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>

1 files changed, 5 insertions, 0 deletions

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 981cd485428..a288ae107b5 100644
--- a/kernel/lockdep.c
+++ b/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 @@ cache_hit:
 
                 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;
         }