From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: Random freezing failure with NFS and automount Date: Tue, 5 Jul 2011 01:29:01 +0200 Message-ID: <201107050129.01936.rjw@sisk.pl> References: <20110628155054.GA23242@dirshya.in.ibm.com> <201107030907.18203.rjw@sisk.pl> <20110704171449.GC5357@dirshya.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110704171449.GC5357@dirshya.in.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: svaidy@linux.vnet.ibm.com Cc: linux-pm@lists.linux-foundation.org List-Id: linux-pm@vger.kernel.org On Monday, July 04, 2011, Vaidyanathan Srinivasan wrote: > * Rafael J. Wysocki [2011-07-03 09:07:18]: > > > Hi, > > > > On Tuesday, June 28, 2011, Vaidyanathan Srinivasan wrote: > > > Hi, > > > > > > I have random freezing failures on my laptop running 2.6.39 kernel. > > > The laptop has NFS client and automount. Network could have been > > > disconnected by the time suspend is attempted, hence nfs client should > > > fail all operations, just freeze and allow laptop to suspend. > > > > > > I need some help to drill deeper at this log and also suggestions on > > > config options to try and get more information to help me root cause > > > this issue. > > > > > > This happens once in 4-5 suspend/resume cycles, does not succeed on > > > retry, eventually I have to reboot. > > > > This is a tasks freezer failure, ie. the freezing of tasks fails, because > > one of them refuses to handle signals for 20 s. This is probably related > > to waiting on a VFS mutex in the TASK_UNINTERRUPTIBLE state. > > > > We don't handle those cases nicely right now, sorry about that. > > Hi Rafael, > > Thanks for taking a look. The NFS mount option in hard,intr so > I would expect an interruptible sleep. I will take this to file > system folks and see if they can help. I will also review my mount > options to improve the situation. > > When you said we are not handling the situation, what did you mean? I meant that the freezing fails in those cases. > We seem to cleanly unfreeze the tasks and return the system to working > state (though suspend fails). Maybe we should send some signals and > try to prod the failing task to get to freeze? What is needed here to > improve our framework? Probably there is a bug (or more bugs) in our error code paths. That wouldn't suprpise me too much, because those code paths are not tested very hard ... Thanks, Rafael