diff --git a/runtime/PRESUBMIT.py b/runtime/PRESUBMIT.py
index b20a5374945..bee8c74dbe6 100644
--- a/runtime/PRESUBMIT.py
+++ b/runtime/PRESUBMIT.py
@@ -19,7 +19,6 @@ USE_PYTHON3 = True
 BANNED_FUNCTIONS = [
     ['\\bmemcpy\\(', 'memcpy'],
     ['\\bpthread_detach\\(', 'pthread_detach'],
-    ['\\bdetach\\(', 'std::thread::detach'],
 ]
 
 
diff --git a/runtime/vm/dart_api_impl.cc b/runtime/vm/dart_api_impl.cc
index 142bda92faf..a7ad3513e4f 100644
--- a/runtime/vm/dart_api_impl.cc
+++ b/runtime/vm/dart_api_impl.cc
@@ -742,6 +742,7 @@ DART_EXPORT bool Dart_IsError(Dart_Handle handle) {
 DART_EXPORT void Dart_KillIsolate(Dart_Isolate handle) {
   Isolate* isolate = reinterpret_cast<Isolate*>(handle);
   CHECK_ISOLATE(isolate);
+  TransitionNativeToVM transition(Thread::Current());
   Isolate::KillIfExists(isolate, Isolate::kKillMsg);
 }
 
diff --git a/runtime/vm/dart_api_impl_test.cc b/runtime/vm/dart_api_impl_test.cc
index 6712acee2d5..fca41536284 100644
--- a/runtime/vm/dart_api_impl_test.cc
+++ b/runtime/vm/dart_api_impl_test.cc
@@ -2649,7 +2649,9 @@ static Dart_NativeFunction OptExternalByteDataNativeResolver(
 }
 
 TEST_CASE(DartAPI_OptimizedExternalByteDataAccess) {
+  TransitionNativeToVM transition1(thread);
   NoBackgroundCompilerScope no_background_compiler(thread);
+  TransitionVMToNative transition2(thread);
 
   const char* kScriptChars = R"(
 import 'dart:typed_data';
diff --git a/runtime/vm/lockers.cc b/runtime/vm/lockers.cc
index ed816904844..8c061ffffa2 100644
--- a/runtime/vm/lockers.cc
+++ b/runtime/vm/lockers.cc
@@ -112,6 +112,7 @@ bool SafepointRwLock::EnterRead() {
   //
   // Though if the lock was already acquired by this thread before entering a
   // safepoint, we do allow the nested acquire (which is a NOP).
+  ASSERT(thread == nullptr || thread->execution_state() == Thread::kThreadInVM);
   DEBUG_ASSERT(thread == nullptr || thread->CanAcquireSafepointLocks() ||
                IsCurrentThreadReader());
 
@@ -178,6 +179,7 @@ void SafepointRwLock::EnterWrite() {
   //
   // Though if the lock was already acquired by this thread before entering a
   // safepoint, we do allow the nested acquire (which is a NOP).
+  ASSERT(thread == nullptr || thread->execution_state() == Thread::kThreadInVM);
   DEBUG_ASSERT(thread == nullptr || thread->CanAcquireSafepointLocks() ||
                IsCurrentThreadWriter());
 
diff --git a/runtime/vm/object_test.cc b/runtime/vm/object_test.cc
index 6246f2a388d..a01b8314174 100644
--- a/runtime/vm/object_test.cc
+++ b/runtime/vm/object_test.cc
@@ -5811,7 +5811,6 @@ TEST_CASE(DartAPI_BreakpointLockRace) {
                                                  &done);
 
   while (!done) {
-    ReloadParticipationScope allow_reload(thread);
     {
       TransitionNativeToVM transition(thread);
       const String& name = String::Handle(String::New(TestCase::url()));
diff --git a/runtime/vm/thread.cc b/runtime/vm/thread.cc
index 68de665e252..a099665fad6 100644
--- a/runtime/vm/thread.cc
+++ b/runtime/vm/thread.cc
@@ -1477,6 +1477,9 @@ bool Thread::CanAcquireSafepointLocks() const {
   // Example: We own reload safepoint operation, load kernel, which allocates
   // symbols, where the symbol implementation acquires the symbol lock (we know
   // other mutators at reload safepoint do not hold symbol lock).
+  if (current_safepoint_level() == SafepointLevel::kGCAndDeoptAndReload) {
+    return false;
+  }
   return isolate_group()->safepoint_handler()->InnermostSafepointOperation(
              this) >= SafepointLevel::kGCAndDeoptAndReload;
 }