Re: slub/debugobjects: lockup when freeing memory

From: Thomas Gleixner
Date: Thu Jun 19 2014 - 16:28:32 EST


On Thu, 19 Jun 2014, Christoph Lameter wrote:
> On Thu, 19 Jun 2014, Thomas Gleixner wrote:
>
> > Well, no. Look at the callchain:
> >
> > __call_rcu
> > debug_object_activate
> > rcuhead_fixup_activate
> > debug_object_init
> > kmem_cache_alloc
> >
> > So call rcu activates the object, but the object has no reference in
> > the debug objects code so the fixup code is called which inits the
> > object and allocates a reference ....
>
> So we need to init the object in the page struct before the __call_rcu?

Looks like RCU is lazily relying on the state callback to initialize
the objects.

There is an unused debug_init_rcu_head() inline in kernel/rcu/update.c

Paul????


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