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=-0.7 required=3.0 tests=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 55B3BC432C0 for ; Mon, 25 Nov 2019 03:38:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 30C5020748 for ; Mon, 25 Nov 2019 03:38:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726939AbfKYDii convert rfc822-to-8bit (ORCPT ); Sun, 24 Nov 2019 22:38:38 -0500 Received: from smtpbg513.qq.com ([203.205.250.40]:49083 "EHLO smtpbg.qq.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726921AbfKYDii (ORCPT ); Sun, 24 Nov 2019 22:38:38 -0500 X-QQ-mid: Xesmtp4t1574652810tu3b6sl0s Received: from [172.16.31.194] (unknown [218.76.23.26]) by esmtp4.qq.com (ESMTP) with id ; Mon, 25 Nov 2019 11:33:29 +0800 (CST) X-QQ-SSF: 00000000000000B0SF101F00000000K X-QQ-FEAT: asOxXDmQmvCBOsN02paYPJsp9+UmuXyQpi1wakvYUIFaJ51jhQrib6Z5CGWFl hTawHrP/R7BTKcWqNB9N3hbqLx/3BWCl3BX//vKzDI0uHChhr+NpQoYIoZq5v73K7/DEd2N ObCvOcDV5HcssEKZsFofrFh5lsqz5wgsJYftd1Nxcir5SFo+voS31hzXo/UvKlF/Ul4UjjC Pgyu8jYBgGxRfMh5U5fyTPt5DIQNRdqr2cJ2X8TQyDfxPHjkYf9+1e5VbauVUo4DWH5/qLJ hhpcY6DnYGxflU4Yd89yjGorosv1Muk/j3JThlGZ8M+xkDHr1QsTK5nA4= X-QQ-GoodBg: 0 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3601.0.10\)) Subject: Re: [PATCH v2] io_uring: fix dead-hung for non-iter fixed rw From: Jackie Liu In-Reply-To: <838a574f-e118-cda2-5412-c21af85c512b@kernel.dk> Date: Mon, 25 Nov 2019 11:33:26 +0800 Cc: Pavel Begunkov , io-uring@vger.kernel.org Content-Transfer-Encoding: 8BIT Message-Id: <107FEF05-A0E6-4E81-BD0A-BB360CD7F628@byteisland.com> References: <620023b272fef0fd76d0f91ff1876fa64864caa6.1574585281.git.asml.silence@gmail.com> <6a2fcf67-1267-a02a-98ce-435bbb2ca9bb@kernel.dk> <838a574f-e118-cda2-5412-c21af85c512b@kernel.dk> To: Jens Axboe X-Mailer: Apple Mail (2.3601.0.10) X-QQ-SENDSIZE: 520 Feedback-ID: Xesmtp:byteisland.com:bgweb:bgweb4 Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org > 2019年11月25日 10:38，Jens Axboe 写道： > > 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. > For test/stdout is PASS. Tested-by: Jackie Liu But test/accept-link and test/fixed-link failed in for-5.5/io_uring-post branch. that is expect? -- Jackie Liu