diff --git a/kernel/futex.c b/kernel/futex.c
index 4711f80b85..c65456c481 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -102,7 +102,7 @@ dword_t sys_futex(addr_t uaddr, dword_t op, dword_t val, addr_t timeout_or_val2,
         STRACE("!FUTEX_PRIVATE ");
     }
     struct timespec timeout = {0};
-    if ((op & (FUTEX_WAIT_)) > 0) {
+    if ((op & FUTEX_CMD_MASK_) == FUTEX_WAIT_ && timeout_or_val2) {
         struct timespec_ timeout_;
         if (user_get(timeout_or_val2, timeout_))
             return _EFAULT;