diff --git a/js/src/jit/AsmJS.cpp b/js/src/jit/AsmJS.cpp
index 266fc85028e..0ceb7b4cef4 100644
--- a/js/src/jit/AsmJS.cpp
+++ b/js/src/jit/AsmJS.cpp
@@ -1276,6 +1276,8 @@ class MOZ_STACK_CLASS ModuleCompiler
     }
 
     bool failName(ParseNode *pn, const char *fmt, PropertyName *name) {
+        // This function is invoked without the caller properly rooting its locals.
+        gc::AutoSuppressGC suppress(name->runtimeFromMainThread());
         JSAutoByteString bytes;
         if (AtomToPrintableString(cx_, name, &bytes))
             failf(pn, fmt, bytes.ptr());
diff --git a/js/src/jsgc.cpp b/js/src/jsgc.cpp
index c03c06db796..eaf52494124 100644
--- a/js/src/jsgc.cpp
+++ b/js/src/jsgc.cpp
@@ -5150,6 +5150,12 @@ AutoMaybeTouchDeadZones::~AutoMaybeTouchDeadZones()
     runtime->gcManipulatingDeadZones = manipulatingDeadZones;
 }
 
+AutoSuppressGC::AutoSuppressGC(JSRuntime *rt)
+  : suppressGC_(rt->mainThread.suppressGC)
+{
+    suppressGC_++;
+}
+
 AutoSuppressGC::AutoSuppressGC(ExclusiveContext *cx)
   : suppressGC_(cx->perThreadData->suppressGC)
 {
diff --git a/js/src/jsgc.h b/js/src/jsgc.h
index e38b603d12e..de9921f0c85 100644
--- a/js/src/jsgc.h
+++ b/js/src/jsgc.h
@@ -1400,6 +1400,7 @@ class AutoSuppressGC
     int32_t &suppressGC_;
 
   public:
+    AutoSuppressGC(JSRuntime *rt);
     AutoSuppressGC(ExclusiveContext *cx);
     AutoSuppressGC(JSCompartment *comp);