8235962: os::current_thread_id() is not signal safe on macOS

Use mach_thread_self instead of pthread_mach_thread_np

Reviewed-by: dholmes, cjplummer

src/hotspot/os/bsd/osThread_bsd.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,6 +36,7 @@ void OSThread::pd_initialize() {
 #else
   _thread_id        = NULL;
 #endif
+  _unique_thread_id = 0;
   _pthread_id       = NULL;
   _siginfo          = NULL;
   _ucontext         = NULL;
@@ -49,6 +50,22 @@ void OSThread::pd_initialize() {
   assert(_startThread_lock !=NULL, "check");
 }
 
+// Additional thread_id used to correlate threads in SA
+void OSThread::set_unique_thread_id() {
+#ifdef __APPLE__
+  thread_identifier_info_data_t m_ident_info;
+  mach_msg_type_number_t count = THREAD_IDENTIFIER_INFO_COUNT;
+
+  mach_port_t mach_thread_port = mach_thread_self();
+  guarantee(mach_thread_port != 0, "just checking");
+  thread_info(mach_thread_port, THREAD_IDENTIFIER_INFO,
+              (thread_info_t) &m_ident_info, &count);
+  mach_port_deallocate(mach_task_self(), mach_thread_port);
+
+  _unique_thread_id = m_ident_info.thread_id;
+#endif
+}
+
 void OSThread::pd_destroy() {
   delete _startThread_lock;
 }

src/hotspot/os/bsd/osThread_bsd.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -82,9 +82,7 @@
     _pthread_id = tid;
   }
 
-  void set_unique_thread_id(uint64_t id) {
+  void set_unique_thread_id();
-    _unique_thread_id = id;
-  }
 
   // ***************************************************************
   // suspension support.

src/hotspot/os/bsd/os_bsd.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -634,19 +634,6 @@ extern "C" objc_registerThreadWithCollector_t objc_registerThreadWithCollectorFu
 objc_registerThreadWithCollector_t objc_registerThreadWithCollectorFunction = NULL;
 #endif
 
-#ifdef __APPLE__
-static uint64_t locate_unique_thread_id(mach_port_t mach_thread_port) {
-  // Additional thread_id used to correlate threads in SA
-  thread_identifier_info_data_t     m_ident_info;
-  mach_msg_type_number_t            count = THREAD_IDENTIFIER_INFO_COUNT;
-
-  thread_info(mach_thread_port, THREAD_IDENTIFIER_INFO,
-              (thread_info_t) &m_ident_info, &count);
-
-  return m_ident_info.thread_id;
-}
-#endif
-
 // Thread start routine for all newly created threads
 static void *thread_native_entry(Thread *thread) {
 
@@ -672,10 +659,10 @@ static void *thread_native_entry(Thread *thread) {
     os::current_thread_id(), (uintx) pthread_self());
 
 #ifdef __APPLE__
-  uint64_t unique_thread_id = locate_unique_thread_id(osthread->thread_id());
+  // Store unique OS X thread id used by SA
-  guarantee(unique_thread_id != 0, "unique thread id was not found");
+  osthread->set_unique_thread_id();
-  osthread->set_unique_thread_id(unique_thread_id);
 #endif
+
   // initialize signal mask for this thread
   os::Bsd::hotspot_sigmask(thread);
 
@@ -823,12 +810,12 @@ bool os::create_attached_thread(JavaThread* thread) {
 
   osthread->set_thread_id(os::Bsd::gettid());
 
-  // Store pthread info into the OSThread
 #ifdef __APPLE__
-  uint64_t unique_thread_id = locate_unique_thread_id(osthread->thread_id());
+  // Store unique OS X thread id used by SA
-  guarantee(unique_thread_id != 0, "just checking");
+  osthread->set_unique_thread_id();
-  osthread->set_unique_thread_id(unique_thread_id);
 #endif
+
+  // Store pthread info into the OSThread
   osthread->set_pthread_id(::pthread_self());
 
   // initialize floating point control register
@@ -1101,11 +1088,10 @@ pid_t os::Bsd::gettid() {
   int retval = -1;
 
 #ifdef __APPLE__ // XNU kernel
-  // despite the fact mach port is actually not a thread id use it
+  mach_port_t port = mach_thread_self();
-  // instead of syscall(SYS_thread_selfid) as it certainly fits to u4
+  guarantee(MACH_PORT_VALID(port), "just checking");
-  retval = ::pthread_mach_thread_np(::pthread_self());
+  mach_port_deallocate(mach_task_self(), port);
-  guarantee(retval != 0, "just checking");
+  return (pid_t)port;
-  return retval;
 
 #else
   #ifdef __FreeBSD__
@@ -1128,7 +1114,7 @@ pid_t os::Bsd::gettid() {
 
 intx os::current_thread_id() {
 #ifdef __APPLE__
-  return (intx)::pthread_mach_thread_np(::pthread_self());
+  return (intx)os::Bsd::gettid();
 #else
   return (intx)::pthread_self();
 #endif