diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/futex.c | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index cf0c8e21d1ab..f59003b1d8f9 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -415,15 +415,15 @@ out_unlock: */ void exit_pi_state_list(struct task_struct *curr) { - struct futex_hash_bucket *hb; struct list_head *next, *head = &curr->pi_state_list; struct futex_pi_state *pi_state; + struct futex_hash_bucket *hb; union futex_key key; /* * We are a ZOMBIE and nobody can enqueue itself on * pi_state_list anymore, but we have to be careful - * versus waiters unqueueing themselfs + * versus waiters unqueueing themselves: */ spin_lock_irq(&curr->pi_lock); while (!list_empty(head)) { @@ -431,21 +431,24 @@ void exit_pi_state_list(struct task_struct *curr) 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); - hb = hash_futex(&key); spin_lock(&hb->lock); spin_lock_irq(&curr->pi_lock); + /* + * We dropped the pi-lock, so re-check whether this + * task still owns the PI-state: + */ if (head->next != next) { spin_unlock(&hb->lock); continue; } - list_del_init(&pi_state->list); - WARN_ON(pi_state->owner != curr); - + WARN_ON(list_empty(&pi_state->list)); + list_del_init(&pi_state->list); pi_state->owner = NULL; spin_unlock_irq(&curr->pi_lock); @@ -470,7 +473,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, struct futex_q *me) head = &hb->chain; list_for_each_entry_safe(this, next, head, list) { - if (match_futex (&this->key, &me->key)) { + if (match_futex(&this->key, &me->key)) { /* * Another waiter already exists - bump up * the refcount and return its pi_state: @@ -482,6 +485,8 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, struct futex_q *me) if (unlikely(!pi_state)) return -EINVAL; + WARN_ON(!atomic_read(&pi_state->refcount)); + atomic_inc(&pi_state->refcount); me->pi_state = pi_state; @@ -510,6 +515,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, struct futex_q *me) pi_state->key = me->key; spin_lock_irq(&p->pi_lock); + 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); @@ -584,9 +590,17 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this) if (curval != uval) return -EINVAL; - list_del_init(&pi_state->owner->pi_state_list); + 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); + + 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); + rt_mutex_unlock(&pi_state->pi_mutex); return 0; @@ -1236,6 +1250,7 @@ static int do_futex_lock_pi(u32 __user *uaddr, int detect, int trylock, /* Owner died? */ if (q.pi_state->owner != NULL) { spin_lock_irq(&q.pi_state->owner->pi_lock); + WARN_ON(list_empty(&q.pi_state->list)); list_del_init(&q.pi_state->list); spin_unlock_irq(&q.pi_state->owner->pi_lock); } else @@ -1244,6 +1259,7 @@ static int do_futex_lock_pi(u32 __user *uaddr, int detect, int trylock, q.pi_state->owner = current; spin_lock_irq(¤t->pi_lock); + WARN_ON(!list_empty(&q.pi_state->list)); list_add(&q.pi_state->list, ¤t->pi_state_list); spin_unlock_irq(¤t->pi_lock); |