diff --git a/[refs] b/[refs]
index 62c094d1a9a3..248682821b06 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3295f0ef9ff048a4619ede597ad9ec9cab725654
+refs/heads/master: b42e737e576339c795d9ac77a1fce6057f6bc0cf
diff --git a/trunk/include/linux/lockdep.h b/trunk/include/linux/lockdep.h
index 67f42b300c65..c88aa3d8e87f 100644
--- a/trunk/include/linux/lockdep.h
+++ b/trunk/include/linux/lockdep.h
@@ -191,7 +191,12 @@ struct lock_chain {
 };
 
 #define MAX_LOCKDEP_KEYS_BITS		11
-#define MAX_LOCKDEP_KEYS		(1UL << MAX_LOCKDEP_KEYS_BITS)
+/*
+ * Subtract one because we offset hlock->class_idx by 1 in order
+ * to make 0 mean no class. This avoids overflowing the class_idx
+ * bitfield and hitting the BUG in hlock_class().
+ */
+#define MAX_LOCKDEP_KEYS		((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
 
 struct held_lock {
 	/*