From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757931Ab3BGC3H (ORCPT ); Wed, 6 Feb 2013 21:29:07 -0500 Received: from mail-qe0-f52.google.com ([209.85.128.52]:57769 "EHLO mail-qe0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752179Ab3BGC3D (ORCPT ); Wed, 6 Feb 2013 21:29:03 -0500 MIME-Version: 1.0 In-Reply-To: <87k3qksw1n.fsf@sejong.aot.lge.com> References: <20130206184749.GB2875@htj.dyndns.org> <87k3qksw1n.fsf@sejong.aot.lge.com> Date: Wed, 6 Feb 2013 18:29:01 -0800 X-Google-Sender-Auth: H1ROX4uZJZDfRF0Z9j_6aysdy6M Message-ID: Subject: Re: [PATCH 2/3] stop_machine: dequeue work before signal completion From: Tejun Heo To: Namhyung Kim Cc: Hillf Danton , Rusty Russell , Andrew Morton , Ingo Molnar , LKML Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Wed, Feb 6, 2013 at 6:21 PM, Namhyung Kim wrote: >> Why does this matter? It's inside spinlock. What's being made better >> by this change? > > IIUC the work should be deleted from the list, otherwise it'd trigger > BUG_ON when the cpu gets online again. Ah, okay, the original code was missing list_del_init(), so we end up with trashy work list if CPU goes down while there are pending work items which will trigger BUG_ON() later when the CPU comes back on. Hillf, can you please redo the patch description? I can't tell what the patch is about from the description at all. If it's a bug fix, describe the bug and maybe accompany with oops trace if possible, and then describe how it's fixed. Thanks. -- tejun