From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x242.google.com (mail-oi0-x242.google.com [IPv6:2607:f8b0:4003:c06::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3st0vm5dJdzDrbq for ; Tue, 11 Oct 2016 00:14:28 +1100 (AEDT) Received: by mail-oi0-x242.google.com with SMTP id e12so1256666oib.3 for ; Mon, 10 Oct 2016 06:14:28 -0700 (PDT) Sender: Tejun Heo Date: Mon, 10 Oct 2016 09:14:17 -0400 From: Tejun Heo To: Michael Ellerman Cc: torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, jiangshanlai@gmail.com, akpm@linux-foundation.org, kernel-team@fb.com, "linuxppc-dev@lists.ozlabs.org" Subject: Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot) Message-ID: <20161010131417.GC29742@mtj.duckdns.org> References: <1473967821-24363-1-git-send-email-tj@kernel.org> <1473967821-24363-2-git-send-email-tj@kernel.org> <20160917172314.GB10771@mtj.duckdns.org> <87twck5wqo.fsf@concordia.ellerman.id.au> <20161010130253.GB29742@mtj.duckdns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20161010130253.GB29742@mtj.duckdns.org> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, Oct 10, 2016 at 09:02:53AM -0400, Tejun Heo wrote: > Hello, Michael. > > On Mon, Oct 10, 2016 at 09:22:55PM +1100, Michael Ellerman wrote: > > This patch seems to be causing one of my Power8 boxes not to boot. > > > > Specifically commit 3347fa092821 ("workqueue: make workqueue available > > early during boot") in linux-next. > > > > If I revert this on top of next-20161005 then the machine boots again. > > > > I've attached the oops below. It looks like the cfs_rq of p->se is NULL? > > Hah, weird that it's arch dependent, or maybe it's just different > config options. Most likely, it's caused by workqueue_init() call > being moved too early. Can you please try the following patch and see > whether the problem goes away? And if it does, can you please post the boot log with kernel boot option "initcall_debug=1" specified? Thanks. -- tejun