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=-2.4 required=3.0 tests=DKIM_SIGNED, MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID,USER_AGENT_MUTT 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 4D2F5C6778A for ; Tue, 3 Jul 2018 20:12:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 038F32456B for ; Tue, 3 Jul 2018 20:12:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="u7jRWvB7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 038F32456B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1752874AbeGCUMK (ORCPT ); Tue, 3 Jul 2018 16:12:10 -0400 Received: from mail-yb0-f194.google.com ([209.85.213.194]:38207 "EHLO mail-yb0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752381AbeGCUMI (ORCPT ); Tue, 3 Jul 2018 16:12:08 -0400 Received: by mail-yb0-f194.google.com with SMTP id i9-v6so1219513ybo.5 for ; Tue, 03 Jul 2018 13:12:08 -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:user-agent; bh=P7udbj33I/RjDYlty0aqbXLzXs5JGlDd9JyrBjCM7DY=; b=u7jRWvB7S8HzRNWgfrwku2W7hFAd/z3f1DT/ZJKi1jqz/rhsakwDKIpKaEopR5o1Zn 15aQF0LCwaXH9+KCor+pADCm/wAfoEMRSAtGSNeK1MgeedaNdqhw46WbEYyNFfuB9EbK p0rQ+Ppz65njVdiYkaoKT7gWJSknfXXL1AcmAjvzZCWxN1KOomnSvVKfhvpj6g42/0Ud Kn7oLsYu7N3adlC1odEyUE4Y1Gs6M6naBD//kRIstY5Vy8mLbnqCbUxbSdJ4N+oS+5Mp XyDHBM9PKQL5Jf8H3Db6ND0DG9LxAeBm53am1LudMl3qeQv+rOpWIavf6F6PiyPA2MXt BsJg== 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:user-agent; bh=P7udbj33I/RjDYlty0aqbXLzXs5JGlDd9JyrBjCM7DY=; b=Lr2L4Nf5v1ByJJkI7/ykJwVxgtn9PgABo1X3qutXtObKj8srXV6g7J0Og9Wub69FqV k1j2TrFqPVqcl0Zr4o37axnNGwpF474gnJhsd5mEkHlfokDfHOUexYSV7550u7ENRC6c q2IIhsSqw+4zn/Ce1vFZnO3BpyTtu+wqAFpZHnoIOK32JmFqkVHpof1AZiAqxAY5KisV UeYjqNBXb/NnLVglGJBGC++oD9XxbPxXaeDs5Fltao6Lbq8baCV8gcF3+nRTf18I7TqM ziBEHTICR68pwk89mEkTOLTH2GmMoGlqXW7V0C1ht6aKDMQ5BSI+M5LyrAM/feqDJh2d aWkA== X-Gm-Message-State: APt69E1cLPkvTJMwWIGO4MYhixhZlcg+mKzViOkl2tYWAfHqqQ0tWahk mcUn1beMDT2Ywfl7N93vb+g= X-Google-Smtp-Source: AAOMgpdYryzvOtl6wEhNxeSKkFuhRH37YYn9+nmMlgTyFNLvQskCiQu/RzYyR8670zNYRSlU4KIbSg== X-Received: by 2002:a25:283:: with SMTP id 125-v6mr7175655ybc.473.1530648727973; Tue, 03 Jul 2018 13:12:07 -0700 (PDT) Received: from localhost ([2620:10d:c091:200::3:a4be]) by smtp.gmail.com with ESMTPSA id d11-v6sm665370ywd.1.2018.07.03.13.12.07 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Jul 2018 13:12:07 -0700 (PDT) Date: Tue, 3 Jul 2018 13:12:05 -0700 From: Tejun Heo To: "Paul E. McKenney" Cc: jiangshanlai@gmail.com, linux-kernel@vger.kernel.org Subject: Re: WARN_ON_ONCE() in process_one_work()? Message-ID: <20180703201205.GA72677@devbig577.frc2.facebook.com> References: <20180620192901.GA9956@linux.vnet.ibm.com> <20180702210540.GL533219@devbig577.frc2.facebook.com> <20180703040518.GV3593@linux.vnet.ibm.com> <20180703164044.GA400@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180703164044.GA400@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Paul. On Tue, Jul 03, 2018 at 09:40:44AM -0700, Paul E. McKenney wrote: > > I will apply this, but be advised that I have not seen that WARN_ON_ONCE() > > trigger since. :-/ > > But I get a build error: > > kernel/workqueue.o: In function `worker_attach_to_pool': > workqueue.c:(.text+0x63c): undefined reference to `cpuhp_target_state' > workqueue.c:(.text+0x647): undefined reference to `cpuhp_current_state' > /home/paulmck/public_git/linux-rcu/Makefile:1015: recipe for target 'vmlinux' failed > > My guess is that the worker_attach_to_pool() code needs to change so > as to invoke cpuhp_current_state() and cpuhp_target_state() only in > CONFIG_HOTPLUG_CPU=y kernels, but I figured I should defer to you. Just to clarify, the bug happened on a kernel with cpuhp enabled, right? Thanks. -- tejun