From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752447Ab3BTXYt (ORCPT ); Wed, 20 Feb 2013 18:24:49 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:41698 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752375Ab3BTXYr (ORCPT ); Wed, 20 Feb 2013 18:24:47 -0500 Date: Wed, 20 Feb 2013 15:24:46 -0800 From: Andrew Morton To: Mandeep Singh Baines Cc: linux-kernel@vger.kernel.org, Oleg Nesterov , Tejun Heo , "Rafael J. Wysocki" Subject: Re: [PATCH v4] lockdep: check that no locks held at freeze time Message-Id: <20130220152446.a65ff84f.akpm@linux-foundation.org> In-Reply-To: <1361402236-28644-1-git-send-email-msb@chromium.org> References: <20130220223013.GA15760@redhat.com> <1361402236-28644-1-git-send-email-msb@chromium.org> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; 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 Wed, 20 Feb 2013 15:17:16 -0800 Mandeep Singh Baines wrote: > We shouldn't try_to_freeze if locks are held. > > ... > > @@ -43,6 +44,9 @@ extern void thaw_kernel_threads(void); > > + if (!(current->flags & PF_NOFREEZE)) > + debug_check_no_locks_held(current, > + > "lock held while trying to freeze"); > ... > > + debug_check_no_locks_held(tsk, "lock held at task exit time"); There doesn't seem much point in adding the `msg' to debug_check_no_locks_held() - the dump_stack() in print_held_locks_bug() will tell us the same thing. Maybe just change the print_held_locks_bug() messages so they stop assuming they were called from do_exit()? Also, I wonder if the `tsk' arg is needed. In both callers tsk==current. Is it likely that we'll ever call debug_check_no_locks_held() for any task other than `current'?