From 7cb2e31f4b5d4bdd4b5174efb2793e10b6bb3d00 Mon Sep 17 00:00:00 2001
From: Yuval Tassa <tassa@google.com>
Date: Thu, 20 Nov 2025 09:02:58 -0800
Subject: [PATCH] Annotate GlobalModel for LSAN

PiperOrigin-RevId: 834784936
Change-Id: I9381a062956df6cd7724402b72c2d2a2d8c49998
---
 src/xml/xml_api.cc | 46 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/xml/xml_api.cc b/src/xml/xml_api.cc
index b9678eae..43ccf803 100644
--- a/src/xml/xml_api.cc
+++ b/src/xml/xml_api.cc
@@ -27,10 +27,9 @@
 #include <type_traits>
 
 #include <mujoco/mjmodel.h>
-#include "engine/engine_io.h"
 #include <mujoco/mjspec.h>
+#include "engine/engine_io.h"
 #include "user/user_resource.h"
-#include "user/user_vfs.h"
 #include "xml/xml.h"
 #include "xml/xml_native_reader.h"
 #include "xml/xml_util.h"
@@ -39,6 +38,31 @@
 #include <pxr/usd/usd/stage.h>
 #endif
 
+
+// leak sanitizer support: default to no-op
+#define MJ_LSAN_IGNORE(ptr) ((void)(ptr))
+
+// on Linux with GCC/Clang and LSAN available
+#if (defined(__GNUC__) || defined(__clang__)) && !defined(__APPLE__) && !defined(_WIN32)
+#ifdef __has_include
+#if __has_include(<sanitizer/lsan_interface.h>)
+
+// define weak lsan_ignore_object symbol
+#include <sanitizer/lsan_interface.h>
+extern "C" void __lsan_ignore_object(const void*) __attribute__((weak));
+namespace {
+inline void lsan_ignore(const void* ptr) { if (__lsan_ignore_object) __lsan_ignore_object(ptr); }
+}  // namespace
+
+// redefine MJ_LSAN_IGNORE to use lsan_ignore
+#undef MJ_LSAN_IGNORE
+#define MJ_LSAN_IGNORE(ptr) lsan_ignore(ptr)
+
+#endif  // LSAN API available
+#endif  // __has_include
+#endif  // Linux with GCC/Clang
+
+
 //---------------------------------- Globals -------------------------------------------------------
 
 namespace {
@@ -53,6 +77,12 @@ class GlobalModel {
   std::optional<std::string> ToXML(const mjModel* m, char* error,
                                       int error_sz);
 
+  // mark this GlobalModel and its allocations as intentional (not leaks)
+  void AnnotateLSan() {
+    MJ_LSAN_IGNORE(this);
+    MJ_LSAN_IGNORE(mutex_);
+  }
+
  private:
   // using raw pointers as GlobalModel needs to be trivially destructible
   std::mutex* mutex_ = new std::mutex();
@@ -79,6 +109,11 @@ void GlobalModel::Set(mjSpec* spec) {
     mj_deleteSpec(spec_);
   }
   spec_ = spec;
+
+  // mark the spec as an intentional long-lived allocation
+  if (spec_) {
+    MJ_LSAN_IGNORE(spec_);
+  }
 }
 
 
@@ -86,6 +121,13 @@ void GlobalModel::Set(mjSpec* spec) {
 GlobalModel& GetGlobalModel() {
   static GlobalModel global_model;
 
+  // mark the GlobalModel singleton and its mutex as intentional allocations
+  static bool lsan_annotated = false;
+  if (!lsan_annotated) {
+    global_model.AnnotateLSan();
+    lsan_annotated = true;
+  }
+
   // global variables must be trivially destructible
   static_assert(std::is_trivially_destructible_v<decltype(global_model)>);
   return global_model;