[PATCH] locking/rtmutex: Annotate API and implementation

[PATCH] locking/rtmutex: Annotate API and implementation

[Bart Van Assche]

Add lock context annotations to the rtmutex API and implementation and
enable lock context analysis.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 include/linux/rtmutex.h      | 22 +++++++++++++++-------
 kernel/locking/Makefile      |  1 +
 kernel/locking/rtmutex.c     |  4 ++++
 kernel/locking/rtmutex_api.c | 10 ++++++++--
 4 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 78e7e588817c..9e1f012f89db 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -56,6 +56,8 @@ static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock)
 #endif
 extern void rt_mutex_base_init(struct rt_mutex_base *rtb);
 
+context_lock_struct(rt_mutex);
+
 /**
  * The rt_mutex structure
  *
@@ -108,8 +110,10 @@ do { \
 extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key);
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
-extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass);
-extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock);
+extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
+	__acquires(lock);
+extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock)
+	__acquires(lock);
 #define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0)
 #define rt_mutex_lock_nest_lock(lock, nest_lock)			\
 	do {								\
@@ -118,15 +122,19 @@ extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *
 	} while (0)
 
 #else
-extern void rt_mutex_lock(struct rt_mutex *lock);
+extern void rt_mutex_lock(struct rt_mutex *lock) __acquires(lock);
 #define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock)
 #define rt_mutex_lock_nest_lock(lock, nest_lock) rt_mutex_lock(lock)
 #endif
 
-extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
-extern int rt_mutex_lock_killable(struct rt_mutex *lock);
-extern int rt_mutex_trylock(struct rt_mutex *lock);
+extern int rt_mutex_lock_interruptible(struct rt_mutex *lock)
+	__cond_acquires(0, lock);
+extern int rt_mutex_lock_killable(struct rt_mutex *lock)
+	__cond_acquires(0, lock);
+extern int rt_mutex_trylock(struct rt_mutex *lock)
+	__cond_acquires(true, lock);
 
-extern void rt_mutex_unlock(struct rt_mutex *lock);
+extern void rt_mutex_unlock(struct rt_mutex *lock)
+	__releases(lock);
 
 #endif
diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index cee1901d4cff..24dc00e12aa6 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -4,6 +4,7 @@
 KCOV_INSTRUMENT		:= n
 
 CONTEXT_ANALYSIS_mutex.o := y
+CONTEXT_ANALYSIS_rtmutex.o := y
 CONTEXT_ANALYSIS_rtmutex_api.o := y
 CONTEXT_ANALYSIS_ww_rt_mutex.o := y
 CONTEXT_ANALYSIS_rwsem.o := y
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 4f386ea6c792..9147d6a31b78 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -484,6 +484,7 @@ static __always_inline bool __waiter_less(struct rb_node *a, const struct rb_nod
 
 static __always_inline void
 rt_mutex_enqueue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter)
+	__must_hold(&lock->wait_lock)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -492,6 +493,7 @@ rt_mutex_enqueue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter)
 
 static __always_inline void
 rt_mutex_dequeue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter)
+	__must_hold(&lock->wait_lock)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -1092,6 +1094,7 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
 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)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -1319,6 +1322,7 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex_base *lock,
  */
 static void __sched mark_wakeup_next_waiter(struct rt_wake_q_head *wqh,
 					    struct rt_mutex_base *lock)
+	__must_hold(&lock->wait_lock)
 {
 	struct rt_mutex_waiter *waiter;
 
diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c
index 124219aea46e..09675b9cb9bd 100644
--- a/kernel/locking/rtmutex_api.c
+++ b/kernel/locking/rtmutex_api.c
@@ -41,6 +41,7 @@ static __always_inline int __rt_mutex_lock_common(struct rt_mutex *lock,
 						  unsigned int state,
 						  struct lockdep_map *nest_lock,
 						  unsigned int subclass)
+	__cond_acquires(0, lock)
 {
 	int ret;
 
@@ -66,12 +67,14 @@ EXPORT_SYMBOL(rt_mutex_base_init);
  * @subclass: the lockdep subclass
  */
 void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
+	__no_context_analysis /* ignoring the return value below is fine in this case */
 {
 	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, subclass);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);
 
 void __sched _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock)
+	__no_context_analysis /* ignoring the return value below is fine in this case */
 {
 	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, nest_lock, 0);
 }
@@ -157,6 +160,7 @@ void __sched rt_mutex_unlock(struct rt_mutex *lock)
 {
 	mutex_release(&lock->dep_map, _RET_IP_);
 	__rt_mutex_unlock(&lock->rtmutex);
+	__release(lock);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_unlock);
 
@@ -182,6 +186,7 @@ int __sched __rt_mutex_futex_trylock(struct rt_mutex_base *lock)
  */
 bool __sched __rt_mutex_futex_unlock(struct rt_mutex_base *lock,
 				     struct rt_wake_q_head *wqh)
+	__must_hold(&lock->wait_lock)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -312,6 +317,7 @@ int __sched __rt_mutex_start_proxy_lock(struct rt_mutex_base *lock,
 					struct rt_mutex_waiter *waiter,
 					struct task_struct *task,
 					struct wake_q_head *wake_q)
+	__must_hold(&lock->wait_lock)
 {
 	int ret;
 
@@ -526,7 +532,7 @@ static __always_inline int __mutex_lock_common(struct mutex *lock,
 					       unsigned int subclass,
 					       struct lockdep_map *nest_lock,
 					       unsigned long ip)
-	__acquires(lock) __no_context_analysis
+	__acquires(lock)
 {
 	int ret;
 
@@ -648,7 +654,7 @@ EXPORT_SYMBOL(mutex_trylock);
 #endif /* !CONFIG_DEBUG_LOCK_ALLOC */
 
 void __sched mutex_unlock(struct mutex *lock)
-	__releases(lock) __no_context_analysis
+	__releases(lock)
 {
 	mutex_release(&lock->dep_map, _RET_IP_);
 	__rt_mutex_unlock(&lock->rtmutex);

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

[Marco Elver]

On Sat, 2 May 2026 at 03:54, Bart Van Assche <bvanassche@acm.org> wrote:
>
> Add lock context annotations to the rtmutex API and implementation and
> enable lock context analysis.
>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>

If I'm not mistaken, Peter was working on this concurrently?
https://lore.kernel.org/all/20260121111213.851599178@infradead.org/ ?


> ---
>  include/linux/rtmutex.h      | 22 +++++++++++++++-------
>  kernel/locking/Makefile      |  1 +
>  kernel/locking/rtmutex.c     |  4 ++++
>  kernel/locking/rtmutex_api.c | 10 ++++++++--
>  4 files changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
> index 78e7e588817c..9e1f012f89db 100644
> --- a/include/linux/rtmutex.h
> +++ b/include/linux/rtmutex.h
> @@ -56,6 +56,8 @@ static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock)
>  #endif
>  extern void rt_mutex_base_init(struct rt_mutex_base *rtb);
>
> +context_lock_struct(rt_mutex);
> +
>  /**
>   * The rt_mutex structure
>   *
> @@ -108,8 +110,10 @@ do { \
>  extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key);
>
>  #ifdef CONFIG_DEBUG_LOCK_ALLOC
> -extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass);
> -extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock);
> +extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
> +       __acquires(lock);
> +extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock)
> +       __acquires(lock);
>  #define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0)
>  #define rt_mutex_lock_nest_lock(lock, nest_lock)                       \
>         do {                                                            \
> @@ -118,15 +122,19 @@ extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *
>         } while (0)
>
>  #else
> -extern void rt_mutex_lock(struct rt_mutex *lock);
> +extern void rt_mutex_lock(struct rt_mutex *lock) __acquires(lock);
>  #define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock)
>  #define rt_mutex_lock_nest_lock(lock, nest_lock) rt_mutex_lock(lock)
>  #endif
>
> -extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
> -extern int rt_mutex_lock_killable(struct rt_mutex *lock);
> -extern int rt_mutex_trylock(struct rt_mutex *lock);
> +extern int rt_mutex_lock_interruptible(struct rt_mutex *lock)
> +       __cond_acquires(0, lock);
> +extern int rt_mutex_lock_killable(struct rt_mutex *lock)
> +       __cond_acquires(0, lock);
> +extern int rt_mutex_trylock(struct rt_mutex *lock)
> +       __cond_acquires(true, lock);
>
> -extern void rt_mutex_unlock(struct rt_mutex *lock);
> +extern void rt_mutex_unlock(struct rt_mutex *lock)
> +       __releases(lock);
>
>  #endif
> diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
> index cee1901d4cff..24dc00e12aa6 100644
> --- a/kernel/locking/Makefile
> +++ b/kernel/locking/Makefile
> @@ -4,6 +4,7 @@
>  KCOV_INSTRUMENT                := n
>
>  CONTEXT_ANALYSIS_mutex.o := y
> +CONTEXT_ANALYSIS_rtmutex.o := y
>  CONTEXT_ANALYSIS_rtmutex_api.o := y
>  CONTEXT_ANALYSIS_ww_rt_mutex.o := y
>  CONTEXT_ANALYSIS_rwsem.o := y
> diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
> index 4f386ea6c792..9147d6a31b78 100644
> --- a/kernel/locking/rtmutex.c
> +++ b/kernel/locking/rtmutex.c
> @@ -484,6 +484,7 @@ static __always_inline bool __waiter_less(struct rb_node *a, const struct rb_nod
>
>  static __always_inline void
>  rt_mutex_enqueue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter)
> +       __must_hold(&lock->wait_lock)
>  {
>         lockdep_assert_held(&lock->wait_lock);
>
> @@ -492,6 +493,7 @@ rt_mutex_enqueue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter)
>
>  static __always_inline void
>  rt_mutex_dequeue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter)
> +       __must_hold(&lock->wait_lock)
>  {
>         lockdep_assert_held(&lock->wait_lock);
>
> @@ -1092,6 +1094,7 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
>  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)
>  {
>         lockdep_assert_held(&lock->wait_lock);
>
> @@ -1319,6 +1322,7 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex_base *lock,
>   */
>  static void __sched mark_wakeup_next_waiter(struct rt_wake_q_head *wqh,
>                                             struct rt_mutex_base *lock)
> +       __must_hold(&lock->wait_lock)
>  {
>         struct rt_mutex_waiter *waiter;
>
> diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c
> index 124219aea46e..09675b9cb9bd 100644
> --- a/kernel/locking/rtmutex_api.c
> +++ b/kernel/locking/rtmutex_api.c
> @@ -41,6 +41,7 @@ static __always_inline int __rt_mutex_lock_common(struct rt_mutex *lock,
>                                                   unsigned int state,
>                                                   struct lockdep_map *nest_lock,
>                                                   unsigned int subclass)
> +       __cond_acquires(0, lock)
>  {
>         int ret;
>
> @@ -66,12 +67,14 @@ EXPORT_SYMBOL(rt_mutex_base_init);
>   * @subclass: the lockdep subclass
>   */
>  void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
> +       __no_context_analysis /* ignoring the return value below is fine in this case */
>  {
>         __rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, subclass);
>  }
>  EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);
>
>  void __sched _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock)
> +       __no_context_analysis /* ignoring the return value below is fine in this case */
>  {
>         __rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, nest_lock, 0);
>  }
> @@ -157,6 +160,7 @@ void __sched rt_mutex_unlock(struct rt_mutex *lock)
>  {
>         mutex_release(&lock->dep_map, _RET_IP_);
>         __rt_mutex_unlock(&lock->rtmutex);
> +       __release(lock);
>  }
>  EXPORT_SYMBOL_GPL(rt_mutex_unlock);
>
> @@ -182,6 +186,7 @@ int __sched __rt_mutex_futex_trylock(struct rt_mutex_base *lock)
>   */
>  bool __sched __rt_mutex_futex_unlock(struct rt_mutex_base *lock,
>                                      struct rt_wake_q_head *wqh)
> +       __must_hold(&lock->wait_lock)
>  {
>         lockdep_assert_held(&lock->wait_lock);
>
> @@ -312,6 +317,7 @@ int __sched __rt_mutex_start_proxy_lock(struct rt_mutex_base *lock,
>                                         struct rt_mutex_waiter *waiter,
>                                         struct task_struct *task,
>                                         struct wake_q_head *wake_q)
> +       __must_hold(&lock->wait_lock)
>  {
>         int ret;
>
> @@ -526,7 +532,7 @@ static __always_inline int __mutex_lock_common(struct mutex *lock,
>                                                unsigned int subclass,
>                                                struct lockdep_map *nest_lock,
>                                                unsigned long ip)
> -       __acquires(lock) __no_context_analysis
> +       __acquires(lock)
>  {
>         int ret;
>
> @@ -648,7 +654,7 @@ EXPORT_SYMBOL(mutex_trylock);
>  #endif /* !CONFIG_DEBUG_LOCK_ALLOC */
>
>  void __sched mutex_unlock(struct mutex *lock)
> -       __releases(lock) __no_context_analysis
> +       __releases(lock)
>  {
>         mutex_release(&lock->dep_map, _RET_IP_);
>         __rt_mutex_unlock(&lock->rtmutex);

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

[Bart Van Assche]

On 5/4/26 8:00 AM, Marco Elver wrote:
> On Sat, 2 May 2026 at 03:54, Bart Van Assche <bvanassche@acm.org> wrote:
>>
>> Add lock context annotations to the rtmutex API and implementation and
>> enable lock context analysis.
>>
>> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> 
> If I'm not mistaken, Peter was working on this concurrently?
> https://lore.kernel.org/all/20260121111213.851599178@infradead.org/ ?

Hmm ... I don't see CONTEXT_ANALYSIS_rtmutex.o := y in any of Peter's
rtmutext patches. Did I perhaps overlook something? According to the
results of this query my patch is the first patch that enables context
analysis for rtmutex.c:
https://lore.kernel.org/all/?q=CONTEXT_ANALYSIS_rtmutex

Thanks,

Bart.

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@acm.org>

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;
 

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

[Bart Van Assche]

On 5/4/26 11:39 AM, Peter Zijlstra wrote:
> This does not build, I need at least the below, but then PREEMPT_RT is
> still not happy.
Apparently I had tested my patch with PREEMPT_RT=n only. The patch below
should support both PREEMPT_RT=n and PREEMPT_RT=y:

---
  include/linux/rtmutex.h      | 22 +++++++++++++++-------
  kernel/locking/Makefile      |  1 +
  kernel/locking/rtmutex.c     |  5 +++++
  kernel/locking/rtmutex_api.c |  6 ++++++
  4 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 78e7e588817c..9e1f012f89db 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -56,6 +56,8 @@ static inline struct task_struct 
*rt_mutex_owner(struct rt_mutex_base *lock)
  #endif
  extern void rt_mutex_base_init(struct rt_mutex_base *rtb);

+context_lock_struct(rt_mutex);
+
  /**
   * The rt_mutex structure
   *
@@ -108,8 +110,10 @@ do { \
  extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, 
struct lock_class_key *key);

  #ifdef CONFIG_DEBUG_LOCK_ALLOC
-extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int 
subclass);
-extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct 
lockdep_map *nest_lock);
+extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int 
subclass)
+	__acquires(lock);
+extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct 
lockdep_map *nest_lock)
+	__acquires(lock);
  #define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0)
  #define rt_mutex_lock_nest_lock(lock, nest_lock)			\
  	do {								\
@@ -118,15 +122,19 @@ extern void _rt_mutex_lock_nest_lock(struct 
rt_mutex *lock, struct lockdep_map *
  	} while (0)

  #else
-extern void rt_mutex_lock(struct rt_mutex *lock);
+extern void rt_mutex_lock(struct rt_mutex *lock) __acquires(lock);
  #define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock)
  #define rt_mutex_lock_nest_lock(lock, nest_lock) rt_mutex_lock(lock)
  #endif

-extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
-extern int rt_mutex_lock_killable(struct rt_mutex *lock);
-extern int rt_mutex_trylock(struct rt_mutex *lock);
+extern int rt_mutex_lock_interruptible(struct rt_mutex *lock)
+	__cond_acquires(0, lock);
+extern int rt_mutex_lock_killable(struct rt_mutex *lock)
+	__cond_acquires(0, lock);
+extern int rt_mutex_trylock(struct rt_mutex *lock)
+	__cond_acquires(true, lock);

-extern void rt_mutex_unlock(struct rt_mutex *lock);
+extern void rt_mutex_unlock(struct rt_mutex *lock)
+	__releases(lock);

  #endif
diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index cee1901d4cff..24dc00e12aa6 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -4,6 +4,7 @@
  KCOV_INSTRUMENT		:= n

  CONTEXT_ANALYSIS_mutex.o := y
+CONTEXT_ANALYSIS_rtmutex.o := y
  CONTEXT_ANALYSIS_rtmutex_api.o := y
  CONTEXT_ANALYSIS_ww_rt_mutex.o := y
  CONTEXT_ANALYSIS_rwsem.o := y
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 4f386ea6c792..69759fde7d10 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -484,6 +484,7 @@ static __always_inline bool __waiter_less(struct 
rb_node *a, const struct rb_nod

  static __always_inline void
  rt_mutex_enqueue(struct rt_mutex_base *lock, struct rt_mutex_waiter 
*waiter)
+	__must_hold(&lock->wait_lock)
  {
  	lockdep_assert_held(&lock->wait_lock);

@@ -492,6 +493,7 @@ rt_mutex_enqueue(struct rt_mutex_base *lock, struct 
rt_mutex_waiter *waiter)

  static __always_inline void
  rt_mutex_dequeue(struct rt_mutex_base *lock, struct rt_mutex_waiter 
*waiter)
+	__must_hold(&lock->wait_lock)
  {
  	lockdep_assert_held(&lock->wait_lock);

@@ -1092,6 +1094,7 @@ static int __sched 
rt_mutex_adjust_prio_chain(struct task_struct *task,
  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)
  {
  	lockdep_assert_held(&lock->wait_lock);

@@ -1319,6 +1322,7 @@ static int __sched task_blocks_on_rt_mutex(struct 
rt_mutex_base *lock,
   */
  static void __sched mark_wakeup_next_waiter(struct rt_wake_q_head *wqh,
  					    struct rt_mutex_base *lock)
+	__must_hold(&lock->wait_lock)
  {
  	struct rt_mutex_waiter *waiter;

@@ -1479,6 +1483,7 @@ static void __sched rt_mutex_slowunlock(struct 
rt_mutex_base *lock)
  }

  static __always_inline void __rt_mutex_unlock(struct rt_mutex_base *lock)
+	__no_context_analysis
  {
  	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
  		return;
diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c
index 124219aea46e..23ad997ddd65 100644
--- a/kernel/locking/rtmutex_api.c
+++ b/kernel/locking/rtmutex_api.c
@@ -41,6 +41,7 @@ static __always_inline int 
__rt_mutex_lock_common(struct rt_mutex *lock,
  						  unsigned int state,
  						  struct lockdep_map *nest_lock,
  						  unsigned int subclass)
+	__cond_acquires(0, lock)
  {
  	int ret;

@@ -66,12 +67,14 @@ EXPORT_SYMBOL(rt_mutex_base_init);
   * @subclass: the lockdep subclass
   */
  void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int 
subclass)
+	__no_context_analysis /* ignoring the return value below is fine in 
this case */
  {
  	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, subclass);
  }
  EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);

  void __sched _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct 
lockdep_map *nest_lock)
+	__no_context_analysis /* ignoring the return value below is fine in 
this case */
  {
  	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, nest_lock, 0);
  }
@@ -157,6 +160,7 @@ void __sched rt_mutex_unlock(struct rt_mutex *lock)
  {
  	mutex_release(&lock->dep_map, _RET_IP_);
  	__rt_mutex_unlock(&lock->rtmutex);
+	__release(lock);
  }
  EXPORT_SYMBOL_GPL(rt_mutex_unlock);

@@ -182,6 +186,7 @@ int __sched __rt_mutex_futex_trylock(struct 
rt_mutex_base *lock)
   */
  bool __sched __rt_mutex_futex_unlock(struct rt_mutex_base *lock,
  				     struct rt_wake_q_head *wqh)
+	__must_hold(&lock->wait_lock)
  {
  	lockdep_assert_held(&lock->wait_lock);

@@ -312,6 +317,7 @@ int __sched __rt_mutex_start_proxy_lock(struct 
rt_mutex_base *lock,
  					struct rt_mutex_waiter *waiter,
  					struct task_struct *task,
  					struct wake_q_head *wake_q)
+	__must_hold(&lock->wait_lock)
  {
  	int ret;

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

[Peter Zijlstra]

On Mon, May 04, 2026 at 01:56:03PM +0200, Bart Van Assche wrote:
> On 5/4/26 11:39 AM, Peter Zijlstra wrote:
> > This does not build, I need at least the below, but then PREEMPT_RT is
> > still not happy.
> Apparently I had tested my patch with PREEMPT_RT=n only. The patch below
> should support both PREEMPT_RT=n and PREEMPT_RT=y:

Is whitespace mangled :/