From e4e8360eba33c1a656f57e39c717f045165f124e Mon Sep 17 00:00:00 2001
From: Ryan Macnak <rmacnak@google.com>
Date: Tue, 26 Nov 2024 22:53:09 +0000
Subject: [PATCH] [vm, isolates] Avoid three-way deadlock during isolate exit.

Running mutator
  holds safepoint operation scope starting old space GC
  waiting for old space tasks to reach 0

Concurrent marker
  holds old space tasks > 0
  waiting for isolates_list_ lock to interrupt for finalization

Exiting mutator
  holds isolates_list_ lock_ to unregister isolate
  waiting for safepoint to end TransitionVMToBlocked

Reorder isolate [un]registeration to not need safepoint transition to acquire the isolates_list_ lock.

TEST=ci
Bug: https://github.com/dart-lang/sdk/issues/59574
Change-Id: Ia98fabd654c880b253893a0598d2e26ed77f52da
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/397660
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
---
 runtime/vm/isolate.cc | 30 +++++++++++++-----------------
 runtime/vm/isolate.h  |  2 --
 runtime/vm/port.cc    |  4 ----
 3 files changed, 13 insertions(+), 23 deletions(-)

diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index 02361452fe2e..887d560d10e1 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -454,11 +454,6 @@ bool IsolateGroup::ContainsOnlyOneIsolate() {
   return isolate_count_ == 0 || isolate_count_ == 1;
 }
 
-void IsolateGroup::RunWithLockedGroup(std::function<void()> fun) {
-  SafepointWriteRwLocker ml(Thread::Current(), isolates_lock_.get());
-  fun();
-}
-
 void IsolateGroup::UnregisterIsolate(Isolate* isolate) {
   SafepointWriteRwLocker ml(Thread::Current(), isolates_lock_.get());
   isolates_.Remove(isolate);
@@ -1850,14 +1845,6 @@ Isolate* Isolate::InitIsolate(const char* name_prefix,
 #undef ISOLATE_METRIC_INIT
 #endif  // !defined(PRODUCT)
 
-  // First we ensure we enter the isolate. This will ensure we're participating
-  // in any safepointing requests from this point on. Other threads requesting a
-  // safepoint operation will therefore wait until we've stopped.
-  //
-  // Though the [result] isolate is still in a state where no memory has been
-  // allocated, which means it's safe to GC the isolate group until here.
-  Thread::EnterIsolate(result);
-
   // Setup the isolate message handler.
   result->message_handler_ = new IsolateMessageHandler(result);
 
@@ -1885,6 +1872,14 @@ Isolate* Isolate::InitIsolate(const char* name_prefix,
   // to vm-isolate objects, e.g. null)
   isolate_group->RegisterIsolate(result);
 
+  // Now we enter the isolate. This will ensure we're participating in any
+  // safepointing requests from this point on. Other threads requesting a
+  // safepoint operation will therefore wait until we've stopped.
+  //
+  // Though the [result] isolate is still in a state where no memory has been
+  // allocated, which means it's safe to GC the isolate group until here.
+  Thread::EnterIsolate(result);
+
   if (api_flags.is_service_isolate) {
     ASSERT(!ServiceIsolate::Exists());
     ServiceIsolate::SetServiceIsolate(result);
@@ -2619,14 +2614,15 @@ void Isolate::LowLevelCleanup(Isolate* isolate) {
   Dart_IsolateCleanupCallback cleanup = isolate->on_cleanup_callback();
   auto callback_data = isolate->init_callback_data_;
 
-  // From this point on the isolate is no longer visited by GC (which is ok,
-  // since we're just going to delete it anyway).
-  isolate_group->UnregisterIsolate(isolate);
-
   // From this point on the isolate doesn't participate in safepointing
   // requests anymore.
   ASSERT(!Thread::Current()->HasActiveState());
   Thread::ExitIsolate(/*isolate_shutdown=*/true);
+  ASSERT(Thread::Current() == nullptr);
+
+  // From this point on the isolate is no longer visited by GC (which is ok,
+  // since we're just going to delete it anyway).
+  isolate_group->UnregisterIsolate(isolate);
 
   // Now it's safe to delete the isolate.
   delete isolate;
diff --git a/runtime/vm/isolate.h b/runtime/vm/isolate.h
index a1d43d670a9b..8b7e1486b20e 100644
--- a/runtime/vm/isolate.h
+++ b/runtime/vm/isolate.h
@@ -327,8 +327,6 @@ class IsolateGroup : public IntrusiveDListEntry<IsolateGroup> {
 
   bool ContainsOnlyOneIsolate();
 
-  void RunWithLockedGroup(std::function<void()> fun);
-
   void ScheduleInterrupts(uword interrupt_bits);
 
   ThreadRegistry* thread_registry() const { return thread_registry_.get(); }
diff --git a/runtime/vm/port.cc b/runtime/vm/port.cc
index a6d037550f5c..547959ded280 100644
--- a/runtime/vm/port.cc
+++ b/runtime/vm/port.cc
@@ -59,10 +59,6 @@ Dart_Port PortMap::CreatePort(PortHandler* handler) {
     return ILLEGAL_PORT;
   }
 
-#if defined(DEBUG)
-  handler->CheckAccess();
-#endif
-
   const Dart_Port port = AllocatePort();
   if (auto ports = handler->ports(ml)) {
     ports->Insert(PortHandler::PortSetEntry{port});