lockdep: add stack dumps to asserts

Have a better idea about exactly which loc causes a lockdep
limit overflow. Often it's a bug or inefficiency in that
subsystem.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1237376327.5069.253.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/lockdep.c

@@ -792,6 +792,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 
 		printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return NULL;
 	}
 	class = lock_classes + nr_lock_classes++;
@@ -855,6 +856,7 @@ static struct lock_list *alloc_list_entry(void)
 
 		printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return NULL;
 	}
 	return list_entries + nr_list_entries++;
@@ -1681,6 +1683,7 @@ static inline int lookup_chain_cache(struct task_struct *curr,
 
 		printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return 0;
 	}
 	chain = lock_chains + nr_lock_chains++;
@@ -2540,6 +2543,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 		debug_locks_off();
 		printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return 0;
 	}
 
@@ -2636,6 +2640,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 		debug_locks_off();
 		printk("BUG: MAX_LOCK_DEPTH too low!\n");
 		printk("turning off the locking correctness validator.\n");
+		dump_stack();
 		return 0;
 	}