ref(profiling): unref timer (#12340)

Tentative fix for
#12169

I did not generate a core dump, but by looking at the crash, it seemed
like it the segfault was happening after the bindings were required and
the code after the require statement had already ran, which hints at an
issue with the measurement collection loop.

This is a small change, but it ensures that the reference to the timer
is not maintained and can be properly collected, as well as adds a
missing nullptr check.

Author: JonasBa

packages/profiling-node/bindings/cpu_profiler.cc

@@ -76,7 +76,8 @@ class MeasurementsTicker {
   MeasurementsTicker(uv_loop_t *loop)
       : period_ms(100), isolate(v8::Isolate::GetCurrent()) {
     uv_timer_init(loop, &timer);
-    timer.data = this;
+    uv_handle_set_data(reinterpret_cast<uv_handle_t *>(&timer), this);
+    uv_unref(reinterpret_cast<uv_handle_t *>(&timer));
   }
 
   static void ticker(uv_timer_t *);
@@ -196,6 +197,10 @@ void MeasurementsTicker::cpu_callback() {
 };
 
 void MeasurementsTicker::ticker(uv_timer_t *handle) {
+  if (handle == nullptr) {
+    return;
+  }
+
   MeasurementsTicker *self = static_cast<MeasurementsTicker *>(handle->data);
   self->heap_callback();
   self->cpu_callback();
@@ -323,18 +328,6 @@ void SentryProfile::Start(Profiler *profiler) {
   status = ProfileStatus::kStarted;
 }
 
-static void CleanupSentryProfile(Profiler *profiler,
-                                 SentryProfile *sentry_profile,
-                                 const std::string &profile_id) {
-  if (sentry_profile == nullptr) {
-    return;
-  }
-
-  sentry_profile->Stop(profiler);
-  profiler->active_profiles.erase(profile_id);
-  delete sentry_profile;
-};
-
 v8::CpuProfile *SentryProfile::Stop(Profiler *profiler) {
   // Stop the CPU Profiler
   v8::CpuProfile *profile = profiler->cpu_profiler->StopProfiling(
@@ -376,6 +369,18 @@ const uint16_t &SentryProfile::cpu_usage_write_index() const {
   return cpu_write_index;
 };
 
+static void CleanupSentryProfile(Profiler *profiler,
+                                 SentryProfile *sentry_profile,
+                                 const std::string &profile_id) {
+  if (sentry_profile == nullptr) {
+    return;
+  }
+
+  sentry_profile->Stop(profiler);
+  profiler->active_profiles.erase(profile_id);
+  delete sentry_profile;
+};
+
 #ifdef _WIN32
 static const char kPlatformSeparator = '\\';
 static const char kWinDiskPrefix = ':';
@@ -1049,6 +1054,7 @@ void FreeAddonData(napi_env env, void *data, void *hint) {
 
   if (profiler->cpu_profiler != nullptr) {
     profiler->cpu_profiler->Dispose();
+    profiler->cpu_profiler = nullptr;
   }
 
   delete profiler;