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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, 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 98AA6C432C3 for ; Mon, 25 Nov 2019 02:38:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 68D712073F for ; Mon, 25 Nov 2019 02:38:48 +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="PJMCPg1X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726931AbfKYCis (ORCPT ); Sun, 24 Nov 2019 21:38:48 -0500 Received: from mail-pj1-f67.google.com ([209.85.216.67]:40454 "EHLO mail-pj1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726891AbfKYCir (ORCPT ); Sun, 24 Nov 2019 21:38:47 -0500 Received: by mail-pj1-f67.google.com with SMTP id ep1so5881858pjb.7 for ; Sun, 24 Nov 2019 18:38:46 -0800 (PST) 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=h4g3p0r/URLgceda6oneY+W+5GgwJK5bezfgsk7dapU=; b=PJMCPg1XEAU/Shf5pPha06+luSJfqiPX3ETi/C4b+OiTjFq7hFo92mfvCN3aE44kaV OlBwWcpyGVHSGj7Jz6x3KgZXSzYVMUYj9BekZt5EVoGzzGPbQRUycLPlXeAdmlMUdAJM 5IRW1DEqpldpErPFWP7jG8tShjtf3QUa8ehTgaKmyDs+ds7BlnlMpDSWoDZeJ3l2rSSc fkCvSyS/AqhGT+F1z1muJjFtYdBRoCYYUQbtgG0deiw3mAvgmtVxEP+NfoxIgrpb7m06 6FBAS5vyxdri5rAHHY5YUDIVY45o9HJIkCqUrXTAJRMv6rE/cOfH1I0dRZiKoscBjVEE e1XQ== 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=h4g3p0r/URLgceda6oneY+W+5GgwJK5bezfgsk7dapU=; b=jRrIb+F1X57nbUhfEyOxHC/JTdArQU9UWFLH1LSB/PA6P9bSoaxvx4ahhtY4Ssdvhr xjM8DL7fQQFsdkDU0jUoTQ74f858Ai/MgXu7ApGaYByXyiWQyErzWyC61fntR751WpNA CMEXV/m35o7LZhsprCUvayBof0jk1YQeixidc2BwtFuP+L9hkm4j5/cCJEsfRzZeiPjl MQF7NNOW8Z7NdELFsWo9+e7gbP61j0H0S0zOwKRBBM9QwfQ+pGaunlfuUEqlNWw4VIYY StWW25a0RMWG0SmL9rkl542zXOtWsAq4MkYk6xzW434uEejyt5SUvuvlFI1vOnnlZtS7 tRmQ== X-Gm-Message-State: APjAAAXJcHLb+/Yjvx1RU1PXkzpPnDoxRidFeTupuDHSRITCnyvxja6s s10HdStvBTZlzAhSJea48stO/EEEKyw93w== X-Google-Smtp-Source: APXvYqx3XSGhcILtSjukwezpvkZt4T502tse6oTVccnDyfSCk/gXJojI6d6De2PqyM3aAzl4QUe1Hw== X-Received: by 2002:a17:90a:8995:: with SMTP id v21mr36167806pjn.109.1574649525526; Sun, 24 Nov 2019 18:38:45 -0800 (PST) Received: from [192.168.1.188] ([66.219.217.79]) by smtp.gmail.com with ESMTPSA id a23sm5918431pjv.26.2019.11.24.18.38.43 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 24 Nov 2019 18:38:44 -0800 (PST) Subject: Re: [PATCH v2] io_uring: fix dead-hung for non-iter fixed rw To: Jackie Liu , Pavel Begunkov Cc: io-uring@vger.kernel.org References: <620023b272fef0fd76d0f91ff1876fa64864caa6.1574585281.git.asml.silence@gmail.com> <6a2fcf67-1267-a02a-98ce-435bbb2ca9bb@kernel.dk> From: Jens Axboe Message-ID: <838a574f-e118-cda2-5412-c21af85c512b@kernel.dk> Date: Sun, 24 Nov 2019 19:38:42 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 11/24/19 5:43 PM, Jackie Liu wrote: > > >> 2019年11月25日 01:52，Pavel Begunkov 写道： >> >> On 24/11/2019 20:10, Jens Axboe wrote: >>> On 11/24/19 1:58 AM, Pavel Begunkov wrote: >>>> Read/write requests to devices without implemented read/write_iter >>>> using fixed buffers causes general protection fault, which totally >>>> hangs a machine. >>>> >>>> io_import_fixed() initialises iov_iter with bvec, but loop_rw_iter() >>>> accesses it as iovec, so dereferencing random address. >>>> >>>> kmap() page by page in this case >>> >>> This looks good to me, much cleaner/simpler. I've added a few pipe fixed >>> buffer tests to liburing as well. Didn't crash for me, but obvious >>> garbage coming out. I've flagged this for stable as well. >>> >> The problem I have is that __user pointer is meant to be checked >> for not being a kernel address. I suspect, it could fail in some >> device, which double checks the pointer after vfs (e.g. using access_ok()). >> Am I wrong? Not a fault at least... >> >> #define access_ok(...) __range_not_ok(addr, user_addr_max()); >> >> BTW, is there anybody testing it for non x86-64 arch? >> > > I have some aarch64 platform, What test do you want me to do? A basic one to try would be: axboe@x1:/home/axboe/git/liburing $ test/stdout This is a pipe test This is a fixed pipe test But in general I'd just run make runtests in the liburing directory and go through all of them. -- Jens Axboe