diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index f7768d8d03dd1dc9e8c5c26c974d9a86a8176571..0189f02844f1e7af23f25e273b6ff321fdbceb57 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -102,7 +102,7 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
 	}
 	size += __pthread_tsd_size;
 	map = mmap(0, size, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0);
-	if (!map) return EAGAIN;
+	if (map == MAP_FAILED) return EAGAIN;
 	if (guard) mprotect(map, guard, PROT_NONE);
 
 	tsd = map + size - __pthread_tsd_size;