diff --git a/src/cmd/internal/buildid/buildid_test.go b/src/cmd/internal/buildid/buildid_test.go
index e832f9987e..4895a49e11 100644
--- a/src/cmd/internal/buildid/buildid_test.go
+++ b/src/cmd/internal/buildid/buildid_test.go
@@ -177,3 +177,11 @@ func TestExcludedReader(t *testing.T) {
 		}
 	}
 }
+
+func TestEmptyID(t *testing.T) {
+	r := strings.NewReader("aha!")
+	matches, hash, err := FindAndHash(r, "", 1000)
+	if matches != nil || hash != ([32]byte{}) || err == nil || !strings.Contains(err.Error(), "no id") {
+		t.Errorf("FindAndHash: want nil, [32]byte{}, no id specified, got %v, %v, %v", matches, hash, err)
+	}
+}
diff --git a/src/cmd/internal/buildid/rewrite.go b/src/cmd/internal/buildid/rewrite.go
index a7928959c4..8814950db0 100644
--- a/src/cmd/internal/buildid/rewrite.go
+++ b/src/cmd/internal/buildid/rewrite.go
@@ -22,6 +22,9 @@ func FindAndHash(r io.Reader, id string, bufSize int) (matches []int64, hash [32
 	if bufSize == 0 {
 		bufSize = 31 * 1024 // bufSize+little will likely fit in 32 kB
 	}
+	if len(id) == 0 {
+		return nil, [32]byte{}, fmt.Errorf("buildid.FindAndHash: no id specified")
+	}
 	if len(id) > bufSize {
 		return nil, [32]byte{}, fmt.Errorf("buildid.FindAndHash: buffer too small")
 	}