For the special novalidate class (lockdep_set_novalidate_class), multiple
locks with different names may use the same class. The WARN_ON_ONCE()
check in look_up_lock_class() will then report an unnecessary warning.
The current users of lockdep_set_novalidate_class() includes the
device mutex, one mutex and one rwsem in drivers/md/bcache/btree.c.
So the novalidate class is now excluded from the check.
Signed-off-by: Waiman Long <long...@redhat.com>
---
kernel/locking/lockdep.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index dd13f865ad40..10babc35953b 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -693,9 +693,12 @@ look_up_lock_class(const struct lockdep_map *lock,
unsigned int subclass)
if (class->key == key) {
/*
* Huh! same key, different name? Did someone trample
- * on some memory? We're most confused.
+ * on some memory? We're most confused unless it is
+ * __lockdep_no_validate__ where different locks can
+ * use the same class.
*/
- WARN_ON_ONCE(class->name != lock->name);
+ WARN_ON_ONCE((key != __lockdep_no_validate__.subkeys) &&
+ (class->name != lock->name));
return class;
}
}
--
2.18.0
