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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C0454C74A21 for ; Wed, 10 Jul 2019 15:33:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 997892087F for ; Wed, 10 Jul 2019 15:33:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727165AbfGJPdd convert rfc822-to-8bit (ORCPT ); Wed, 10 Jul 2019 11:33:33 -0400 Received: from smtpbgsg2.qq.com ([54.254.200.128]:45646 "EHLO smtpbgsg2.qq.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727063AbfGJPdc (ORCPT ); Wed, 10 Jul 2019 11:33:32 -0400 X-QQ-mid: bizesmtp24t1562772799tvp6zkyz Received: from [192.168.31.139] (unknown [175.10.88.112]) by esmtp10.qq.com (ESMTP) with id ; Wed, 10 Jul 2019 23:33:18 +0800 (CST) X-QQ-SSF: 00400000002000Q0WO70000A0000000 X-QQ-FEAT: w8rTskylU5YMmCAYbtHdn/MUGLbHtgl8Y9fB6Qu1BJRt+JTFGWrTi2S0uURK3 CdZBdSNeih2AFiCnK4vnt+YnGBAVn2uxcYEo1nJqFfNnR7O43L5T+WsogZ8OZ39h9+nCNz4 WY9dAYg4bgzTHErOCnAQWR0XpQtacUx7Bjfl3WXlyIUMS3WOtb1OnRLGI3zs379Ed3ZROvJ dmxTgynT0zaOFpz4usH/N2oTSg3W0YuQ23b450AVrcebEvzFi3hxtH/jLXtV+gFmdC7sBpg B5ELOcYHi0yLGD1Vqu12CuvoLEtokk2y0XFYyp83IYb+Ozkh90tncHrMHcAGjWYsfRJNdET 3BQvChK X-QQ-GoodBg: 2 Content-Type: text/plain; charset=gb2312 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Subject: Re: [PATCH] io_uring: fix stuck problem caused by potential memory alloc failure From: JackieLiu In-Reply-To: <25691b9f-8c0f-0d19-d1db-4c4ce6dfb5a9@kernel.dk> Date: Wed, 10 Jul 2019 23:33:18 +0800 Cc: linux-block@vger.kernel.org Content-Transfer-Encoding: 8BIT Message-Id: <7E6A5863-5948-45B2-A7B7-C0CAEB8EDD8C@kylinos.cn> References: <20190710083558.5940-1-liuyun01@kylinos.cn> <25691b9f-8c0f-0d19-d1db-4c4ce6dfb5a9@kernel.dk> To: Jens Axboe X-Mailer: Apple Mail (2.3445.104.11) X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:kylinos.cn:qybgforeign:qybgforeign2 X-QQ-Bgrelay: 1 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Thank you for pointing out. I haven't had time to pay attention to the new features of sqe links. When I was debugging another stuck problem, I found that there was no free the reference count, so I sent the patch about this. Anyway, if necessary, I will resend the patch again, with your rewritten comments. > 在 2019年7月10日，21:57，Jens Axboe 写道： > > On 7/10/19 2:35 AM, Jackie Liu wrote: >> when io_req_defer alloc memory failed, it will be return -EAGAIN. >> But io_submit_sqe cannot be returned immediately because the reference >> count for req is still hold. we should be clean it. > > Looks like this actually got fixed in my for-5.3/io_uring branch which > I haven't pushed out yet. Once that's in, I'd suggest we send yours to > stable separately. Probably change the wording to: > > When io_req_defer alloc memory fails, it will be -EAGAIN. But > io_submit_sqe cannot return immediately because the reference count for > req is still held. Ensure that we free it. > > -- > Jens Axboe > >