200919220920.GI3421308@ZenIV.linux.org.uk> To: Al Viro X-Mailer: iPhone Mail (18A373) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org > On Sep 19, 2020, at 3:09 PM, Al Viro wrote: >=20 > =EF=BB=BFOn Fri, Sep 18, 2020 at 05:16:15PM +0200, Christoph Hellwig wrote= : >>> On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote: >>> Said that, why not provide a variant that would take an explicit >>> "is it compat" argument and use it there? And have the normal >>> one pass in_compat_syscall() to that... >>=20 >> That would help to not introduce a regression with this series yes. >> But it wouldn't fix existing bugs when io_uring is used to access >> read or write methods that use in_compat_syscall(). One example that >> I recently ran into is drivers/scsi/sg.c. >=20 > So screw such read/write methods - don't use them with io_uring. > That, BTW, is one of the reasons I'm sceptical about burying the > decisions deep into the callchain - we don't _want_ different > data layouts on read/write depending upon the 32bit vs. 64bit > caller, let alone the pointer-chasing garbage that is /dev/sg. Well, we could remove in_compat_syscall(), etc and instead have an implicit p= arameter in DEFINE_SYSCALL. Then everything would have to be explicit. Thi= s would probably be a win, although it could be quite a bit of work.= From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Lutomirski Date: Sat, 19 Sep 2020 22:23:54 +0000 Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="ibm852" Content-Transfer-Encoding: base64 List-Id: References: <20200919220920.GI3421308@ZenIV.linux.org.uk> In-Reply-To: <20200919220920.GI3421308@ZenIV.linux.org.uk> 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 Cj4gT24gU2VwIDE5LCAyMDIwLCBhdCAzOjA5IFBNLCBBbCBWaXJvIDx2aXJvQHplbml2LmxpbnV4 Lm9yZy51az4gd3JvdGU6Cj4gCj4g77u/T24gRnJpLCBTZXAgMTgsIDIwMjAgYXQgMDU6MTY6MTVQ TSArMDIwMCwgQ2hyaXN0b3BoIEhlbGx3aWcgd3JvdGU6Cj4+PiBPbiBGcmksIFNlcCAxOCwgMjAy MCBhdCAwMjo1ODoyMlBNICswMTAwLCBBbCBWaXJvIHdyb3RlOgo+Pj4gU2FpZCB0aGF0LCB3aHkg bm90IHByb3ZpZGUgYSB2YXJpYW50IHRoYXQgd291bGQgdGFrZSBhbiBleHBsaWNpdAo+Pj4gImlz IGl0IGNvbXBhdCIgYXJndW1lbnQgYW5kIHVzZSBpdCB0aGVyZT8gIEFuZCBoYXZlIHRoZSBub3Jt YWwKPj4+IG9uZSBwYXNzIGluX2NvbXBhdF9zeXNjYWxsKCkgdG8gdGhhdC4uLgo+PiAKPj4gVGhh dCB3b3VsZCBoZWxwIHRvIG5vdCBpbnRyb2R1Y2UgYSByZWdyZXNzaW9uIHdpdGggdGhpcyBzZXJp ZXMgeWVzLgo+PiBCdXQgaXQgd291bGRuJ3QgZml4IGV4aXN0aW5nIGJ1Z3Mgd2hlbiBpb191cmlu ZyBpcyB1c2VkIHRvIGFjY2Vzcwo+PiByZWFkIG9yIHdyaXRlIG1ldGhvZHMgdGhhdCB1c2UgaW5f Y29tcGF0X3N5c2NhbGwoKS4gIE9uZSBleGFtcGxlIHRoYXQKPj4gSSByZWNlbnRseSByYW4gaW50 byBpcyBkcml2ZXJzL3Njc2kvc2cuYy4KPiAKPiBTbyBzY3JldyBzdWNoIHJlYWQvd3JpdGUgbWV0 aG9kcyAtIGRvbid0IHVzZSB0aGVtIHdpdGggaW9fdXJpbmcuCj4gVGhhdCwgQlRXLCBpcyBvbmUg b2YgdGhlIHJlYXNvbnMgSSdtIHNjZXB0aWNhbCBhYm91dCBidXJ5aW5nIHRoZQo+IGRlY2lzaW9u cyBkZWVwIGludG8gdGhlIGNhbGxjaGFpbiAtIHdlIGRvbid0IF93YW50XyBkaWZmZXJlbnQKPiBk YXRhIGxheW91dHMgb24gcmVhZC93cml0ZSBkZXBlbmRpbmcgdXBvbiB0aGUgMzJiaXQgdnMuIDY0 Yml0Cj4gY2FsbGVyLCBsZXQgYWxvbmUgdGhlIHBvaW50ZXItY2hhc2luZyBnYXJiYWdlIHRoYXQg aXMgL2Rldi9zZy4KCldlbGwsIHdlIGNvdWxkIHJlbW92ZSBpbl9jb21wYXRfc3lzY2FsbCgpLCBl dGMgYW5kIGluc3RlYWQgaGF2ZSBhbiBpbXBsaWNpdCBwYXJhbWV0ZXIgaW4gREVGSU5FX1NZU0NB TEwuICBUaGVuIGV2ZXJ5dGhpbmcgd291bGQgaGF2ZSB0byBiZSBleHBsaWNpdC4gIFRoaXMgd291 bGQgcHJvYmFibHkgYmUgYSB3aW4sIGFsdGhvdWdoIGl0IGNvdWxkIGJlIHF1aXRlIGEgYml0IG9m IHdvcmsu From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Lutomirski Date: Sat, 19 Sep 2020 22:23:54 +0000 Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-Id: List-Id: References: <20200919220920.GI3421308@ZenIV.linux.org.uk> In-Reply-To: <20200919220920.GI3421308@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable 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 > On Sep 19, 2020, at 3:09 PM, Al Viro wrote: >=20 > =EF=BB=BFOn Fri, Sep 18, 2020 at 05:16:15PM +0200, Christoph Hellwig wrot= e: >>> On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote: >>> Said that, why not provide a variant that would take an explicit >>> "is it compat" argument and use it there? And have the normal >>> one pass in_compat_syscall() to that... >>=20 >> That would help to not introduce a regression with this series yes. >> But it wouldn't fix existing bugs when io_uring is used to access >> read or write methods that use in_compat_syscall(). One example that >> I recently ran into is drivers/scsi/sg.c. >=20 > So screw such read/write methods - don't use them with io_uring. > That, BTW, is one of the reasons I'm sceptical about burying the > decisions deep into the callchain - we don't _want_ different > data layouts on read/write depending upon the 32bit vs. 64bit > caller, let alone the pointer-chasing garbage that is /dev/sg. Well, we could remove in_compat_syscall(), etc and instead have an implicit= parameter in DEFINE_SYSCALL. Then everything would have to be explicit. = This would probably be a win, although it could be quite a bit of work. 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charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Andy Lutomirski Mime-Version: 1.0 (1.0) Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Date: Sat, 19 Sep 2020 15:23:54 -0700 Message-Id: References: <20200919220920.GI3421308@ZenIV.linux.org.uk> In-Reply-To: <20200919220920.GI3421308@ZenIV.linux.org.uk> To: Al Viro X-Mailer: iPhone Mail (18A373) 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@kvack.org, linux-mips@vger.kernel.org, David Howells , linux-mm@kvack.org, keyrings@vger.kernel.org, sparclinux@vger.kernel.org, Christoph Hellwig , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, x86@kernel.org, Arnd Bergmann , linux-block@vger.kernel.org, io-uring@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jens Axboe , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" > On Sep 19, 2020, at 3:09 PM, Al Viro wrote: >=20 > =EF=BB=BFOn Fri, Sep 18, 2020 at 05:16:15PM +0200, Christoph Hellwig wrote= : >>> On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote: >>> Said that, why not provide a variant that would take an explicit >>> "is it compat" argument and use it there? And have the normal >>> one pass in_compat_syscall() to that... >>=20 >> That would help to not introduce a regression with this series yes. >> But it wouldn't fix existing bugs when io_uring is used to access >> read or write methods that use in_compat_syscall(). One example that >> I recently ran into is drivers/scsi/sg.c. >=20 > So screw such read/write methods - don't use them with io_uring. > That, BTW, is one of the reasons I'm sceptical about burying the > decisions deep into the callchain - we don't _want_ different > data layouts on read/write depending upon the 32bit vs. 64bit > caller, let alone the pointer-chasing garbage that is /dev/sg. Well, we could remove in_compat_syscall(), etc and instead have an implicit p= arameter in DEFINE_SYSCALL. Then everything would have to be explicit. Thi= s would probably be a win, although it could be quite a bit of work.= 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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 CBBC7C43463 for ; Sat, 19 Sep 2020 22:25:21 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 77E4321741 for ; Sat, 19 Sep 2020 22:25:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="K9YViZ81"; 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Sat, 19 Sep 2020 15:23:55 -0700 (PDT) From: Andy Lutomirski Mime-Version: 1.0 (1.0) Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Date: Sat, 19 Sep 2020 15:23:54 -0700 Message-Id: References: <20200919220920.GI3421308@ZenIV.linux.org.uk> In-Reply-To: <20200919220920.GI3421308@ZenIV.linux.org.uk> To: Al Viro X-Mailer: iPhone Mail (18A373) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200919_182358_427831_9174CC7B X-CRM114-Status: GOOD ( 18.13 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-aio@kvack.org, linux-mips@vger.kernel.org, David Howells , linux-mm@kvack.org, keyrings@vger.kernel.org, sparclinux@vger.kernel.org, Christoph Hellwig , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, x86@kernel.org, Arnd Bergmann , linux-block@vger.kernel.org, io-uring@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jens Axboe , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org Content-Type: text/plain; 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