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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 B89FAFD21E1 for ; Mon, 30 Jul 2018 17:16:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 759CF20857 for ; Mon, 30 Jul 2018 17:16:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 759CF20857 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731047AbeG3SwN (ORCPT ); Mon, 30 Jul 2018 14:52:13 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:57056 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726782AbeG3SwN (ORCPT ); Mon, 30 Jul 2018 14:52:13 -0400 Received: from p4fea5a5a.dip0.t-ipconnect.de ([79.234.90.90] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1fkBmD-0004Go-0Z; Mon, 30 Jul 2018 19:16:09 +0200 Date: Mon, 30 Jul 2018 19:16:08 +0200 (CEST) From: Thomas Gleixner To: Sodagudi Prasad cc: Peter Zijlstra , Sebastian Andrzej Siewior , isaacm@codeaurora.org, matt@codeblueprint.co.uk, mingo@kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, pkondeti@codeaurora.org, stable@vger.kernel.org Subject: Re: [PATCH] stop_machine: Disable preemption after queueing stopper threads In-Reply-To: <109d0e70606ccd34861a80525d6d11aa@codeaurora.org> Message-ID: References: <1531856129-9871-1-git-send-email-isaacm@codeaurora.org> <20180724062350.nlem2suuy5wlxpts@linutronix.de> <20180730112140.GH2494@hirez.programming.kicks-ass.net> <109d0e70606ccd34861a80525d6d11aa@codeaurora.org> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 30 Jul 2018, Sodagudi Prasad wrote: > How about including below change as well? Currently, there is no way to That would be a completely separate change. > identify thread migrations completed or not. When we observe this issue, the > symptom was work queue lock up. It is better to have some timeout here and > induce the bug_on. BUG_ON() is wrong. Why kill the thing if there is at least a theoretical chance that stuff can continue half baken so you can get more info out of it. The back trace is pretty much uninteresting. Thanks, tglx