--- a/js/src/vm/SavedStacks.cpp
+++ b/js/src/vm/SavedStacks.cpp
@@ -743,32 +743,27 @@ SavedStacks::chooseSamplingProbability(J
     allocationSamplingProbability = allocationTrackingDbg->allocationSamplingProbability;
 }
 
 SavedStacks::FrameState::FrameState(const FrameIter &iter)
     : principals(iter.compartment()->principals),
       name(iter.isNonEvalFunctionFrame() ? iter.functionDisplayAtom() : nullptr),
       location()
 {
-    if (principals)
-        JS_HoldPrincipals(principals);
 }
 
 SavedStacks::FrameState::FrameState(const FrameState &fs)
     : principals(fs.principals),
       name(fs.name),
       location(fs.location)
 {
-    if (principals)
-        JS_HoldPrincipals(principals);
 }
 
-SavedStacks::FrameState::~FrameState() {
-    if (principals)
-        JS_DropPrincipals(TlsPerThreadData.get()->runtimeFromMainThread(), principals);
+SavedStacks::FrameState::~FrameState()
+{
 }
 
 void
 SavedStacks::FrameState::trace(JSTracer *trc) {
     if (name)
         gc::MarkStringUnbarriered(trc, &name, "SavedStacks::FrameState::name");
     location.trace(trc);
 }

--- a/js/src/vm/SavedStacks.h
+++ b/js/src/vm/SavedStacks.h
@@ -228,16 +228,19 @@ class SavedStacks {
         FrameState() : principals(nullptr), name(nullptr), location() { }
         explicit FrameState(const FrameIter &iter);
         FrameState(const FrameState &fs);
 
         ~FrameState();
 
         void trace(JSTracer *trc);
 
+        // Note: we don't have to hold/drop principals, because we're
+        // only alive while the stack is being walked and during this
+        // time the principals are kept alive by the stack itself.
         JSPrincipals  *principals;
         JSAtom        *name;
         LocationValue location;
     };
 
     class MOZ_STACK_CLASS AutoFrameStateVector : public JS::CustomAutoRooter {
       public:
         explicit AutoFrameStateVector(JSContext *cx)