diff --git a/js/public/ProfilingFrameIterator.h b/js/public/ProfilingFrameIterator.h
index 46946c3715..1f9d52d04b 100644
--- a/js/public/ProfilingFrameIterator.h
+++ b/js/public/ProfilingFrameIterator.h
@@ -54,8 +54,6 @@ class JS_PUBLIC_API(ProfilingFrameIterator)
     // activation (if any) comes around.
     void* savedPrevJitTop_;
 
-    JS::AutoCheckCannotGC nogc_;
-
     static const unsigned StorageSpace = 8 * sizeof(void*);
     mozilla::AlignedStorage<StorageSpace> storage_;
     js::wasm::ProfilingFrameIterator& wasmIter() {
@@ -139,7 +137,7 @@ class JS_PUBLIC_API(ProfilingFrameIterator)
     void iteratorConstruct();
     void iteratorDestroy();
     bool iteratorDone();
-};
+} JS_HAZ_GC_INVALIDATED;
 
 JS_FRIEND_API(bool)
 IsProfilingEnabledForContext(JSContext* cx);
diff --git a/js/src/gc/GCRuntime.h b/js/src/gc/GCRuntime.h
index cf2f7b036a..b961130bdf 100644
--- a/js/src/gc/GCRuntime.h
+++ b/js/src/gc/GCRuntime.h
@@ -714,13 +714,18 @@ class GCRuntime
 #endif // DEBUG
 
     bool isInsideUnsafeRegion() { return inUnsafeRegion != 0; }
-    void enterUnsafeRegion() { ++inUnsafeRegion; }
+    void enterUnsafeRegion() {
+        MOZ_ASSERT(CurrentThreadCanAccessRuntime(rt));
+        ++inUnsafeRegion;
+    }
     void leaveUnsafeRegion() {
+        MOZ_ASSERT(CurrentThreadCanAccessRuntime(rt));
         MOZ_ASSERT(inUnsafeRegion > 0);
         --inUnsafeRegion;
     }
 
     void verifyIsSafeToGC() {
+        MOZ_ASSERT(CurrentThreadCanAccessRuntime(rt));
         MOZ_DIAGNOSTIC_ASSERT(!isInsideUnsafeRegion(),
                               "[AutoAssertNoGC] possible GC in GC-unsafe region");
     }
diff --git a/js/src/vm/Stack.cpp b/js/src/vm/Stack.cpp
index b1bb8a753a..36fd998bd1 100644
--- a/js/src/vm/Stack.cpp
+++ b/js/src/vm/Stack.cpp
@@ -1739,8 +1739,7 @@ JS::ProfilingFrameIterator::ProfilingFrameIterator(JSContext* cx, const Register
   : rt_(cx),
     sampleBufferGen_(sampleBufferGen),
     activation_(nullptr),
-    savedPrevJitTop_(nullptr),
-    nogc_(cx)
+    savedPrevJitTop_(nullptr)
 {
     if (!cx->spsProfiler.enabled())
         MOZ_CRASH("ProfilingFrameIterator called when spsProfiler not enabled for runtime.");