Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755617Ab3EFTBZ (ORCPT ); Mon, 6 May 2013 15:01:25 -0400 Received: from mail-ye0-f178.google.com ([209.85.213.178]:44019 "EHLO mail-ye0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754882Ab3EFTBW (ORCPT ); Mon, 6 May 2013 15:01:22 -0400 X-Greylist: delayed 363 seconds by postgrey-1.27 at vger.kernel.org; Mon, 06 May 2013 15:01:22 EDT Date: Mon, 6 May 2013 12:01:15 -0700 From: Tejun Heo To: Colin Cross Cc: linux-kernel@vger.kernel.org, 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@vger.kernel.org, linux-pm@vger.kernel.org, netdev@vger.kernel.org, Linus Torvalds , Ben Chan Subject: Re: [PATCH 2/2] lockdep: check that no locks held at freeze time Message-ID: <20130506190115.GB800@mtj.dyndns.org> References: <1367615050-3894-1-git-send-email-ccross@android.com> <1367615050-3894-2-git-send-email-ccross@android.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1367615050-3894-2-git-send-email-ccross@android.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1339 Lines: 31 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). Thanks. -- tejun -- 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/