diff --git a/src/syscall/syscall_freebsd.go b/src/syscall/syscall_freebsd.go
index eecae8de30d..eb7208f5cc5 100644
--- a/src/syscall/syscall_freebsd.go
+++ b/src/syscall/syscall_freebsd.go
@@ -267,7 +267,7 @@ func Fstatfs(fd int, st *Statfs_t) (err error) {
 
 func Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) {
 	if supportsABI(_ino64First) {
-		if unsafe.Sizeof(*basep) == 8 {
+		if basep == nil || unsafe.Sizeof(*basep) == 8 {
 			return getdirentries_freebsd12(fd, buf, (*uint64)(unsafe.Pointer(basep)))
 		}
 		// The freebsd12 syscall needs a 64-bit base. On 32-bit machines