1 files changed, 9 insertions, 4 deletions
diff --git a/src/runtime/runtime.go b/src/runtime/runtime.go
index 0822d0e805..15119cf5df 100644
--- a/src/runtime/runtime.go
+++ b/src/runtime/runtime.go
@@ -101,12 +101,17 @@ func (g *godebugInc) IncNonDefault() {
 		if newInc == nil {
 			return
 		}
-		// If other goroutines are racing here, no big deal. One will win,
-		// and all the inc functions will be using the same underlying
-		// *godebug.Setting.
 		inc = new(func())
 		*inc = (*newInc)(g.name)
-		g.inc.Store(inc)
+		if raceenabled {
+			racereleasemerge(unsafe.Pointer(&g.inc))
+		}
+		if !g.inc.CompareAndSwap(nil, inc) {
+			inc = g.inc.Load()
+		}
+	}
+	if raceenabled {
+		raceacquire(unsafe.Pointer(&g.inc))
 	}
 	(*inc)()
 }