Re: [PATCH 0/4] allow freezing of tasks with netfs calls in flight

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Tuesday, October 11, 2011, Jeff Layton wrote:
> On Tue, 11 Oct 2011 08:18:19 +0200
> Pavel Machek <pavel@ucw.cz> wrote:
> 
> > Hi!
> > 
> > > We've had a number of reports recently of people with NFS and CIFS
> > > mounts that were unable to suspend or hibernate their machines. Here
> > > are a couple of Fedora bugs that illustrate the problem:
> > > 
> > >     https://bugzilla.redhat.com/show_bug.cgi?id=712088
> > >     https://bugzilla.redhat.com/show_bug.cgi?id=717735
> > > 
> > > When it occurs the problem is pretty clear. We have a task that's
> > > sleeping in the kernel in TASK_KILLABLE sleep, generally waiting
> > > for a reply to come in. Often though, userspace has already taken
> > > down the interface so that reply will never come. The process then
> > > fails to freeze and the suspend fails.
> > 
> > Userspace should not take interface down for suspend (*). Why do that?
> > 
> 
> I suspect that NetworkManager does this to try and allow for the case
> where someone suspends their laptop and then wanders off to another
> network and then resumes.

That's correct.

> Either way, we still want to allow suspend and hibernate to work regardless
> of what userspace does during the process.

Very true. :-)

Thanks,
Rafael