Merge pull request #3972 from DataDog/ivoanjo/prof-10656-add-provisional-error-checking

[PROF-10656] Add extra error checking to heap profiling function

Author: ivoanjo

ext/datadog_profiling_native_extension/heap_recorder.c

@@ -784,8 +784,20 @@ static void cleanup_heap_record_if_unused(heap_recorder *heap_recorder, heap_rec
 }
 
 static void on_committed_object_record_cleanup(heap_recorder *heap_recorder, object_record *record) {
+  // @ivoanjo: We've seen a segfault crash in the field in this function (October 2024) which we're still trying to investigate.
+  // (See PROF-10656 Datadog-internal for details). Just in case, I've sprinkled a bunch of NULL tests in this function for now.
+  // Once we figure out the issue we can get rid of them again.
+
+  if (heap_recorder == NULL) rb_raise(rb_eRuntimeError, "heap_recorder was NULL in on_committed_object_record_cleanup");
+  if (heap_recorder->heap_records == NULL) rb_raise(rb_eRuntimeError, "heap_recorder->heap_records was NULL in on_committed_object_record_cleanup");
+  if (record == NULL) rb_raise(rb_eRuntimeError, "record was NULL in on_committed_object_record_cleanup");
+
   // Starting with the associated heap record. There will now be one less tracked object pointing to it
   heap_record *heap_record = record->heap_record;
+
+  if (heap_record == NULL) rb_raise(rb_eRuntimeError, "heap_record was NULL in on_committed_object_record_cleanup");
+  if (heap_record->stack == NULL) rb_raise(rb_eRuntimeError, "heap_record->stack was NULL in on_committed_object_record_cleanup");
+
   heap_record->num_tracked_objects--;
 
   // One less object using this heap record, it may have become unused...