--- a/tools/profiler/core/GeckoSampler.cpp
+++ b/tools/profiler/core/GeckoSampler.cpp
@@ -518,16 +518,17 @@ void GeckoSampler::StreamJSON(Spliceable
     aWriter.StartObjectProperty("meta");
       StreamMetaJSCustomObject(aWriter);
     aWriter.EndObject();
 
     // Data of TaskTracer doesn't belong in the circular buffer.
     if (TaskTracer()) {
       aWriter.StartObjectProperty("tasktracer");
       StreamTaskTracer(aWriter);
+      aWriter.EndObject();
     }
 
     // Lists the samples for each ThreadProfile
     aWriter.StartArrayProperty("threads");
     {
       SetPaused(true);
 
       {