From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755433AbcK3TWw (ORCPT ); Wed, 30 Nov 2016 14:22:52 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:43910 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754505AbcK3TWC (ORCPT ); Wed, 30 Nov 2016 14:22:02 -0500 Date: Wed, 30 Nov 2016 11:21:59 -0800 From: Guenter Roeck To: "Paul E. McKenney" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , sparclinux@vger.kernel.org, davem@davemloft.net Subject: Re: next: Commit 'mm: Prevent __alloc_pages_nodemask() RCU CPU stall ...' causing hang on sparc32 qemu Message-ID: <20161130192159.GB22216@roeck-us.net> References: <20161129212308.GA12447@roeck-us.net> <20161130012817.GH3924@linux.vnet.ibm.com> <20161130070212.GM3924@linux.vnet.ibm.com> <929f6b29-461a-6e94-fcfd-710c3da789e9@roeck-us.net> <20161130120333.GQ3924@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161130120333.GQ3924@linux.vnet.ibm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 30, 2016 at 04:03:33AM -0800, Paul E. McKenney wrote: > On Wed, Nov 30, 2016 at 02:52:11AM -0800, Guenter Roeck wrote: > > On 11/29/2016 11:02 PM, Paul E. McKenney wrote: > > >On Tue, Nov 29, 2016 at 08:32:51PM -0800, Guenter Roeck wrote: > > >>On 11/29/2016 05:28 PM, Paul E. McKenney wrote: > > >>>On Tue, Nov 29, 2016 at 01:23:08PM -0800, Guenter Roeck wrote: > > >>>>Hi Paul, > > >>>> > > >>>>most of my qemu tests for sparc32 targets started to fail in next-20161129. > > >>>>The problem is only seen in SMP builds; non-SMP builds are fine. > > >>>>Bisect points to commit 2d66cccd73436 ("mm: Prevent __alloc_pages_nodemask() > > >>>>RCU CPU stall warnings"); reverting that commit fixes the problem. > > And I have dropped this patch. Michal Hocko showed me the error of > my ways with this patch. > :-) On another note, I still get RCU tracebacks in the s390 tests. BUG: sleeping function called from invalid context at mm/page_alloc.c:3775 That is caused by 'rcu: Maintain special bits at bottom of ->dynticks counter'; if I recall correctly we had discussed that earlier. Thanks, Guenter