Messages in this thread | | | Date | Thu, 19 Jun 2014 22:37:17 +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 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?
If that's impossible due to other memory allocator constraints, then instead of inventing a whole new API we can simply flag the relevent data in the memory allocator as we do with the debug objects mem cache itself (SLAB_DEBUG_OBJECTS).
Thanks,
tglx
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