1 files changed, 49 insertions, 34 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index b911adceb2c4..8e3c3ffe1b9a 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -150,7 +150,8 @@ static struct futex_hash_bucket *hash_futex(union futex_key *key)
  */
 static inline int match_futex(union futex_key *key1, union futex_key *key2)
 {
-	return (key1->both.word == key2->both.word
+	return (key1 && key2
+		&& key1->both.word == key2->both.word
 		&& key1->both.ptr == key2->both.ptr
 		&& key1->both.offset == key2->both.offset);
 }
@@ -303,8 +304,14 @@ void put_futex_key(int fshared, union futex_key *key)
  */
 static int fault_in_user_writeable(u32 __user *uaddr)
 {
-	int ret = get_user_pages(current, current->mm, (unsigned long)uaddr,
-				 1, 1, 0, NULL, NULL);
+	struct mm_struct *mm = current->mm;
+	int ret;
+
+	down_read(&mm->mmap_sem);
+	ret = get_user_pages(current, mm, (unsigned long)uaddr,
+			     1, 1, 0, NULL, NULL);
+	up_read(&mm->mmap_sem);
+
 	return ret < 0 ? ret : 0;
 }
 
@@ -396,9 +403,9 @@ static void free_pi_state(struct futex_pi_state *pi_state)
 	 * and has cleaned up the pi_state already
 	 */
 	if (pi_state->owner) {
-		spin_lock_irq(&pi_state->owner->pi_lock);
+		raw_spin_lock_irq(&pi_state->owner->pi_lock);
 		list_del_init(&pi_state->list);
-		spin_unlock_irq(&pi_state->owner->pi_lock);
+		raw_spin_unlock_irq(&pi_state->owner->pi_lock);
 
 		rt_mutex_proxy_unlock(&pi_state->pi_mutex, pi_state->owner);
 	}
@@ -463,18 +470,18 @@ void exit_pi_state_list(struct task_struct *curr)
 	 * pi_state_list anymore, but we have to be careful
 	 * versus waiters unqueueing themselves:
 	 */
-	spin_lock_irq(&curr->pi_lock);
+	raw_spin_lock_irq(&curr->pi_lock);
 	while (!list_empty(head)) {
 
 		next = head->next;
 		pi_state = list_entry(next, struct futex_pi_state, list);
 		key = pi_state->key;
 		hb = hash_futex(&key);
-		spin_unlock_irq(&curr->pi_lock);
+		raw_spin_unlock_irq(&curr->pi_lock);
 
 		spin_lock(&hb->lock);
 
-		spin_lock_irq(&curr->pi_lock);
+		raw_spin_lock_irq(&curr->pi_lock);
 		/*
 		 * We dropped the pi-lock, so re-check whether this
 		 * task still owns the PI-state:
@@ -488,15 +495,15 @@ void exit_pi_state_list(struct task_struct *curr)
 		WARN_ON(list_empty(&pi_state->list));
 		list_del_init(&pi_state->list);
 		pi_state->owner = NULL;
-		spin_unlock_irq(&curr->pi_lock);
+		raw_spin_unlock_irq(&curr->pi_lock);
 
 		rt_mutex_unlock(&pi_state->pi_mutex);
 
 		spin_unlock(&hb->lock);
 
-		spin_lock_irq(&curr->pi_lock);
+		raw_spin_lock_irq(&curr->pi_lock);
 	}
-	spin_unlock_irq(&curr->pi_lock);
+	raw_spin_unlock_irq(&curr->pi_lock);
 }
 
 static int
@@ -551,7 +558,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
 	 * change of the task flags, we do this protected by
 	 * p->pi_lock:
 	 */
-	spin_lock_irq(&p->pi_lock);
+	raw_spin_lock_irq(&p->pi_lock);
 	if (unlikely(p->flags & PF_EXITING)) {
 		/*
 		 * The task is on the way out. When PF_EXITPIDONE is
@@ -560,7 +567,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
 		 */
 		int ret = (p->flags & PF_EXITPIDONE) ? -ESRCH : -EAGAIN;
 
-		spin_unlock_irq(&p->pi_lock);
+		raw_spin_unlock_irq(&p->pi_lock);
 		put_task_struct(p);
 		return ret;
 	}
@@ -579,7 +586,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
 	WARN_ON(!list_empty(&pi_state->list));
 	list_add(&pi_state->list, &p->pi_state_list);
 	pi_state->owner = p;
-	spin_unlock_irq(&p->pi_lock);
+	raw_spin_unlock_irq(&p->pi_lock);
 
 	put_task_struct(p);
 
@@ -753,7 +760,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this)
 	if (!pi_state)
 		return -EINVAL;
 
-	spin_lock(&pi_state->pi_mutex.wait_lock);
+	raw_spin_lock(&pi_state->pi_mutex.wait_lock);
 	new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
 
 	/*
@@ -782,23 +789,23 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this)
 		else if (curval != uval)
 			ret = -EINVAL;
 		if (ret) {
-			spin_unlock(&pi_state->pi_mutex.wait_lock);
+			raw_spin_unlock(&pi_state->pi_mutex.wait_lock);
 			return ret;
 		}
 	}
 
-	spin_lock_irq(&pi_state->owner->pi_lock);
+	raw_spin_lock_irq(&pi_state->owner->pi_lock);
 	WARN_ON(list_empty(&pi_state->list));
 	list_del_init(&pi_state->list);
-	spin_unlock_irq(&pi_state->owner->pi_lock);
+	raw_spin_unlock_irq(&pi_state->owner->pi_lock);
 
-	spin_lock_irq(&new_owner->pi_lock);
+	raw_spin_lock_irq(&new_owner->pi_lock);
 	WARN_ON(!list_empty(&pi_state->list));
 	list_add(&pi_state->list, &new_owner->pi_state_list);
 	pi_state->owner = new_owner;
-	spin_unlock_irq(&new_owner->pi_lock);
+	raw_spin_unlock_irq(&new_owner->pi_lock);
 
-	spin_unlock(&pi_state->pi_mutex.wait_lock);
+	raw_spin_unlock(&pi_state->pi_mutex.wait_lock);
 	rt_mutex_unlock(&pi_state->pi_mutex);
 
 	return 0;
@@ -916,8 +923,8 @@ retry:
 	hb1 = hash_futex(&key1);
 	hb2 = hash_futex(&key2);
 
-	double_lock_hb(hb1, hb2);
 retry_private:
+	double_lock_hb(hb1, hb2);
 	op_ret = futex_atomic_op_inuser(op, uaddr2);
 	if (unlikely(op_ret < 0)) {
 
@@ -1003,7 +1010,7 @@ void requeue_futex(struct futex_q *q, struct futex_hash_bucket *hb1,
 		plist_add(&q->list, &hb2->chain);
 		q->lock_ptr = &hb2->lock;
 #ifdef CONFIG_DEBUG_PI_LIST
-		q->list.plist.lock = &hb2->lock;
+		q->list.plist.spinlock = &hb2->lock;
 #endif
 	}
 	get_futex_key_refs(key2);
@@ -1028,7 +1035,6 @@ static inline
 void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key,
 			   struct futex_hash_bucket *hb)
 {
-	drop_futex_key_refs(&q->key);
 	get_futex_key_refs(key);
 	q->key = *key;
 
@@ -1040,7 +1046,7 @@ void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key,
 
 	q->lock_ptr = &hb->lock;
 #ifdef CONFIG_DEBUG_PI_LIST
-	q->list.plist.lock = &hb->lock;
+	q->list.plist.spinlock = &hb->lock;
 #endif
 
 	wake_up_state(q->task, TASK_NORMAL);
@@ -1226,6 +1232,7 @@ retry_private:
 		 */
 		if (ret == 1) {
 			WARN_ON(pi_state);
+			drop_count++;
 			task_count++;
 			ret = get_futex_value_locked(&curval2, uaddr2);
 			if (!ret)
@@ -1304,6 +1311,7 @@ retry_private:
 			if (ret == 1) {
 				/* We got the lock. */
 				requeue_pi_wake_futex(this, &key2, hb2);
+				drop_count++;
 				continue;
 			} else if (ret) {
 				/* -EDEADLK */
@@ -1386,7 +1394,7 @@ static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb)
 
 	plist_node_init(&q->list, prio);
 #ifdef CONFIG_DEBUG_PI_LIST
-	q->list.plist.lock = &hb->lock;
+	q->list.plist.spinlock = &hb->lock;
 #endif
 	plist_add(&q->list, &hb->chain);
 	q->task = current;
@@ -1521,18 +1529,18 @@ retry:
 	 * itself.
 	 */
 	if (pi_state->owner != NULL) {
-		spin_lock_irq(&pi_state->owner->pi_lock);
+		raw_spin_lock_irq(&pi_state->owner->pi_lock);
 		WARN_ON(list_empty(&pi_state->list));
 		list_del_init(&pi_state->list);
-		spin_unlock_irq(&pi_state->owner->pi_lock);
+		raw_spin_unlock_irq(&pi_state->owner->pi_lock);
 	}
 
 	pi_state->owner = newowner;
 
-	spin_lock_irq(&newowner->pi_lock);
+	raw_spin_lock_irq(&newowner->pi_lock);
 	WARN_ON(!list_empty(&pi_state->list));
 	list_add(&pi_state->list, &newowner->pi_state_list);
-	spin_unlock_irq(&newowner->pi_lock);
+	raw_spin_unlock_irq(&newowner->pi_lock);
 	return 0;
 
 	/*
@@ -1791,6 +1799,7 @@ static int futex_wait(u32 __user *uaddr, int fshared,
 					     current->timer_slack_ns);
 	}
 
+retry:
 	/* Prepare to wait on uaddr. */
 	ret = futex_wait_setup(uaddr, val, fshared, &q, &hb);
 	if (ret)
@@ -1808,9 +1817,14 @@ static int futex_wait(u32 __user *uaddr, int fshared,
 		goto out_put_key;
 
 	/*
-	 * We expect signal_pending(current), but another thread may
-	 * have handled it for us already.
+	 * We expect signal_pending(current), but we might be the
+	 * victim of a spurious wakeup as well.
 	 */
+	if (!signal_pending(current)) {
+		put_futex_key(fshared, &q.key);
+		goto retry;
+	}
+
 	ret = -ERESTARTSYS;
 	if (!abs_time)
 		goto out_put_key;
@@ -2117,11 +2131,12 @@ int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb,
 		 * Unqueue the futex_q and determine which it was.
 		 */
 		plist_del(&q->list, &q->list.plist);
-		drop_futex_key_refs(&q->key);
 
+		/* Handle spurious wakeups gracefully */
+		ret = -EWOULDBLOCK;
 		if (timeout && !timeout->task)
 			ret = -ETIMEDOUT;
-		else
+		else if (signal_pending(current))
 			ret = -ERESTARTNOINTR;
 	}
 	return ret;