Re: net-next: NULL pointer dereference on adding a net namespace and a system freeze

[Steffen Klassert <steffen.klassert@secunet.com>]

On Tue, Mar 11, 2014 at 05:40:26AM -0700, Eric Dumazet wrote:
> On Tue, 2014-03-11 at 13:00 +0100, Steffen Klassert wrote:
> 
> > I was unable to reproduce this here, but it looks like the flowcache
> > namespace changes are still not complete. We leak an active timer
> > and all the allocated resources when we exit a namespace.
> > 
> > Could you please try the patch below?
> > 
> > Also, please send your config if the patch does not fix your problem.
> > 
> > Thanks!
> > 
> > ---
> >  include/net/flow.h     |    1 +
> >  net/core/flow.c        |   18 ++++++++++++++++++
> >  net/xfrm/xfrm_policy.c |    7 ++++++-
> >  3 files changed, 25 insertions(+), 1 deletion(-)
> > 
> > diff --git a/include/net/flow.h b/include/net/flow.h
> > index bee3741..64fd248 100644
> > --- a/include/net/flow.h
> > +++ b/include/net/flow.h
> > @@ -219,6 +219,7 @@ struct flow_cache_object *flow_cache_lookup(struct net *net,
> >  					    u8 dir, flow_resolve_t resolver,
> >  					    void *ctx);
> >  int flow_cache_init(struct net *net);
> > +void flow_cache_fini(struct net *net);
> >  
> >  void flow_cache_flush(struct net *net);
> >  void flow_cache_flush_deferred(struct net *net);
> > diff --git a/net/core/flow.c b/net/core/flow.c
> > index 102f8ea..d31c3c4 100644
> > --- a/net/core/flow.c
> > +++ b/net/core/flow.c
> > @@ -484,3 +484,21 @@ err:
> >  	return -ENOMEM;
> >  }
> >  EXPORT_SYMBOL(flow_cache_init);
> > +
> > +void flow_cache_fini(struct net *net)
> > +{
> > +	int i;
> > +	struct flow_cache *fc = &net->xfrm.flow_cache_global;
> > +
> > +	del_timer(&fc->rnd_timer);
> 
> 
> del_timer_sync() I guess is better.
> 

Right.

I've just noticed that I also forgot to do a
unregister_hotcpu_notifier(&fc->hotcpu_notifier).

Will update the next version according to that.