From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755313AbdETOZz (ORCPT ); Sat, 20 May 2017 10:25:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:33130 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751528AbdETOZy (ORCPT ); Sat, 20 May 2017 10:25:54 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4D20E23990 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Sat, 20 May 2017 10:25:50 -0400 From: Steven Rostedt To: Christoph Hellwig Cc: Thomas Gleixner , LKML , linux-mm@kvack.org, Johannes Weiner , Michal Hocko , Christoph Lameter , Andrew Morton , Peter Zijlstra Subject: Re: [PATCH] slub/memcg: Cure the brainless abuse of sysfs attributes Message-ID: <20170520102550.2f793194@gandalf.local.home> In-Reply-To: <20170520131645.GA5058@infradead.org> References: <20170520131645.GA5058@infradead.org> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 20 May 2017 06:16:45 -0700 Christoph Hellwig wrote: > On Sat, May 20, 2017 at 12:52:03PM +0200, Thomas Gleixner wrote: > > This should be rewritten proper by adding a propagate() callback to those > > slub_attributes which must be propagated and avoid that insane conversion > > to and from ASCII > > Exactly.. > > >, but that's too large for a hot fix. > > What made this such a hot fix? Looks like this crap has been in > for quite a while. It can cause a deadlock with get_online_cpus() that has been uncovered by recent cpu hotplug and lockdep changes that Thomas and Peter have been doing. [ 102.567308] Possible unsafe locking scenario: [ 102.567308] [ 102.574846] CPU0 CPU1 [ 102.580148] ---- ---- [ 102.585421] lock(cpu_hotplug.lock); [ 102.589808] lock(slab_mutex); [ 102.596166] lock(cpu_hotplug.lock); [ 102.603028] lock(slab_mutex); [ 102.606846] [ 102.606846] *** DEADLOCK *** -- Steve From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 10C44280753 for ; Sat, 20 May 2017 10:25:55 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id c6so77299479pfj.5 for ; Sat, 20 May 2017 07:25:55 -0700 (PDT) Received: from mail.kernel.org (mail.kernel.org. [198.145.29.99]) by mx.google.com with ESMTPS id c188si11554954pfb.309.2017.05.20.07.25.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 20 May 2017 07:25:54 -0700 (PDT) Date: Sat, 20 May 2017 10:25:50 -0400 From: Steven Rostedt Subject: Re: [PATCH] slub/memcg: Cure the brainless abuse of sysfs attributes Message-ID: <20170520102550.2f793194@gandalf.local.home> In-Reply-To: <20170520131645.GA5058@infradead.org> References: <20170520131645.GA5058@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Hellwig Cc: Thomas Gleixner , LKML , linux-mm@kvack.org, Johannes Weiner , Michal Hocko , Christoph Lameter , Andrew Morton , Peter Zijlstra On Sat, 20 May 2017 06:16:45 -0700 Christoph Hellwig wrote: > On Sat, May 20, 2017 at 12:52:03PM +0200, Thomas Gleixner wrote: > > This should be rewritten proper by adding a propagate() callback to those > > slub_attributes which must be propagated and avoid that insane conversion > > to and from ASCII > > Exactly.. > > >, but that's too large for a hot fix. > > What made this such a hot fix? Looks like this crap has been in > for quite a while. It can cause a deadlock with get_online_cpus() that has been uncovered by recent cpu hotplug and lockdep changes that Thomas and Peter have been doing. [ 102.567308] Possible unsafe locking scenario: [ 102.567308] [ 102.574846] CPU0 CPU1 [ 102.580148] ---- ---- [ 102.585421] lock(cpu_hotplug.lock); [ 102.589808] lock(slab_mutex); [ 102.596166] lock(cpu_hotplug.lock); [ 102.603028] lock(slab_mutex); [ 102.606846] [ 102.606846] *** DEADLOCK *** -- Steve -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org