From 6b1b0e9d45eb56f88398e2a6bca0d90c03112eaa Mon Sep 17 00:00:00 2001
From: Andrei Pangin <apangin@openjdk.org>
Date: Tue, 2 Apr 2024 04:30:26 +0000
Subject: [PATCH] 8329103: assert(!thread->in_asgct()) failed during multi-mode
 profiling

Reviewed-by: dholmes, sspitsyn
---
 src/hotspot/share/runtime/thread.hpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/hotspot/share/runtime/thread.hpp b/src/hotspot/share/runtime/thread.hpp
index 7461876f378..32f7b7fa8ec 100644
--- a/src/hotspot/share/runtime/thread.hpp
+++ b/src/hotspot/share/runtime/thread.hpp
@@ -657,15 +657,17 @@ protected:
 class ThreadInAsgct {
  private:
   Thread* _thread;
+  bool _saved_in_asgct;
  public:
   ThreadInAsgct(Thread* thread) : _thread(thread) {
     assert(thread != nullptr, "invariant");
-    assert(!thread->in_asgct(), "invariant");
+    // Allow AsyncGetCallTrace to be reentrant - save the previous state.
+    _saved_in_asgct = thread->in_asgct();
     thread->set_in_asgct(true);
   }
   ~ThreadInAsgct() {
     assert(_thread->in_asgct(), "invariant");
-    _thread->set_in_asgct(false);
+    _thread->set_in_asgct(_saved_in_asgct);
   }
 };