Re: [PATCH] locking/rtmutex: Annotate API and implementation

[Peter Zijlstra]

On Fri, May 01, 2026 at 06:53:49PM -0700, Bart Van Assche wrote:
> Add lock context annotations to the rtmutex API and implementation and
> enable lock context analysis.
> 
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>

This does not build, I need at least the below, but then PREEMPT_RT is
still not happy.

---
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -20,7 +20,7 @@
 
 extern int max_lock_depth;
 
-struct rt_mutex_base {
+context_lock_struct(rt_mutex_base) {
 	raw_spinlock_t		wait_lock;
 	struct rb_root_cached   waiters __guarded_by(&wait_lock);
 	struct task_struct	*owner  __guarded_by(&wait_lock);
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -314,6 +314,7 @@ static __always_inline bool rt_mutex_cmp
 static int __sched rt_mutex_slowtrylock(struct rt_mutex_base *lock);
 
 static __always_inline bool rt_mutex_try_acquire(struct rt_mutex_base *lock)
+	__cond_acquires(true, lock)
 {
 	/*
 	 * With debug enabled rt_mutex_cmpxchg trylock() will always fail.
@@ -1095,6 +1096,7 @@ static int __sched
 try_to_take_rt_mutex(struct rt_mutex_base *lock, struct task_struct *task,
 		     struct rt_mutex_waiter *waiter)
 	__must_hold(&lock->wait_lock)
+	__cond_acquires(nonzero, lock)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -1625,6 +1627,7 @@ static int __sched rt_mutex_slowlock_blo
 					   struct rt_mutex_waiter *waiter,
 					   struct wake_q_head *wake_q)
 	__releases(&lock->wait_lock) __acquires(&lock->wait_lock)
+	__cond_acquires(0, lock)
 {
 	struct rt_mutex *rtm = container_of(lock, struct rt_mutex, rtmutex);
 	struct task_struct *owner;
@@ -1715,6 +1718,7 @@ static int __sched __rt_mutex_slowlock(s
 				       struct rt_mutex_waiter *waiter,
 				       struct wake_q_head *wake_q)
 	__must_hold(&lock->wait_lock)
+	__cond_acquires(0, lock)
 {
 	struct rt_mutex *rtm = container_of(lock, struct rt_mutex, rtmutex);
 	struct ww_mutex *ww = ww_container_of(rtm);
@@ -1773,6 +1777,7 @@ static inline int __rt_mutex_slowlock_lo
 					     unsigned int state,
 					     struct wake_q_head *wake_q)
 	__must_hold(&lock->wait_lock)
+	__cond_acquires(0, lock)
 {
 	struct rt_mutex_waiter waiter;
 	int ret;
@@ -1797,6 +1802,7 @@ static inline int __rt_mutex_slowlock_lo
 static int __sched rt_mutex_slowlock(struct rt_mutex_base *lock,
 				     struct ww_acquire_ctx *ww_ctx,
 				     unsigned int state)
+	__cond_acquires(0, lock)
 {
 	DEFINE_WAKE_Q(wake_q);
 	unsigned long flags;
@@ -1829,6 +1835,7 @@ static int __sched rt_mutex_slowlock(str
 
 static __always_inline int __rt_mutex_lock(struct rt_mutex_base *lock,
 					   unsigned int state)
+	__cond_acquires(0, lock)
 {
 	lockdep_assert(!current->pi_blocked_on);
 
--- a/kernel/locking/rtmutex_api.c
+++ b/kernel/locking/rtmutex_api.c
@@ -88,6 +88,7 @@ EXPORT_SYMBOL_GPL(_rt_mutex_lock_nest_lo
  * @lock: the rt_mutex to be locked
  */
 void __sched rt_mutex_lock(struct rt_mutex *lock)
+	__no_context_analysis /* ignoring the return value below is fine in this case */
 {
 	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, 0);
 }
@@ -532,7 +533,7 @@ static __always_inline int __mutex_lock_
 					       unsigned int subclass,
 					       struct lockdep_map *nest_lock,
 					       unsigned long ip)
-	__acquires(lock)
+	__cond_acquires(0, lock)
 {
 	int ret;