Date: Tue, 5 Mar 2013 18:11:10 -0500
From: "J. Bruce Fields" <bfields@fieldses.org>
To: Tejun Heo <tj@kernel.org>
Cc: Jeff Layton <jlayton@redhat.com>,
        "Myklebust, Trond" <Trond.Myklebust@netapp.com>,
        Oleg Nesterov <oleg@redhat.com>,
        Mandeep Singh Baines <msb@chromium.org>,
        Ming Lei <ming.lei@canonical.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        "Rafael J. Wysocki" <rjw@sisk.pl>,
        Andrew Morton <akpm@linux-foundation.org>,
        Ingo Molnar <mingo@redhat.com>
Subject: Re: LOCKDEP: 3.9-rc1: mount.nfs/4272 still has locks held!
Message-ID: <20130305231110.GK15816@fieldses.org>
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On Tue, Mar 05, 2013 at 09:49:54AM -0800, Tejun Heo wrote:
> On Tue, Mar 05, 2013 at 09:46:48AM -0800, Tejun Heo wrote:
> > So, I think this is why implementing freezer as a separate blocking
> > mechanism isn't such a good idea.  We're effectively introducing a
> > completely new waiting state to a lot of unsuspecting paths which
> > generates a lot of risks and eventually extra complexity to work
> > around those.  I think we really should update freezer to re-use the
> > blocking points we already have - the ones used for signal delivery
> > and ptracing.  That way, other code paths don't have to worry about an
> > extra stop state and we can confine most complexities to freezer
> > proper.
> 
> Also, consolidating those wait states means that we can solve the
> event-to-response latency problem for all three cases - signal, ptrace
> and freezer, rather than adding separate backing-out strategy for
> freezer.

Meanwhile, as none of this sounds likely to be done this time
around--are we backing out the new lockdep warnings?

--b.