[PATCH] locking/lockdep: Don't complain about wrong name for no validate class

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
	tglx@linutronix.de,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH] locking/lockdep: Don't complain about wrong name for no validate class
Date: Fri, 17 May 2019 23:22:34 +0200	[thread overview]
Message-ID: <20190517212234.32611-1-bigeasy@linutronix.de> (raw)

It is possible to ignore the validation for a certain log be 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.

Ignoring changed non-matching ->name pointer for the
__lockdep_no_validate__ class.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 kernel/locking/lockdep.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index d06190fa50822..38be69d344f7f 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -731,7 +731,8 @@ 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;
 		}
 	}
-- 
2.20.1

