[PATCH 03/17] locking/rwsem: assert static storage for semaphore definitions

[Yury Norov]

The static rwsem initializers rely on persistent lockdep class keys,
both for their own maps and for embedded locks or wait queues.

Enforce static storage in DECLARE_RWSEM(), including PREEMPT_RT, and in
__DEFINE_PERCPU_RWSEM(), covering both public per-CPU rwsem declarations.
Automatic objects must use init_rwsem() or percpu_init_rwsem().

Assisted-by: OpenAI Codex
Signed-off-by: Yury Norov <ynorov@xxxxxxxxxx>
---
 include/linux/percpu-rwsem.h | 4 +++-
 include/linux/rwsem.h        | 7 +++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index 39d5bf8e6562..680c3efc14c8 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_PERCPU_RWSEM_H
 #define _LINUX_PERCPU_RWSEM_H
 
+#include <linux/compiler.h>
 #include <linux/atomic.h>
 #include <linux/percpu.h>
 #include <linux/rcuwait.h>
@@ -36,7 +37,8 @@ is_static struct percpu_rw_semaphore name = {				\
 	.waiters = __WAIT_QUEUE_HEAD_INITIALIZER(name.waiters),		\
 	.block = ATOMIC_INIT(0),					\
 	__PERCPU_RWSEM_DEP_MAP_INIT(name)				\
-}
+};									\
+	ASSERT_STATIC_STORAGE(name)
 
 #define DEFINE_PERCPU_RWSEM(name)		\
 	__DEFINE_PERCPU_RWSEM(name, /* not static */)
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index 6a1a7bae5f81..faf52c0c8dd3 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -8,6 +8,7 @@
 #ifndef _LINUX_RWSEM_H
 #define _LINUX_RWSEM_H
 
+#include <linux/compiler.h>
 #include <linux/linkage.h>
 
 #include <linux/types.h>
@@ -111,7 +112,8 @@ static inline void rwsem_assert_held_write_nolockdep(const struct rw_semaphore *
 	  __RWSEM_DEP_MAP_INIT(name) }
 
 #define DECLARE_RWSEM(name) \
-	struct rw_semaphore name = __RWSEM_INITIALIZER(name)
+	struct rw_semaphore name = __RWSEM_INITIALIZER(name);	\
+	ASSERT_STATIC_STORAGE(name)
 
 extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
 			 struct lock_class_key *key);
@@ -164,7 +166,8 @@ context_lock_struct(rw_semaphore) {
 	}
 
 #define DECLARE_RWSEM(lockname) \
-	struct rw_semaphore lockname = __RWSEM_INITIALIZER(lockname)
+	struct rw_semaphore lockname = __RWSEM_INITIALIZER(lockname);	\
+	ASSERT_STATIC_STORAGE(lockname)
 
 extern void  __init_rwsem(struct rw_semaphore *rwsem, const char *name,
 			  struct lock_class_key *key);
-- 
2.53.0