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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 ABD1FC433DF for ; Wed, 27 May 2020 13:52:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 895272078C for ; Wed, 27 May 2020 13:52:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590587539; bh=P1fXzehRUxYttHKGmyhAdhyhRlmS5Hp/HQQW6zPByp0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Cc4JCcpMVxsH441KNbpiTQJJmnalr58XcxKUYdBNZSP8wC4uKpNnd5TdivNglpvYV W0YgeRL7RHBZNsvNT3M0rKXSQR6WRmJHIeZQL2UiKPq1FurPsJrYVT34CkRGvf7sIe mQ4dipNV+VLYK/zPfm5EtYEWOqjNEqc8wOp519eM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388916AbgE0NwT (ORCPT ); Wed, 27 May 2020 09:52:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388899AbgE0NwS (ORCPT ); Wed, 27 May 2020 09:52:18 -0400 Received: from mail-qv1-xf43.google.com (mail-qv1-xf43.google.com [IPv6:2607:f8b0:4864:20::f43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44241C08C5C1 for ; Wed, 27 May 2020 06:52:18 -0700 (PDT) Received: by mail-qv1-xf43.google.com with SMTP id dh1so11123694qvb.13 for ; Wed, 27 May 2020 06:52:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=yCfXCQLnkmmliUl6o46VN/g4F3+m5D5qyYWprcFsdzw=; b=ILvc1MCIouRXqf4iMkoTsgwlu7e2DkUvMWMjEiGuqm1VIwOM0WBU6DMMVW9Od645rK /pZeylfCuKv6HIpwvfz8wkiIxqofuIV4vkyNmTXa4TuVCj0mUjuytwisQHxAYT9VTyZ2 FejPrUZdNHX1fz1DbokFY43xQ358a9FOE6/UFU7QeajQcP5c4NK4S7lfpGBgV+tnvMwI 37Bv7D7l1v1XM8RSMRKx4bJUYmrcbS2LsVeQ9wkbeMGQehTPMpG6olFCP6kjJeWUedgg umqBLiHNNsQejZmSjAR96NKgjbDKZSKTkEcbfWpQEogzYiYgG1eCIVa22CY7nyEEeD/l KfCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=yCfXCQLnkmmliUl6o46VN/g4F3+m5D5qyYWprcFsdzw=; b=lNNduU6fGEwqFOj6sYZa/DE0SoWKEnPsrn0zA3fWJL3XEjl2IS5aCJaMo7hRSd5jKs ngefj3uLOhuEJc3zX+/eIZvU2W9AmGVI04I8oaz5WlZYBCNSVjXQpty5MNNLG/dWCsqG 0b8rFv1pP3ecTfPn0yMkz7hfPa4IpXuwKIvTJS5dFif/vFE1W7rmifUk9OkXYgy0Mrjf HkvY5+XqZY+GDTOAx3ExXt6j8QeO9HY1pkQ6JmOYvkJsffwLwvdMXxadb91sd+AlpFNJ 7PVbSMFfyIPxooaa8FzvCiJbyRLqyJr49OEGOzy2dBSO5Y7Wj2wQsXkBzEaHkBR6Okc/ 5jSw== X-Gm-Message-State: AOAM533iKqU3xknHDM0PE+8AC7RL3IPbEmc1CkYwtCsykXfk2AwnCngU hAJZW1DD12GO1l6r1OhFmCZqKVfO X-Google-Smtp-Source: ABdhPJzr/BZ/dF51pigBmbkNJyTIcg4vbPHWZn0hbMeMyd7Ix1aB8FmUHZYfNi6GTwNirRW3pqagGg== X-Received: by 2002:a0c:fe03:: with SMTP id x3mr24456859qvr.18.1590587537097; Wed, 27 May 2020 06:52:17 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:74a]) by smtp.gmail.com with ESMTPSA id 5sm2337501qko.14.2020.05.27.06.52.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 May 2020 06:52:16 -0700 (PDT) Date: Wed, 27 May 2020 09:52:14 -0400 From: Tejun Heo To: qiang.zhang@windriver.com Cc: jiangshanlai@gmail.com, markus.elfring@web.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5] workqueue: Remove unnecessary kfree() call in rcu_free_wq() Message-ID: <20200527135214.GI83516@mtj.thefacebook.com> References: <20200527075715.36849-1-qiang.zhang@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200527075715.36849-1-qiang.zhang@windriver.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 27, 2020 at 03:57:15PM +0800, qiang.zhang@windriver.com wrote: > From: Zhang Qiang > > The data structure member "wq->rescuer" was reset to a null pointer > in one if branch. It was passed to a call of the function "kfree" > in the callback function "rcu_free_wq" (which was eventually executed). > The function "kfree" does not perform more meaningful data processing > for a passed null pointer (besides immediately returning from such a call). > Thus delete this function call which became unnecessary with the referenced > software update. > > Fixes: def98c84b6cd ("workqueue: Fix spurious sanity check failures in destroy_workqueue()") > > Suggested-by: Markus Elfring > Signed-off-by: Zhang Qiang Applied to wq/for-5.8. Thanks. -- tejun