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=-10.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 19BA3C2D0A3 for ; Tue, 27 Oct 2020 00:09:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDB1120754 for ; Tue, 27 Oct 2020 00:09:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="DV6OWsJ8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2411321AbgJ0AJO (ORCPT ); Mon, 26 Oct 2020 20:09:14 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:44645 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2411093AbgJ0AJK (ORCPT ); Mon, 26 Oct 2020 20:09:10 -0400 Received: by mail-pf1-f196.google.com with SMTP id 133so1135635pfx.11 for ; Mon, 26 Oct 2020 17:09:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=LsJlRjdqhDVAHhw47g/atIos95r5K18qubNura+3fzc=; b=DV6OWsJ8YTis4RWe74HnMoSPHx2wnbbnih3F0P+HiF57IXnyKrAIcBplDa0TuQW0fe aii8O67y5CuNtSNcN0q+CPIFocqT+ma+us4RoqX4TC6tMgaGBGUnwVHQJ/N6qPZoUIZl N8PZQaTFtDJvhHp2KmiMn99XHribiQTVBqggOOByg6ZsC+AIdPeSZ7IIhzJWtbXj8peQ vUIkbSwJfbOC01KBcysHUuhejsj0lkLWHowENLgMtxCKJmsxzr5jKuNTtJsywdn514eT kI7wIhvyoH92wMz2QHWzCBEBrmMggfxor976qEm1YW1xHPKbqwPNkX7lWR3OAQC8rWrk OKFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=LsJlRjdqhDVAHhw47g/atIos95r5K18qubNura+3fzc=; b=qsxRMVWZvjXs6HZyqJPiBdTO2rSFXKjlOKPfkUt65tFDr897fKHVFuULmiRecHqR0l PQFltW5tAhG+ItInaR335dsOEzTjeo4bqzyutTranEAPTEpTFAqsCgqqMiaRNFn4gWN9 P2V9ctJgL9mmtvt8tDUgmdHocu9GCXtoKgvH3/tK1bkER6X3lV3hu6HBkYAZ5/dDP2JO njpVlQMntAvelOdFZrcyFRbcb+IItuEWg0/OosUY+pYi9blLfr0k5Mb2Pe2kOMgtoxiR lTVWrswxkfa7x+DboiFDffEmPC02EW4iwJgK+mYkD+A2f3kBvC4gGgM1t4YB3nOSQn0f 33dw== X-Gm-Message-State: AOAM531svMsDIMgqfYyiSY74XD6EmY00NdONkAJexFWfHfo/glwHy4XJ 6xz3o0O2c18OYxmg6h72PDVENg== X-Google-Smtp-Source: ABdhPJzyk1CokDb3PmPO6AYN5WbyxmkTO2goVocCEnl70vwlgJZot7evNIwwh9o3S+Q92QVwXSE2HA== X-Received: by 2002:a65:5c02:: with SMTP id u2mr18125891pgr.173.1603757348944; Mon, 26 Oct 2020 17:09:08 -0700 (PDT) Received: from [192.168.1.134] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id e16sm13676837pfh.45.2020.10.26.17.09.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 26 Oct 2020 17:09:08 -0700 (PDT) Subject: Re: [REGRESSION] mm: process_vm_readv testcase no longer works after compat_prcoess_vm_readv removed To: Al Viro Cc: Kyle Huey , open list , Christoph Hellwig , Robert O'Callahan , Andrew Morton , Arnd Bergmann , David Howells , "moderated list:ARM PORT" , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , 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, "open list:FILESYSTEMS (VFS and infrastructure)" , 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, Linus Torvalds References: <70d5569e-4ad6-988a-e047-5d12d298684c@kernel.dk> <20201027000521.GD3576660@ZenIV.linux.org.uk> From: Jens Axboe Message-ID: <0127a542-3f93-7bd0-e00d-4a0e49846c8f@kernel.dk> Date: Mon, 26 Oct 2020 18:09:06 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201027000521.GD3576660@ZenIV.linux.org.uk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 10/26/20 6:05 PM, Al Viro wrote: > On Mon, Oct 26, 2020 at 05:56:11PM -0600, Jens Axboe wrote: >> On 10/26/20 4:55 PM, Kyle Huey wrote: >>> A test program from the rr[0] test suite, vm_readv_writev[1], no >>> longer works on 5.10-rc1 when compiled as a 32 bit binary and executed >>> on a 64 bit kernel. The first process_vm_readv call (on line 35) now >>> fails with EFAULT. I have bisected this to >>> c3973b401ef2b0b8005f8074a10e96e3ea093823. >>> >>> It should be fairly straightforward to extract the test case from our >>> repository into a standalone program. >> >> Can you check with this applied? >> >> diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c >> index fd12da80b6f2..05676722d9cd 100644 >> --- a/mm/process_vm_access.c >> +++ b/mm/process_vm_access.c >> @@ -273,7 +273,8 @@ static ssize_t process_vm_rw(pid_t pid, >> return rc; >> if (!iov_iter_count(&iter)) >> goto free_iov_l; >> - iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r, false); >> + iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r, >> + in_compat_syscall()); > > _ouch_ > > There's a bug, all right, but I'm not sure that this is all there is > to it. For now it's probably the right fix, but... Consider the fun > trying to use that from 32bit process to access the memory of 64bit > one. IOW, we might want to add an explicit flag for "force 64bit > addresses/sizes in rvec". Ouch yes good point, nice catch. -- Jens Axboe