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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 6708AC433E0 for ; Mon, 1 Mar 2021 14:20:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2796B64DFB for ; Mon, 1 Mar 2021 14:20:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232983AbhCAOT6 (ORCPT ); Mon, 1 Mar 2021 09:19:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:51732 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232807AbhCAOTy (ORCPT ); Mon, 1 Mar 2021 09:19:54 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id CC28C64E07; Mon, 1 Mar 2021 14:19:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614608354; bh=k1UvY5aGECSBschfIZbptzWuvhL5cuyW0lixGCaxFHg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IBVrvHn70IusfxbNTfaUa4EiDWHh5ycOe9o0R9NXJzWU2yc0dFLuSDmH85Xb0+mHm KV6VtIHyxBhjug7yQ738Qs4J81vnM3F9ADrUYza04xV/A0NV/2riOyKL69LsFi2rcs QQ96bdbJ4YVP+e/xYB+SuZhyWbzjGVr5ZoVib92I= Date: Mon, 1 Mar 2021 15:19:11 +0100 From: Greg KH To: Lee Jones Cc: Xiaoming Ni , linux-kernel@vger.kernel.org, stable@vger.kernel.org, sashal@kernel.org, tglx@linutronix.de, wangle6@huawei.com, zhengyejian1@huawei.com Subject: Re: [PATCH 4.9.258] futex: fix dead code in attach_to_pi_owner() Message-ID: References: <20210224100923.51315-1-nixiaoming@huawei.com> <20210225091738.GC641347@dell> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210225091738.GC641347@dell> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Thu, Feb 25, 2021 at 09:17:38AM +0000, Lee Jones wrote: > On Wed, 24 Feb 2021, Xiaoming Ni wrote: > > > The handle_exit_race() function is defined in commit 9c3f39860367 > > ("futex: Cure exit race"), which never returns -EBUSY. This results > > in a small piece of dead code in the attach_to_pi_owner() function: > > > > int ret = handle_exit_race(uaddr, uval, p); /* Never return -EBUSY */ > > ... > > if (ret == -EBUSY) > > *exiting = p; /* dead code */ > > > > The return value -EBUSY is added to handle_exit_race() in upsteam > > commit ac31c7ff8624409 ("futex: Provide distinct return value when > > owner is exiting"). This commit was incorporated into v4.9.255, before > > the function handle_exit_race() was introduced, whitout Modify > > handle_exit_race(). > > > > To fix dead code, extract the change of handle_exit_race() from > > commit ac31c7ff8624409 ("futex: Provide distinct return value when owner > > is exiting"), re-incorporated. > > > > Fixes: 9c3f39860367 ("futex: Cure exit race") > > Cc: stable@vger.kernel.org # v4.9.258 > > Signed-off-by: Xiaoming Ni > > --- > > kernel/futex.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > To clarify, this is not a wholesale back-port from Mainline. > > It takes the remaining functional snippet of: > > ac31c7ff8624409 ("futex: Provide distinct return value when owner is exiting") > > ... and is the correct fix for this issue. > > Reviewed-by: Lee Jones Thanks, now queued up. greg k-h