perf_hooks: fix PerformanceObserver 'gc' crash

Signed-off-by: James M Snell <[email protected]>
Fixes: #38412

PR-URL: #38414
Reviewed-By: Michaël Zasso <[email protected]>
Reviewed-By: Antoine du Hamel <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Richard Lau <[email protected]>
Reviewed-By: Zijian Liu <[email protected]>

Author: jasnell

lib/internal/perf/observe.js

@@ -72,6 +72,8 @@ const kDeprecationMessage =
 const kTypeSingle = 0;
 const kTypeMultiple = 1;
 
+let gcTrackingInstalled = false;
+
 const kSupportedEntryTypes = ObjectFreeze([
   'function',
   'gc',
@@ -124,8 +126,11 @@ function maybeIncrementObserverCount(type) {
 
   if (observerType !== undefined) {
     observerCounts[observerType]++;
-    if (observerType === NODE_PERFORMANCE_ENTRY_TYPE_GC)
+    if (!gcTrackingInstalled &&
+        observerType === NODE_PERFORMANCE_ENTRY_TYPE_GC) {
       installGarbageCollectionTracking();
+      gcTrackingInstalled = true;
+    }
   }
 }
 

test/parallel/test-performanceobserver-gc.js

@@ -0,0 +1,17 @@
+'use strict';
+
+require('../common');
+
+// Verifies that setting up two observers to listen
+// to gc performance does not crash.
+
+const {
+  PerformanceObserver,
+} = require('perf_hooks');
+
+// We don't actually care if the callback is ever invoked in this test
+const obs = new PerformanceObserver(() => {});
+const obs2 = new PerformanceObserver(() => {});
+
+obs.observe({ type: 'gc' });
+obs2.observe({ type: 'gc' });