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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>