diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c
index 9698259..0ad540f 100644
--- a/src/malloc/malloc.c
+++ b/src/malloc/malloc.c
@@ -6,6 +6,7 @@
 #include <errno.h>
 #include <sys/mman.h>
 #include "libc.h"
+#include "lock.h"
 #include "atomic.h"
 #include "pthread_impl.h"
 #include "malloc_impl.h"
@@ -26,12 +27,18 @@ int __malloc_replaced;
 
 static inline void lock(volatile int *lk)
 {
+	if (!libc.threads_minus_1 || !a_cas(lk, 0, INT_MIN + 1)) return;
+	LOCK(lk);
+	return;
 	if (libc.threads_minus_1)
 		while(a_swap(lk, 1)) __wait(lk, lk+1, 1, 1);
 }
 
 static inline void unlock(volatile int *lk)
 {
+	if (lk[0] < 0 && a_fetch_add(lk, -(INT_MIN + 1)) != (INT_MIN + 1))
+		__wake(lk, 1, 1);
+	return;
 	if (lk[0]) {
 		a_store(lk, 0);
 		if (lk[1]) __wake(lk, 1, 1);