Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <55111c45-0f8f-c6f9-640c-6919939b77dd@I-love.SAKURA.ne.jp>
Date:   Mon, 19 Sep 2022 00:01:30 +0900
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.2.2
Content-Language: en-US
To:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
        Waiman Long <longman@redhat.com>,
        Boqun Feng <boqun.feng@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>
From:   Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Subject: [PATCH] lockdep: report name and key when look_up_lock_class() got
 confused
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

Printing this information will be helpful.

  ------------[ cut here ]------------
  class->name=slock-AF_INET6 lock->name=l2tp_sock lock->key=l2tp_socket_class
  WARNING: CPU: 2 PID: 9237 at kernel/locking/lockdep.c:940 look_up_lock_class+0xcc/0x140
  Modules linked in:
  CPU: 2 PID: 9237 Comm: a.out Not tainted 6.0.0-rc5-00094-ga335366bad13-dirty #860
  Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
  RIP: 0010:look_up_lock_class+0xcc/0x140

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 kernel/locking/lockdep.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 64a13eb56078..a22469dbeeee 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -934,8 +934,10 @@ 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 &&
-				     lock->key != &__lockdep_no_validate__);
+			WARN_ONCE(class->name != lock->name &&
+				  lock->key != &__lockdep_no_validate__,
+				  "class->name=%s lock->name=%s lock->key=%ps\n",
+				  class->name, lock->name, lock->key);
 			return class;
 		}
 	}
-- 
2.34.1