Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

Pull locking fixes from Ingo Molnar:
 "Tone down mutex debugging complaints, and annotate/fix spinlock
  debugging data accesses for KCSAN"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "locking/mutex: Complain upon mutex API misuse in IRQ contexts"
  locking/spinlock/debug: Fix various data races

diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 54cc5f9286e93ee708fea396651ff3f53d1dbb1a..5352ce50a97e309b5bf8cdd2059378b17a8f14ec 100644 (file)
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -733,9 +733,6 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
  */
 void __sched mutex_unlock(struct mutex *lock)
 {
-#ifdef CONFIG_DEBUG_MUTEXES
-       WARN_ON(in_interrupt());
-#endif
 #ifndef CONFIG_DEBUG_LOCK_ALLOC
        if (__mutex_unlock_fast(lock))
                return;
@@ -1416,7 +1413,6 @@ int __sched mutex_trylock(struct mutex *lock)
 
 #ifdef CONFIG_DEBUG_MUTEXES
        DEBUG_LOCKS_WARN_ON(lock->magic != lock);
-       WARN_ON(in_interrupt());
 #endif
 
        locked = __mutex_trylock(lock);

diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c
index 399669f7eba8e9569830e1c35b7f37c3c712025b..472dd462a40ca91ec62a773cf8fde19a25c72994 100644 (file)
--- a/kernel/locking/spinlock_debug.c
+++ b/kernel/locking/spinlock_debug.c
@@ -51,19 +51,19 @@ EXPORT_SYMBOL(__rwlock_init);
 
 static void spin_dump(raw_spinlock_t *lock, const char *msg)
 {
-       struct task_struct *owner = NULL;
+       struct task_struct *owner = READ_ONCE(lock->owner);
 
-       if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
-               owner = lock->owner;
+       if (owner == SPINLOCK_OWNER_INIT)
+               owner = NULL;
        printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
                msg, raw_smp_processor_id(),
                current->comm, task_pid_nr(current));
        printk(KERN_EMERG " lock: %pS, .magic: %08x, .owner: %s/%d, "
                        ".owner_cpu: %d\n",
-               lock, lock->magic,
+               lock, READ_ONCE(lock->magic),
                owner ? owner->comm : "<none>",
                owner ? task_pid_nr(owner) : -1,
-               lock->owner_cpu);
+               READ_ONCE(lock->owner_cpu));
        dump_stack();
 }
 
@@ -80,16 +80,16 @@ static void spin_bug(raw_spinlock_t *lock, const char *msg)
 static inline void
 debug_spin_lock_before(raw_spinlock_t *lock)
 {
-       SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
-       SPIN_BUG_ON(lock->owner == current, lock, "recursion");
-       SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
+       SPIN_BUG_ON(READ_ONCE(lock->magic) != SPINLOCK_MAGIC, lock, "bad magic");
+       SPIN_BUG_ON(READ_ONCE(lock->owner) == current, lock, "recursion");
+       SPIN_BUG_ON(READ_ONCE(lock->owner_cpu) == raw_smp_processor_id(),
                                                        lock, "cpu recursion");
 }
 
 static inline void debug_spin_lock_after(raw_spinlock_t *lock)
 {
-       lock->owner_cpu = raw_smp_processor_id();
-       lock->owner = current;
+       WRITE_ONCE(lock->owner_cpu, raw_smp_processor_id());
+       WRITE_ONCE(lock->owner, current);
 }
 
 static inline void debug_spin_unlock(raw_spinlock_t *lock)
@@ -99,8 +99,8 @@ static inline void debug_spin_unlock(raw_spinlock_t *lock)
        SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
        SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
                                                        lock, "wrong CPU");
-       lock->owner = SPINLOCK_OWNER_INIT;
-       lock->owner_cpu = -1;
+       WRITE_ONCE(lock->owner, SPINLOCK_OWNER_INIT);
+       WRITE_ONCE(lock->owner_cpu, -1);
 }
 
 /*
@@ -187,8 +187,8 @@ static inline void debug_write_lock_before(rwlock_t *lock)
 
 static inline void debug_write_lock_after(rwlock_t *lock)
 {
-       lock->owner_cpu = raw_smp_processor_id();
-       lock->owner = current;
+       WRITE_ONCE(lock->owner_cpu, raw_smp_processor_id());
+       WRITE_ONCE(lock->owner, current);
 }
 
 static inline void debug_write_unlock(rwlock_t *lock)
@@ -197,8 +197,8 @@ static inline void debug_write_unlock(rwlock_t *lock)
        RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
        RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
                                                        lock, "wrong CPU");
-       lock->owner = SPINLOCK_OWNER_INIT;
-       lock->owner_cpu = -1;
+       WRITE_ONCE(lock->owner, SPINLOCK_OWNER_INIT);
+       WRITE_ONCE(lock->owner_cpu, -1);
 }
 
 void do_raw_write_lock(rwlock_t *lock)