--- a/xpcom/threads/BackgroundHangMonitor.cpp
+++ b/xpcom/threads/BackgroundHangMonitor.cpp
@@ -355,16 +355,23 @@ BackgroundHangThread::~BackgroundHangThr
 }
 
 Telemetry::HangHistogram&
 BackgroundHangThread::ReportHang(PRIntervalTime aHangTime)
 {
   // Recovered from a hang; called on the monitor thread
   // mManager->mLock IS locked
 
+  // Remove unwanted "js::RunScript" frame from the stack
+  for (const char** f = &mHangStack.back(); f >= mHangStack.begin(); f--) {
+    if (!mHangStack.IsInBuffer(*f) && !strcmp(*f, "js::RunScript")) {
+      mHangStack.erase(f);
+    }
+  }
+
   Telemetry::HangHistogram newHistogram(Move(mHangStack));
   for (Telemetry::HangHistogram* oldHistogram = mStats.mHangs.begin();
        oldHistogram != mStats.mHangs.end(); oldHistogram++) {
     if (newHistogram == *oldHistogram) {
       // New histogram matches old one
       oldHistogram->Add(aHangTime);
       return *oldHistogram;
     }

--- a/xpcom/threads/ThreadStackHelper.cpp
+++ b/xpcom/threads/ThreadStackHelper.cpp
@@ -668,20 +668,18 @@ ThreadStackHelper::FillStackBuffer()
       continue;
     }
 #ifdef MOZ_THREADSTACKHELPER_NATIVE
     if (mContextToFill) {
       mContextToFill->mStackEnd = entry->stackAddress();
     }
 #endif
     const char* const label = entry->label();
-    if (mStackToFill->IsSameAsEntry(prevLabel, label) ||
-        !strcmp(label, "js::RunScript")) {
+    if (mStackToFill->IsSameAsEntry(prevLabel, label)) {
       // Avoid duplicate labels to save space in the stack.
-      // Avoid js::RunScript labels because we save actual JS frames above.
       continue;
     }
     mStackToFill->infallibleAppend(label);
     prevLabel = label;
   }
 
   // end != entry if we exited early due to not enough reserved frames.
   // Expand the number of reserved frames for next time.