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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, 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 D9773C433E0 for ; Thu, 11 Mar 2021 03:49:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D9B9364E20 for ; Thu, 11 Mar 2021 03:49:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230231AbhCKDtD (ORCPT ); Wed, 10 Mar 2021 22:49:03 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:13500 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230052AbhCKDtA (ORCPT ); Wed, 10 Mar 2021 22:49:00 -0500 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4Dwvyk52MpzrTlR; Thu, 11 Mar 2021 11:47:10 +0800 (CST) Received: from [10.67.110.218] (10.67.110.218) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.498.0; Thu, 11 Mar 2021 11:48:52 +0800 Subject: Re: [PATCH 4.4 0/3] Backport patch series to update Futex from 4.9 To: Greg KH CC: , , , , , , , References: <20210309030605.3295183-1-zhengyejian1@huawei.com> From: "Zhengyejian (Zetta)" Message-ID: Date: Thu, 11 Mar 2021 11:48:52 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.110.218] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On 2021/3/9 18:41, Greg KH wrote: > On Tue, Mar 09, 2021 at 11:06:02AM +0800, Zheng Yejian wrote: >> Lee sent a patchset to update Futex for 4.9, see https://www.spinics.net/lists/stable/msg443081.html, >> Then Xiaoming sent a follow-up patch for it, see https://lore.kernel.org/lkml/20210225093120.GD641347@dell/. >> >> These patchsets may also resolve following issues in 4.4.260 which have been reported in 4.9, >> see https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/?h=linux-4.4.y&id=319f66f08de1083c1fe271261665c209009dd65a >> > /* >> > * The task is on the way out. When the futex state is >> > * FUTEX_STATE_DEAD, we know that the task has finished >> > * the cleanup: >> > */ >> > int ret = (p->futex_state = FUTEX_STATE_DEAD) ? -ESRCH : -EAGAIN; >> >> Here may be: >> int ret = (p->futex_state == FUTEX_STATE_DEAD) ? -ESRCH : -EAGAIN; >> >> > raw_spin_unlock_irq(&p->pi_lock); >> > /* >> > * If the owner task is between FUTEX_STATE_EXITING and >> > * FUTEX_STATE_DEAD then store the task pointer and keep >> > * the reference on the task struct. The calling code will >> > * drop all locks, wait for the task to reach >> > * FUTEX_STATE_DEAD and then drop the refcount. This is >> > * required to prevent a live lock when the current task >> > * preempted the exiting task between the two states. >> > */ >> > if (ret == -EBUSY) >> >> And here, the variable "ret" may only be "-ESRCH" or "-EAGAIN", but not "-EBUSY". >> >> > *exiting = p; >> > else >> > put_task_struct(p); >> >> Since 074e7d515783 ("futex: Ensure the correct return value from futex_lock_pi()") has >> been merged in 4.4.260, I send the remain 3 patches. > > There already are 2 futex patches in the 4.4.y stable queue, do those > not resolve these issues for you? I think that 2 futex patches in 4.4 stable queue are fixing other issues: futex-fix-irq-self-deadlock-and-satisfy-assertion.patch futex-fix-spin_lock-spin_unlock_irq-imbalance.patch But I am not very sure if there are any lock conflicts between that 2 patches and this 3 patches. > > If not, please resend this series with the needed git commit ids added to > them. I have add that information and sent a "v2" patchset.