From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x22b.google.com (mail-wm0-x22b.google.com [IPv6:2a00:1450:400c:c09::22b]) (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 3vC2jH241nzDq5k for ; Tue, 31 Jan 2017 08:34:39 +1100 (AEDT) Received: by mail-wm0-x22b.google.com with SMTP id b65so52054855wmf.0 for ; Mon, 30 Jan 2017 13:34:39 -0800 (PST) Date: Mon, 30 Jan 2017 21:34:35 +0000 From: Matt Fleming To: Michael Ellerman Cc: fweisbec@gmail.com, tglx@linutronix.de, pmladek@suse.com, hpa@zytor.com, efault@gmx.de, sergey.senozhatsky.work@gmail.com, peterz@infradead.org, mgorman@techsingularity.net, wanpeng.li@hotmail.com, umgwanakikbuti@gmail.com, byungchul.park@lge.com, jack@suse.cz, mingo@kernel.org, riel@redhat.com, luca.abeni@unitn.it, yuyang.du@intel.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org, "linuxppc-dev@lists.ozlabs.org" , "linux-next@vger.kernel.org" Subject: Re: [tip:sched/core] sched/core: Add debugging code to catch missing update_rq_clock() calls Message-ID: <20170130213435.GM31613@codeblueprint.co.uk> References: <20160921133813.31976-8-matt@codeblueprint.co.uk> <87tw8gutp6.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <87tw8gutp6.fsf@concordia.ellerman.id.au> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 31 Jan, at 08:24:53AM, Michael Ellerman wrote: > > I'm hitting this on multiple powerpc systems: > > [ 38.339126] rq->clock_update_flags < RQCF_ACT_SKIP > [ 38.339134] ------------[ cut here ]------------ > [ 38.339142] WARNING: CPU: 2 PID: 1 at kernel/sched/sched.h:804 detach_task_cfs_rq+0xa0c/0xd10 [...] > I assume I should be worried? Thanks for the report. No need to worry, the bug has existed for a while, this patch just turns on the warning ;-) The following commit queued up in tip/sched/core should fix your issues (assuming you see the same callstack on all your powerpc machines): https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?h=sched/core&id=1b1d62254df0fe42a711eb71948f915918987790