From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755189AbcIEIJh (ORCPT ); Mon, 5 Sep 2016 04:09:37 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:44624 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755141AbcIEIJf (ORCPT ); Mon, 5 Sep 2016 04:09:35 -0400 Date: Mon, 5 Sep 2016 10:09:33 +0200 From: Peter Zijlstra To: Felipe Balbi Cc: Alan Stern , "Paul E. McKenney" , Ingo Molnar , USB list , Kernel development list Subject: Re: Memory barrier needed with wake_up_process()? Message-ID: <20160905080933.GW10153@twins.programming.kicks-ass.net> References: <20160902191857.GL10153@twins.programming.kicks-ass.net> <20160902221658.GO10153@twins.programming.kicks-ass.net> <8737lh79mm.fsf@linux.intel.com> <20160903121915.GC2794@worktop> <8760qdks6s.fsf@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8760qdks6s.fsf@linux.intel.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 03, 2016 at 04:51:07PM +0300, Felipe Balbi wrote: > > That said, I cannot spot an obvious fail, > > okay, but a fail does exist. Any hints on what extra information I could > capture to help figuring this one out? More information on which sleep is not waking woudl help I suppose. That greatly limits the amount of code one has to stare at. Also, a better picture of all threads involved in the wakeup. Alan seems to suggest there's multiple CPUs involved in the wakeup.