diff --git a/src/cmd/link/internal/ld/fallocate_test.go b/src/cmd/link/internal/ld/fallocate_test.go
index a064bea23d0..51f5fcdd9fc 100644
--- a/src/cmd/link/internal/ld/fallocate_test.go
+++ b/src/cmd/link/internal/ld/fallocate_test.go
@@ -28,6 +28,21 @@ func TestFallocate(t *testing.T) {
 	}
 	defer out.Close()
 
+	// Try fallocate first.
+	for {
+		err = out.fallocate(1 << 10)
+		if err == syscall.EOPNOTSUPP { // The underlying file system may not support fallocate
+			t.Skip("fallocate is not supported")
+		}
+		if err == syscall.EINTR {
+			continue // try again
+		}
+		if err != nil {
+			t.Fatalf("fallocate failed: %v", err)
+		}
+		break
+	}
+
 	// Mmap 1 MiB initially, and grow to 2 and 3 MiB.
 	// Check if the file size and disk usage is expected.
 	for _, sz := range []int64{1 << 20, 2 << 20, 3 << 20} {
diff --git a/src/cmd/link/internal/ld/outbuf_darwin.go b/src/cmd/link/internal/ld/outbuf_darwin.go
index 9a74ba875e2..d7e3372230b 100644
--- a/src/cmd/link/internal/ld/outbuf_darwin.go
+++ b/src/cmd/link/internal/ld/outbuf_darwin.go
@@ -14,7 +14,10 @@ func (out *OutBuf) fallocate(size uint64) error {
 	if err != nil {
 		return err
 	}
-	cursize := uint64(stat.Size())
+	// F_PEOFPOSMODE allocates from the end of the file, so we want the size difference.
+	// Apparently, it uses the end of the allocation, instead of the logical end of the
+	// the file.
+	cursize := uint64(stat.Sys().(*syscall.Stat_t).Blocks * 512) // allocated size
 	if size <= cursize {
 		return nil
 	}
@@ -23,7 +26,7 @@ func (out *OutBuf) fallocate(size uint64) error {
 		Flags:   syscall.F_ALLOCATEALL,
 		Posmode: syscall.F_PEOFPOSMODE,
 		Offset:  0,
-		Length:  int64(size - cursize), // F_PEOFPOSMODE allocates from the end of the file, so we want the size difference here
+		Length:  int64(size - cursize),
 	}
 
 	_, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(out.f.Fd()), syscall.F_PREALLOCATE, uintptr(unsafe.Pointer(store)))