diff --git a/src/thread/pthread_mutex_consistent.c b/src/thread/pthread_mutex_consistent.c
index 96b83b52..27c74e5b 100644
--- a/src/thread/pthread_mutex_consistent.c
+++ b/src/thread/pthread_mutex_consistent.c
@@ -1,10 +1,14 @@
 #include "pthread_impl.h"
+#include "atomic.h"
 
 int pthread_mutex_consistent(pthread_mutex_t *m)
 {
-	if (!(m->_m_type & 8)) return EINVAL;
-	if ((m->_m_lock & 0x7fffffff) != __pthread_self()->tid)
+	int old = m->_m_lock;
+	int own = old & 0x3fffffff;
+	if (!(m->_m_type & 4) || !own || !(old & 0x40000000))
+		return EINVAL;
+	if (own != __pthread_self()->tid)
 		return EPERM;
-	m->_m_type &= ~8U;
+	a_and(&m->_m_lock, ~0x40000000);
 	return 0;
 }
diff --git a/src/thread/pthread_mutex_timedlock.c b/src/thread/pthread_mutex_timedlock.c
index 9867f389..b95af251 100644
--- a/src/thread/pthread_mutex_timedlock.c
+++ b/src/thread/pthread_mutex_timedlock.c
@@ -16,10 +16,12 @@ int __pthread_mutex_timedlock(pthread_mutex_t *restrict m, const struct timespec
 	while (spins-- && m->_m_lock && !m->_m_waiters) a_spin();
 
 	while ((r=__pthread_mutex_trylock(m)) == EBUSY) {
-		if (!(r=m->_m_lock) || ((r&0x40000000) && (type&4)))
+		r = m->_m_lock;
+		int own = r & 0x3fffffff;
+		if (!own && (!r || (type&4)))
 			continue;
 		if ((type&3) == PTHREAD_MUTEX_ERRORCHECK
-		 && (r&0x7fffffff) == __pthread_self()->tid)
+		    && own == __pthread_self()->tid)
 			return EDEADLK;
 
 		a_inc(&m->_m_waiters);
diff --git a/src/thread/pthread_mutex_trylock.c b/src/thread/pthread_mutex_trylock.c
index 783ca0c4..3fe59127 100644
--- a/src/thread/pthread_mutex_trylock.c
+++ b/src/thread/pthread_mutex_trylock.c
@@ -8,14 +8,14 @@ int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
 	int tid = self->tid;
 
 	old = m->_m_lock;
-	own = old & 0x7fffffff;
+	own = old & 0x3fffffff;
 	if (own == tid && (type&3) == PTHREAD_MUTEX_RECURSIVE) {
 		if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
 		m->_m_count++;
 		return 0;
 	}
-	if (own == 0x7fffffff) return ENOTRECOVERABLE;
-	if (own && (!(own & 0x40000000) || !(type & 4))) return EBUSY;
+	if (own == 0x3fffffff) return ENOTRECOVERABLE;
+	if (own || (old && !(type & 4))) return EBUSY;
 
 	if (m->_m_type & 128) {
 		if (!self->robust_list.off) {
@@ -25,6 +25,7 @@ int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
 		if (m->_m_waiters) tid |= 0x80000000;
 		self->robust_list.pending = &m->_m_next;
 	}
+	tid |= old & 0x40000000;
 
 	if (a_cas(&m->_m_lock, old, tid) != old) {
 		self->robust_list.pending = 0;
@@ -39,9 +40,8 @@ int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
 	self->robust_list.head = &m->_m_next;
 	self->robust_list.pending = 0;
 
-	if (own) {
+	if (old) {
 		m->_m_count = 0;
-		m->_m_type |= 8;
 		return EOWNERDEAD;
 	}
 
diff --git a/src/thread/pthread_mutex_unlock.c b/src/thread/pthread_mutex_unlock.c
index 7dd00d27..ea9f54dd 100644
--- a/src/thread/pthread_mutex_unlock.c
+++ b/src/thread/pthread_mutex_unlock.c
@@ -7,13 +7,18 @@ int __pthread_mutex_unlock(pthread_mutex_t *m)
 	int cont;
 	int type = m->_m_type & 15;
 	int priv = (m->_m_type & 128) ^ 128;
+	int new = 0;
 
 	if (type != PTHREAD_MUTEX_NORMAL) {
 		self = __pthread_self();
-		if ((m->_m_lock&0x7fffffff) != self->tid)
+		int old = m->_m_lock;
+		int own = old & 0x3fffffff;
+		if (own != self->tid)
 			return EPERM;
 		if ((type&3) == PTHREAD_MUTEX_RECURSIVE && m->_m_count)
 			return m->_m_count--, 0;
+		if ((type&4) && (old&0x40000000))
+			new = 0x7fffffff;
 		if (!priv) {
 			self->robust_list.pending = &m->_m_next;
 			__vm_lock();
@@ -24,7 +29,7 @@ int __pthread_mutex_unlock(pthread_mutex_t *m)
 		if (next != &self->robust_list.head) *(volatile void *volatile *)
 			((char *)next - sizeof(void *)) = prev;
 	}
-	cont = a_swap(&m->_m_lock, (type & 8) ? 0x7fffffff : 0);
+	cont = a_swap(&m->_m_lock, new);
 	if (type != PTHREAD_MUTEX_NORMAL && !priv) {
 		self->robust_list.pending = 0;
 		__vm_unlock();