From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758037Ab1KVU3u (ORCPT ); Tue, 22 Nov 2011 15:29:50 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:52319 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756869Ab1KVU3t (ORCPT ); Tue, 22 Nov 2011 15:29:49 -0500 From: "Rafael J. Wysocki" To: "Srivatsa S. Bhat" Subject: Re: [PATCH] PM / Hibernation: Fix *massive* memory leak at early exits in hibernation Date: Tue, 22 Nov 2011 21:32:35 +0100 User-Agent: KMail/1.13.6 (Linux/3.1.0-rc10+; KDE/4.6.0; x86_64; ; ) Cc: Pavel Machek , len.brown@intel.com, tj@kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org References: <20111121173939.9486.38357.stgit@srivatsabhat.in.ibm.com> <20111122114549.GC32023@elf.ucw.cz> <4ECBF271.3040308@linux.vnet.ibm.com> In-Reply-To: <4ECBF271.3040308@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201111222132.35984.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, November 22, 2011, Srivatsa S. Bhat wrote: > On 11/22/2011 05:15 PM, Pavel Machek wrote: > > On Mon 2011-11-21 23:25:39, Rafael J. Wysocki wrote: > >> On Monday, November 21, 2011, Srivatsa S. Bhat wrote: > >>> At some of the early exit points during hibernation (exiting either due > >>> to failure or after a successful hibernation test, the memory pre-allocated > >>> for hibernation is not freed up. And this is *very* serious, because, during > >>> pre-allocation, it could have allocated upto a few *gigabytes* of memory! > >>> And hence, if a hibernation fails or even if we run some hibernation tests > >>> using the 'pm_test' framework, the system is rendered unstable due to memory > >>> becoming signifantly lower. Fix this bug. > >> > >> While the observation is valid, I'd prefer to do something like the patch > >> below. > > > > The code slowly becomes goto maze :-(. > > > > I agree.. It is already quite a mess. > > >> @@ -357,12 +357,14 @@ int hibernation_snapshot(int platform_mo > >> * successful freezer test. > >> */ > >> freezer_test_done = true; > >> - goto Close; > >> + goto Cleanup; > >> } > >> > >> error = dpm_prepare(PMSG_FREEZE); > >> - if (error) > >> - goto Complete_devices; > >> + if (error) { > >> + dpm_complete(msg); > >> + goto Cleanup; > >> + } > > > > Perhaps dpm_prepare should be changed to clean after itself in the > > error case? That is the normal convention AFAICT.... > > > > If the intention here is to merely clean up hibernation_snapshot() code, > I would not prefer to change the behaviour of dpm_prepare(), considering > things like, what parameter should we pass to dpm_complete(); is the > resultant behaviour change in dpm_suspend_start() correct or not; what > happens to all the code that uses the nice pair: dpm_suspend_start() and > dpm_resume_end() and so on. > > Perhaps there are bigger issues involved there, since I observed on a brief > look that the current code doesn't seem to strictly follow the above > convention that whoever called dpm_prepare() should call dpm_complete() > upon failure. Or may be its doing the right thing.. I don't know. > > But anyway, the good news is, even without changing dpm_prepare()'s > behaviour, we can clean up quite a bit of code in hibernation_snapshot(), > as it is. > > The first patch below does the cleanup, the second patch fixes the memory > leak and applies on top of the first patch. Wait, wait. These changes can be made in the 3.3 merge window, while I'd like the fix the bug _now_. Does anyone have any _technical_ problem with my patch posted previously in this thread? Rafael