On Thu, Jun 19, 2014 at 03:19:39PM -0500, 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? Good point. The patch I just sent will complain at callback-invocation time because the debug-object information won't be present. One way to handle this would be for rcu_do_batch() to avoid complaining if it gets a callback that has not been through call_rcu()'s debug_rcu_head_queue(). One way to do that would be to have an alternative to debug_object_deactivate() that does not complain if it is handed an unactivated object. Another way to handle this would be for me to put the definition of debug_rcu_head_queue() somewhere where the sl*b allocator could get at it, and have the sl*b allocators invoke it some at initialization and within the RCU callback. Other thoughts? Thanx, Paul -- 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>