fix crash if pthread_mutex_unlock is called without ever locking

[musl] / src / thread / pthread_mutex_unlock.c

diff --git a/src/thread/pthread_mutex_unlock.c b/src/thread/pthread_mutex_unlock.c
index 67aa7ba..6950872 100644 (file)
--- a/src/thread/pthread_mutex_unlock.c
+++ b/src/thread/pthread_mutex_unlock.c
@@ -3,22 +3,29 @@
 int pthread_mutex_unlock(pthread_mutex_t *m)
 {
        pthread_t self;
+       int waiters = m->_m_waiters;
+       int cont;
 
        if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
-               self = __pthread_self();
+               if (!m->_m_lock)
+                       return EPERM;
+               self = pthread_self();
                if ((m->_m_lock&0x1fffffff) != self->tid)
-                       return EPERM;
-               if ((m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE && --m->_m_count)
-                       return 0;
+                       return EPERM;
+               if ((m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE && m->_m_count)
+                       return m->_m_count--, 0;
                if (m->_m_type >= 4) {
                        self->robust_list.pending = &m->_m_next;
                        *(void **)m->_m_prev = m->_m_next;
                        if (m->_m_next) ((void **)m->_m_next)[-1] = m->_m_prev;
+                       cont = a_swap(&m->_m_lock, 0);
+                       self->robust_list.pending = 0;
+                       goto wake;
                }
        }
-
-       m->_m_lock = 0;
-       if (m->_m_waiters) __wake(&m->_m_lock, 1, 0);
-       if (m->_m_type >= 4) self->robust_list.pending = 0;
+       cont = a_swap(&m->_m_lock, 0);
+wake:
+       if (waiters || cont<0)
+               __wake(&m->_m_lock, 1, 0);
        return 0;
 }