Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755583Ab3EFTaW (ORCPT ); Mon, 6 May 2013 15:30:22 -0400 Received: from mail-ve0-f181.google.com ([209.85.128.181]:46030 "EHLO mail-ve0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754882Ab3EFTaU (ORCPT ); Mon, 6 May 2013 15:30:20 -0400 MIME-Version: 1.0 In-Reply-To: <20130506190115.GB800@mtj.dyndns.org> References: <1367615050-3894-1-git-send-email-ccross@android.com> <1367615050-3894-2-git-send-email-ccross@android.com> <20130506190115.GB800@mtj.dyndns.org> Date: Mon, 6 May 2013 12:30:19 -0700 X-Google-Sender-Auth: wkfC4fOc8q0WCqZCQTIixu44dB0 Message-ID: Subject: Re: [PATCH 2/2] lockdep: check that no locks held at freeze time From: Colin Cross To: Tejun Heo Cc: lkml , Trond Myklebust , Len Brown , Pavel Machek , "Rafael J. Wysocki" , Peter Zijlstra , Ingo Molnar , "J. Bruce Fields" , "David S. Miller" , Andrew Morton , Mandeep Singh Baines , Paul Walmsley , Al Viro , "Eric W. Biederman" , Oleg Nesterov , linux-nfs , Linux PM list , netdev , Linus Torvalds , Ben Chan Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1636 Lines: 32 On Mon, May 6, 2013 at 12:01 PM, Tejun Heo wrote: > On Fri, May 03, 2013 at 02:04:10PM -0700, Colin Cross wrote: >> From: Mandeep Singh Baines >> >> We shouldn't try_to_freeze if locks are held. Holding a lock can cause a >> deadlock if the lock is later acquired in the suspend or hibernate path >> (e.g. by dpm). Holding a lock can also cause a deadlock in the case of >> cgroup_freezer if a lock is held inside a frozen cgroup that is later >> acquired by a process outside that group. >> >> History: >> This patch was originally applied as 6aa9707099c and reverted in >> dbf520a9d7d4 because NFS was freezing with locks held. It was >> deemed better to keep the bad freeze point in NFS to allow laptops >> to suspend consistently. The previous patch in this series converts >> NFS to call _unsafe versions of the freezable helpers so that >> lockdep doesn't complain about them until a more correct fix >> can be applied. > > I don't care about %current change, especially given that it's a debug > interface but that really should be a separate patch, so please split > it out if you want it (and I think we want it). The current change was requested by akpm and was part of the original patch. Is it really worth confusing the history of this patch even more, applying it the first time, reverting it, and then applying it again in two parts? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/