From 98403b75df0a0737bdf082231f38c5c0019fe4c9 Mon Sep 17 00:00:00 2001
From: Doug Simon <dnsimon@openjdk.org>
Date: Wed, 23 Oct 2024 20:01:14 +0000
Subject: [PATCH] 8342854: [JVMCI] Block secondary thread reporting a JVMCI
 fatal error

Reviewed-by: never
---
 src/hotspot/share/jvmci/jvmci.cpp | 19 +++++++++----------
 src/hotspot/share/jvmci/jvmci.hpp |  4 ++--
 2 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/src/hotspot/share/jvmci/jvmci.cpp b/src/hotspot/share/jvmci/jvmci.cpp
index 447792b6fca..48d286e91ed 100644
--- a/src/hotspot/share/jvmci/jvmci.cpp
+++ b/src/hotspot/share/jvmci/jvmci.cpp
@@ -50,7 +50,7 @@ char* JVMCI::_shared_library_path = nullptr;
 volatile bool JVMCI::_in_shutdown = false;
 StringEventLog* JVMCI::_events = nullptr;
 StringEventLog* JVMCI::_verbose_events = nullptr;
-volatile intx JVMCI::_fatal_log_init_thread = -1;
+volatile intx JVMCI::_first_error_tid = -1;
 volatile int JVMCI::_fatal_log_fd = -1;
 const char* JVMCI::_fatal_log_filename = nullptr;
 
@@ -354,7 +354,7 @@ void JVMCI::fatal_log(const char* buf, size_t count) {
   intx current_thread_id = os::current_thread_id();
   intx invalid_id = -1;
   int log_fd;
-  if (_fatal_log_init_thread == invalid_id && Atomic::cmpxchg(&_fatal_log_init_thread, invalid_id, current_thread_id) == invalid_id) {
+  if (_first_error_tid == invalid_id && Atomic::cmpxchg(&_first_error_tid, invalid_id, current_thread_id) == invalid_id) {
     if (ErrorFileToStdout) {
       log_fd = 1;
     } else if (ErrorFileToStderr) {
@@ -375,14 +375,13 @@ void JVMCI::fatal_log(const char* buf, size_t count) {
       }
     }
     _fatal_log_fd = log_fd;
-  } else {
-    // Another thread won the race to initialize the stream. Give it time
-    // to complete initialization. VM locks cannot be used as the current
-    // thread might not be attached to the VM (e.g. a native thread started
-    // within libjvmci).
-    while (_fatal_log_fd == -1) {
-      os::naked_short_sleep(50);
-    }
+  } else if (_first_error_tid != current_thread_id) {
+    // This is not the first thread reporting a libjvmci error
+    tty->print_cr("[thread " INTX_FORMAT " also had an error in the JVMCI native library]",
+                    current_thread_id);
+
+    // Fatal error reporting is single threaded so just block this thread.
+    os::infinite_sleep();
   }
   fdStream log(_fatal_log_fd);
   log.write(buf, count);
diff --git a/src/hotspot/share/jvmci/jvmci.hpp b/src/hotspot/share/jvmci/jvmci.hpp
index 1e9fa08898f..4c1d828004e 100644
--- a/src/hotspot/share/jvmci/jvmci.hpp
+++ b/src/hotspot/share/jvmci/jvmci.hpp
@@ -117,8 +117,8 @@ class JVMCI : public AllStatic {
   // The path of the file underlying _fatal_log_fd if it is a normal file.
   static const char* _fatal_log_filename;
 
-  // Native thread id of thread that will initialize _fatal_log_fd.
-  static volatile intx _fatal_log_init_thread;
+  // Thread id of the first thread reporting a libjvmci error.
+  static volatile intx _first_error_tid;
 
   // JVMCI event log (shows up in hs_err crash logs).
   static StringEventLog* _events;