Messages in this thread | | | Date | Thu, 19 Jun 2014 23:32:41 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: slub/debugobjects: lockup when freeing memory |
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On Thu, 19 Jun 2014, Paul E. McKenney wrote:
> On Thu, Jun 19, 2014 at 10:37:17PM +0200, Thomas Gleixner wrote: > > On Thu, 19 Jun 2014, Paul E. McKenney wrote: > > > On Thu, Jun 19, 2014 at 09:29:08PM +0200, Thomas Gleixner wrote: > > > > On Thu, 19 Jun 2014, Paul E. McKenney 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 .... > > > > > > OK, got it. And you are right, call_rcu() has done this for a very > > > long time, so not sure what changed. But it seems like the right > > > approach is to provide a debug-object-free call_rcu_alloc() for use > > > by the memory allocators. > > > > > > Seem reasonable? If so, please see the following patch. > > > > Not really, you're torpedoing the whole purpose of debugobjects :) > > > > So, why can't we just init the rcu head when the stuff is created? > > That would allow me to keep my code unchanged, so I am in favor. ;-)
Almost unchanged. You need to provide a function to do so, i.e. make use of
debug_init_rcu_head()
Thanks,
tglx
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