Merge tag 'locking_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Borislav Petkov:
 "Lots of cleanups and preparation. Highlights:

   - futex: Cleanup and remove runtime futex_cmpxchg detection

   - rtmutex: Some fixes for the PREEMPT_RT locking infrastructure

   - kcsan: Share owner_on_cpu() between mutex,rtmutex and rwsem and
     annotate the racy owner->on_cpu access *once*.

   - atomic64: Dead-Code-Elemination"

[ Description above by Peter Zijlstra ]

* tag 'locking_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/atomic: atomic64: Remove unusable atomic ops
  futex: Fix additional regressions
  locking: Allow to include asm/spinlock_types.h from linux/spinlock_types_raw.h
  x86/mm: Include spinlock_t definition in pgtable.
  locking: Mark racy reads of owner->on_cpu
  locking: Make owner_on_cpu() into <linux/sched.h>
  lockdep/selftests: Adapt ww-tests for PREEMPT_RT
  lockdep/selftests: Skip the softirq related tests on PREEMPT_RT
  lockdep/selftests: Unbalanced migrate_disable() & rcu_read_lock().
  lockdep/selftests: Avoid using local_lock_{acquire|release}().
  lockdep: Remove softirq accounting on PREEMPT_RT.
  locking/rtmutex: Add rt_mutex_lock_nest_lock() and rt_mutex_lock_killable().
  locking/rtmutex: Squash self-deadlock check for ww_rt_mutex.
  locking: Remove rt_rwlock_is_contended().
  sched: Trigger warning if ->migration_disabled counter underflows.
  futex: Fix sparc32/m68k/nds32 build regression
  futex: Remove futex_cmpxchg detection
  futex: Ensure futex_atomic_cmpxchg_inatomic() is present
  kernel/locking: Use a pointer in ww_mutex_trylock().

kernel/locking/lockdep.c

@@ -5485,6 +5485,7 @@ static noinstr void check_flags(unsigned long flags)
 		}
 	}
 
+#ifndef CONFIG_PREEMPT_RT
 	/*
 	 * We dont accurately track softirq state in e.g.
 	 * hardirq contexts (such as on 4KSTACKS), so only
@@ -5499,6 +5500,7 @@ static noinstr void check_flags(unsigned long flags)
 			DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
 		}
 	}
+#endif
 
 	if (!debug_locks)
 		print_irqtrace_events(current);

kernel/locking/mutex.c

@@ -367,8 +367,7 @@ bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner,
 		/*
 		 * Use vcpu_is_preempted to detect lock holder preemption issue.
 		 */
-		if (!owner->on_cpu || need_resched() ||
-				vcpu_is_preempted(task_cpu(owner))) {
+		if (!owner_on_cpu(owner) || need_resched()) {
 			ret = false;
 			break;
 		}
@@ -403,14 +402,8 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
 	 * structure won't go away during the spinning period.
 	 */
 	owner = __mutex_owner(lock);
-
-	/*
-	 * As lock holder preemption issue, we both skip spinning if task is not
-	 * on cpu or its cpu is preempted
-	 */
-
 	if (owner)
-		retval = owner->on_cpu && !vcpu_is_preempted(task_cpu(owner));
+		retval = owner_on_cpu(owner);
 
 	/*
 	 * If lock->owner is not set, the mutex has been released. Return true

kernel/locking/rtmutex.c

@@ -1103,8 +1103,11 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex_base *lock,
 	 * the other will detect the deadlock and return -EDEADLOCK,
 	 * which is wrong, as the other waiter is not in a deadlock
 	 * situation.
+	 *
+	 * Except for ww_mutex, in that case the chain walk must already deal
+	 * with spurious cycles, see the comments at [3] and [6].
 	 */
-	if (owner == task)
+	if (owner == task && !(build_ww_mutex() && ww_ctx))
 		return -EDEADLK;
 
 	raw_spin_lock(&task->pi_lock);
@@ -1379,9 +1382,8 @@ static bool rtmutex_spin_on_owner(struct rt_mutex_base *lock,
 		 *    for CONFIG_PREEMPT_RCU=y)
 		 *  - the VCPU on which owner runs is preempted
 		 */
-		if (!owner->on_cpu || need_resched() ||
-		    !rt_mutex_waiter_is_top_waiter(lock, waiter) ||
-		    vcpu_is_preempted(task_cpu(owner))) {
+		if (!owner_on_cpu(owner) || need_resched() ||
+		    !rt_mutex_waiter_is_top_waiter(lock, waiter)) {
 			res = false;
 			break;
 		}

kernel/locking/rtmutex_api.c

@@ -21,12 +21,13 @@ int max_lock_depth = 1024;
  */
 static __always_inline int __rt_mutex_lock_common(struct rt_mutex *lock,
 						  unsigned int state,
+						  struct lockdep_map *nest_lock,
 						  unsigned int subclass)
 {
 	int ret;
 
 	might_sleep();
-	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, _RET_IP_);
 	ret = __rt_mutex_lock(&lock->rtmutex, state);
 	if (ret)
 		mutex_release(&lock->dep_map, _RET_IP_);
@@ -48,10 +49,16 @@ EXPORT_SYMBOL(rt_mutex_base_init);
  */
 void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
 {
-	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass);
+	__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)
+{
+	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, nest_lock, 0);
+}
+EXPORT_SYMBOL_GPL(_rt_mutex_lock_nest_lock);
+
 #else /* !CONFIG_DEBUG_LOCK_ALLOC */
 
 /**
@@ -61,7 +68,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);
  */
 void __sched rt_mutex_lock(struct rt_mutex *lock)
 {
-	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0);
+	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, 0);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock);
 #endif
@@ -77,10 +84,25 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock);
  */
 int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock)
 {
-	return __rt_mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0);
+	return __rt_mutex_lock_common(lock, TASK_INTERRUPTIBLE, NULL, 0);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
 
+/**
+ * rt_mutex_lock_killable - lock a rt_mutex killable
+ *
+ * @lock:		the rt_mutex to be locked
+ *
+ * Returns:
+ *  0		on success
+ * -EINTR	when interrupted by a signal
+ */
+int __sched rt_mutex_lock_killable(struct rt_mutex *lock)
+{
+	return __rt_mutex_lock_common(lock, TASK_KILLABLE, NULL, 0);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_killable);
+
 /**
  * rt_mutex_trylock - try to lock a rt_mutex
  *

kernel/locking/rwsem.c

@@ -658,15 +658,6 @@ static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem)
 	return false;
 }
 
-static inline bool owner_on_cpu(struct task_struct *owner)
-{
-	/*
-	 * As lock holder preemption issue, we both skip spinning if
-	 * task is not on cpu or its cpu is preempted
-	 */
-	return owner->on_cpu && !vcpu_is_preempted(task_cpu(owner));
-}
-
 static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
 {
 	struct task_struct *owner;

kernel/locking/spinlock_rt.c

@@ -257,12 +257,6 @@ void __sched rt_write_unlock(rwlock_t *rwlock)
 }
 EXPORT_SYMBOL(rt_write_unlock);
 
-int __sched rt_rwlock_is_contended(rwlock_t *rwlock)
-{
-	return rw_base_is_contended(&rwlock->rwbase);
-}
-EXPORT_SYMBOL(rt_rwlock_is_contended);
-
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 void __rt_rwlock_init(rwlock_t *rwlock, const char *name,
 		      struct lock_class_key *key)

kernel/locking/ww_rt_mutex.c

@@ -26,7 +26,7 @@ int ww_mutex_trylock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx)
 
 	if (__rt_mutex_trylock(&rtm->rtmutex)) {
 		ww_mutex_set_context_fastpath(lock, ww_ctx);
-		mutex_acquire_nest(&rtm->dep_map, 0, 1, ww_ctx->dep_map, _RET_IP_);
+		mutex_acquire_nest(&rtm->dep_map, 0, 1, &ww_ctx->dep_map, _RET_IP_);
 		return 1;
 	}