diff --git a/internal/weight/nm/measure.go b/internal/weight/nm/measure.go
index 80315e4..0517a21 100644
--- a/internal/weight/nm/measure.go
+++ b/internal/weight/nm/measure.go
@@ -78,7 +78,7 @@ func parseLine(s string) (*Sym, error) {
 	infoField := ""
 
 	isSymType := func(s string) bool {
-		return len(s) == 1 && unicode.IsLetter(rune(s[0]))
+		return len(s) == 1 && (unicode.IsLetter(rune(s[0]))  || s[0] == '_')
 	}
 
 	switch {
diff --git a/internal/weight/nm/measure_test.go b/internal/weight/nm/measure_test.go
index 76eab86..b28fa2a 100644
--- a/internal/weight/nm/measure_test.go
+++ b/internal/weight/nm/measure_test.go
@@ -16,6 +16,7 @@ var validLines = []string{
 	`1091ca0        192 T type:.eq.[2]interface {}`,
 	`1060160        160 T type:.eq.[2]runtime.Frame`,
 	`1001fa0        256 T type:.eq.[6]internal/cpu.option`,
+	`       0          0 _ go.go`,
 }
 
 func TestParseLine(t *testing.T) {