[PATCH v2 1/4] locking/lockdep: Add a helper to validate the locking context without a lock

[Thomas Weißschuh]

In some cases the specific codepath and its locking operations depend on
the runtime configuration of the system. lockdep will only detect lock
misuse if the system is configured in the right way by chance.

To make lockdep more reliable in these cases, introduce a helper macro
to define a lockdep map without any corresponding lock.

This differs from the related DEFINE_WAIT_OVERRIDE_MAP() as the context
of the map is checked against the current locking context.

Link: https://lore.kernel.org/lkml/20241217142032.55793-1-acarmina@xxxxxxxxxx/
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
---
 include/linux/lockdep.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 621566345406..ae3e332f1518 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -315,6 +315,11 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
 		.wait_type_inner = _wait_type,		\
 		.lock_type = LD_LOCK_WAIT_OVERRIDE, }
 
+#define DEFINE_WAIT_ASSERT_MAP(_name, _wait_type)	\
+	struct lockdep_map _name = {			\
+		.name = #_name "-wait-type-assert",	\
+		.wait_type_inner = _wait_type, }
+
 #else /* !CONFIG_LOCKDEP */
 
 static inline void lockdep_init_task(struct task_struct *task)
@@ -407,6 +412,9 @@ extern int lockdep_is_held(const void *);
 #define DEFINE_WAIT_OVERRIDE_MAP(_name, _wait_type)	\
 	struct lockdep_map __maybe_unused _name = {}
 
+#define DEFINE_WAIT_ASSERT_MAP(_name, _wait_type)	\
+	struct lockdep_map __maybe_unused _name = {}
+
 #endif /* !LOCKDEP */
 
 #ifdef CONFIG_PROVE_LOCKING

-- 
2.53.0