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=ham 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 9B7D3C4363A for ; Tue, 27 Oct 2020 00:09:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F0A4120754 for ; Tue, 27 Oct 2020 00:09:11 +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" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F0A4120754 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4A85E6B0070; Mon, 26 Oct 2020 20:09:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 42A076B006C; Mon, 26 Oct 2020 20:09:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F15B6B006E; Mon, 26 Oct 2020 20:09:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0153.hostedemail.com [216.40.44.153]) by kanga.kvack.org (Postfix) with ESMTP id 003BA6B005C for ; Mon, 26 Oct 2020 20:09:10 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 9C049180AD802 for ; Tue, 27 Oct 2020 00:09:10 +0000 (UTC) X-FDA: 77415770460.30.shame59_17141ad27277 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin30.hostedemail.com (Postfix) with ESMTP id 81BBF180B3AA7 for ; Tue, 27 Oct 2020 00:09:10 +0000 (UTC) X-HE-Tag: shame59_17141ad27277 X-Filterd-Recvd-Size: 5626 Received: from mail-pg1-f196.google.com (mail-pg1-f196.google.com [209.85.215.196]) by imf35.hostedemail.com (Postfix) with ESMTP for ; Tue, 27 Oct 2020 00:09:09 +0000 (UTC) Received: by mail-pg1-f196.google.com with SMTP id 15so281998pgd.12 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=Fp6sHjTer3Pi3xsWoKgTUh+IwUOsR6J7WJ2JyVXNUIPSPGUbTkeSWTXimH0l5VpdY9 cL6VRv30ixfiYCeg1X8IkjwbsxTwtEPZ+UEpfon88hDz9mhZ5I6WX0HLpMLgRZsWhMTw l8L2R7PMKfknr6X9PciKpWGtz7zqkSYNxBR/tfUHRLxyeNBCLkJobLuYeYH2AdDPlbi2 t23rjuyAbWAvwgmioJK1tyoDiXpjvJOMq7JzsCZ5ZazmCh9bDuCyg8s9jI521m86cvYY huhy2mQCpmFGa0/E+A8shJIHKB2xbbAHeHgejUnb9jDBH5uPJHDOfBchhrVgTwd9wCHI DJmA== X-Gm-Message-State: AOAM530G1WwrvYQ5ANDLVYtq6rpIemUacVh+I/ZUNDTNDibSTWOOx5a7 VYryb1TvvzzO0padYaZhwmHhRw== 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 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 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