diff options
| -rw-r--r-- | kernel/locking/rtmutex_api.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c index 92b7d289a8af..5c9299aaabae 100644 --- a/kernel/locking/rtmutex_api.c +++ b/kernel/locking/rtmutex_api.c @@ -214,7 +214,19 @@ EXPORT_SYMBOL_GPL(__rt_mutex_init); void __sched rt_mutex_init_proxy_locked(struct rt_mutex_base *lock, struct task_struct *proxy_owner) { + static struct lock_class_key pi_futex_key; + __rt_mutex_base_init(lock); + /* + * On PREEMPT_RT the futex hashbucket spinlock becomes 'sleeping' + * and rtmutex based. That causes a lockdep false positive, because + * some of the futex functions invoke spin_unlock(&hb->lock) with + * the wait_lock of the rtmutex associated to the pi_futex held. + * spin_unlock() in turn takes wait_lock of the rtmutex on which + * the spinlock is based, which makes lockdep notice a lock + * recursion. Give the futex/rtmutex wait_lock a separate key. + */ + lockdep_set_class(&lock->wait_lock, &pi_futex_key); rt_mutex_set_owner(lock, proxy_owner); } |