locking/lockdep: Don't complain about incorrect name for no validate class

It is possible to ignore the validation for a certain lock by using:

	lockdep_set_novalidate_class()

on it. Each invocation will assign a new name to the class it created
for created __lockdep_no_validate__. That means that once
lockdep_set_novalidate_class() has been used on two locks then
class->name won't match lock->name for the first lock triggering the
warning.

So ignore changed non-matching ->name pointer for the special
__lockdep_no_validate__ class.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/20190517212234.32611-1-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index c47788fa85f9491069ca607613d808ed0049523c..6b283b4f87aa541a2b8dafcd87c662dfabc4a60c 100644 (file)
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -732,7 +732,8 @@ look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass)
                         * Huh! same key, different name? Did someone trample
                         * on some memory? We're most confused.
                         */
-                       WARN_ON_ONCE(class->name != lock->name);
+                       WARN_ON_ONCE(class->name != lock->name &&
+                                    lock->key != &__lockdep_no_validate__);
                        return class;
                }
        }