diff --git a/src/runtime/cpuprof.go b/src/runtime/cpuprof.go
index fb841a9f3d..e00dcb1bbd 100644
--- a/src/runtime/cpuprof.go
+++ b/src/runtime/cpuprof.go
@@ -160,6 +160,7 @@ func (p *cpuProfile) addExtra() {
 			funcPC(_ExternalCode) + sys.PCQuantum,
 		}
 		cpuprof.log.write(nil, 0, hdr[:], lostStk[:])
+		p.lostExtra = 0
 	}
 }