lockdep: handle chains involving classes defined in modules

Solve this by marking the classes as unused and not printing information
about the unused classes.

Reported-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Acked-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 0 deletions

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 410c3365ad8f..ab933fecd2a1 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -3176,6 +3176,7 @@ static void zap_class(struct lock_class *class)
         list_del_rcu(&class->hash_entry);
         list_del_rcu(&class->lock_entry);
 
+        class->key = NULL;
 }
 
 static inline int within(const void *addr, void *start, unsigned long size)