diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index be0178c9f22..b31d0a4ed80 100644
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -1112,7 +1112,7 @@ type toolchain interface {
 type noToolchain struct{}
 
 func noCompiler() error {
-	log.Fatal("unknown compiler %q", buildContext.Compiler)
+	log.Fatalf("unknown compiler %q", buildContext.Compiler)
 	return nil
 }
 
diff --git a/src/cmd/godoc/godoc.go b/src/cmd/godoc/godoc.go
index b290e31a893..01b609b0552 100644
--- a/src/cmd/godoc/godoc.go
+++ b/src/cmd/godoc/godoc.go
@@ -88,7 +88,7 @@ func initHandlers() {
 	for _, p := range filepath.SplitList(*pkgPath) {
 		_, elem := filepath.Split(p)
 		if elem == "" {
-			log.Fatal("invalid -path argument: %q has no final element", p)
+			log.Fatalf("invalid -path argument: %q has no final element", p)
 		}
 		fs.Bind("/src/pkg/"+elem, OS(p), "/", bindReplace)
 	}
diff --git a/src/pkg/net/unicast_test.go b/src/pkg/net/unicast_test.go
index 8bfe2796e0f..f164f34825f 100644
--- a/src/pkg/net/unicast_test.go
+++ b/src/pkg/net/unicast_test.go
@@ -545,7 +545,7 @@ func TestProhibitionaryDialArgs(t *testing.T) {
 	for _, tt := range prohibitionaryDialArgTests {
 		_, err = Dial(tt.net, tt.addr+":"+port)
 		if err == nil {
-			t.Fatal("Dial(%q, %q) should fail", tt.net, tt.addr)
+			t.Fatalf("Dial(%q, %q) should fail", tt.net, tt.addr)
 		}
 	}
 }