diff --git a/bindings/gumjs/gumquickprocess.c b/bindings/gumjs/gumquickprocess.c
index 595fba92f..9299d3eb9 100644
--- a/bindings/gumjs/gumquickprocess.c
+++ b/bindings/gumjs/gumquickprocess.c
@@ -654,7 +654,7 @@ GUMJS_DEFINE_FUNCTION (gumjs_process_run_on_thread)
   GumQuickScope scope = GUM_QUICK_SCOPE_INIT (core);
   GumThreadId thread_id;
   JSValue user_func;
-  GumQuickRunOnThreadContext context;
+  GumQuickRunOnThreadContext * context;
   gboolean run;
 
   if (!_gum_quick_args_parse (args, "ZF", &thread_id, &user_func))
@@ -662,14 +662,15 @@ GUMJS_DEFINE_FUNCTION (gumjs_process_run_on_thread)
 
   _gum_quick_scope_suspend (&scope);
 
-  context.core = core;
-  context.user_func = JS_DupValue (core->ctx, user_func);
+  context = g_slice_new (GumQuickRunOnThreadContext);
+  context->core = core;
+  context->user_func = JS_DupValue (core->ctx, user_func);
 
   if (self->stalker == NULL)
     self->stalker = gum_stalker_new ();
 
   run = gum_stalker_run_on_thread (self->stalker, thread_id,
-      gum_js_process_run_cb, &context);
+      gum_js_process_run_cb, context);
 
   _gum_quick_scope_resume (&scope);
   gum_quick_flush_stalker (self, &scope);
@@ -680,6 +681,7 @@ GUMJS_DEFINE_FUNCTION (gumjs_process_run_on_thread)
   return JS_UNDEFINED;
 
 error:
+  g_slice_free (GumQuickRunOnThreadContext, context);
   _gum_quick_throw_literal (ctx, "failed to run on thread");
   return JS_EXCEPTION;
 }
@@ -701,6 +703,8 @@ gum_js_process_run_cb (const GumCpuContext * cpu_context,
   JS_FreeValue (core->ctx, user_func);
 
   _gum_quick_scope_leave (&scope);
+
+  g_slice_free (GumQuickRunOnThreadContext, context);
 }
 
 static void
diff --git a/bindings/gumjs/gumv8process.cpp b/bindings/gumjs/gumv8process.cpp
index 54991b5fa..8a0ec0eff 100644
--- a/bindings/gumjs/gumv8process.cpp
+++ b/bindings/gumjs/gumv8process.cpp
@@ -67,7 +67,7 @@ struct GumV8FindModuleByNameContext
 struct GumV8RunOnThreadContext
 {
   GumV8Core * core;
-  Global<Function> user_func;
+  Global<Function> * user_func;
 };
 
 GUMJS_DECLARE_GETTER (gumjs_process_get_main_module)
@@ -536,8 +536,7 @@ GUMJS_DEFINE_FUNCTION (gumjs_process_run_on_thread)
 {
   GumThreadId thread_id;
   Local<Function> user_func;
-  GumV8RunOnThreadContext context;
-  gboolean run;
+  gboolean run;  
 
   auto isolate = core->isolate;
 
@@ -547,13 +546,14 @@ GUMJS_DEFINE_FUNCTION (gumjs_process_run_on_thread)
   if (module->stalker == NULL)
     module->stalker = gum_stalker_new ();
 
-  context.core = core;
-  context.user_func = Global<Function> (isolate, user_func);
+  auto context = g_slice_new (GumV8RunOnThreadContext);
+  context->core = core;
+  context->user_func = new Global<Function> (isolate, user_func);
 
   {
     ScriptUnlocker unlocker (core);
     run = gum_stalker_run_on_thread (module->stalker, thread_id,
-        gum_js_process_run_cb, &context);
+        gum_js_process_run_cb, context);
   }
 
   gum_v8_flush_stalker (module);
@@ -577,11 +577,15 @@ gum_js_process_run_cb (const GumCpuContext * cpu_context,
   ScriptScope scope (core->script);
 
   auto isolate = core->isolate;
-  auto user_func = Local<Function>::New (isolate, context->user_func);
+  auto user_func = Local<Function>::New (isolate, *context->user_func);
   auto ctx = isolate->GetCurrentContext ();
   auto recv = Undefined (isolate);
   auto result = user_func->Call (ctx, recv, 0, nullptr);
   (void) result;
+
+  delete context->user_func;
+
+  g_slice_free (GumV8RunOnThreadContext, context);
 }
 
 static void