8159461: bigapps/Kitchensink/stressExitCode hits assert: Must be VMThread or JavaThread

Reviewed-by: fparain, simonis, dcubed

hotspot/src/os/aix/vm/os_aix.cpp

@@ -2686,7 +2686,8 @@ void os::hint_no_preempt() {}
 //      - sets target osthread state to continue
 //      - sends signal to end the sigsuspend loop in the SR_handler
 //
-//  Note that the SR_lock plays no role in this suspend/resume protocol.
+//  Note that the SR_lock plays no role in this suspend/resume protocol,
+//  but is checked for NULL in SR_handler as a thread termination indicator.
 //
 
 static void resume_clear_context(OSThread *osthread) {
@@ -2718,10 +2719,23 @@ static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
   // after sigsuspend.
   int old_errno = errno;
 
-  Thread* thread = Thread::current();
+  Thread* thread = Thread::current_or_null_safe();
-  OSThread* osthread = thread->osthread();
+  assert(thread != NULL, "Missing current thread in SR_handler");
+
+  // On some systems we have seen signal delivery get "stuck" until the signal
+  // mask is changed as part of thread termination. Check that the current thread
+  // has not already terminated (via SR_lock()) - else the following assertion
+  // will fail because the thread is no longer a JavaThread as the ~JavaThread
+  // destructor has completed.
+
+  if (thread->SR_lock() == NULL) {
+    return;
+  }
+
   assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
 
+  OSThread* osthread = thread->osthread();
+
   os::SuspendResume::State current = osthread->sr.state();
   if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
     suspend_save_context(osthread, siginfo, context);

hotspot/src/os/bsd/vm/os_bsd.cpp

@@ -2716,7 +2716,8 @@ void os::hint_no_preempt() {}
 //      - sets target osthread state to continue
 //      - sends signal to end the sigsuspend loop in the SR_handler
 //
-//  Note that the SR_lock plays no role in this suspend/resume protocol.
+//  Note that the SR_lock plays no role in this suspend/resume protocol,
+//  but is checked for NULL in SR_handler as a thread termination indicator.
 
 static void resume_clear_context(OSThread *osthread) {
   osthread->set_ucontext(NULL);
@@ -2746,10 +2747,23 @@ static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
   // after sigsuspend.
   int old_errno = errno;
 
-  Thread* thread = Thread::current();
+  Thread* thread = Thread::current_or_null_safe();
-  OSThread* osthread = thread->osthread();
+  assert(thread != NULL, "Missing current thread in SR_handler");
+
+  // On some systems we have seen signal delivery get "stuck" until the signal
+  // mask is changed as part of thread termination. Check that the current thread
+  // has not already terminated (via SR_lock()) - else the following assertion
+  // will fail because the thread is no longer a JavaThread as the ~JavaThread
+  // destructor has completed.
+
+  if (thread->SR_lock() == NULL) {
+    return;
+  }
+
   assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
 
+  OSThread* osthread = thread->osthread();
+
   os::SuspendResume::State current = osthread->sr.state();
   if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
     suspend_save_context(osthread, siginfo, context);

hotspot/src/os/linux/vm/os_linux.cpp

@@ -3971,7 +3971,8 @@ void os::hint_no_preempt() {}
 //      - sets target osthread state to continue
 //      - sends signal to end the sigsuspend loop in the SR_handler
 //
-//  Note that the SR_lock plays no role in this suspend/resume protocol.
+//  Note that the SR_lock plays no role in this suspend/resume protocol,
+//  but is checked for NULL in SR_handler as a thread termination indicator.
 
 static void resume_clear_context(OSThread *osthread) {
   osthread->set_ucontext(NULL);
@@ -4004,9 +4005,21 @@ static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
 
   Thread* thread = Thread::current_or_null_safe();
   assert(thread != NULL, "Missing current thread in SR_handler");
-  OSThread* osthread = thread->osthread();
+
+  // On some systems we have seen signal delivery get "stuck" until the signal
+  // mask is changed as part of thread termination. Check that the current thread
+  // has not already terminated (via SR_lock()) - else the following assertion
+  // will fail because the thread is no longer a JavaThread as the ~JavaThread
+  // destructor has completed.
+
+  if (thread->SR_lock() == NULL) {
+    return;
+  }
+
   assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
 
+  OSThread* osthread = thread->osthread();
+
   os::SuspendResume::State current = osthread->sr.state();
   if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
     suspend_save_context(osthread, siginfo, context);

hotspot/src/share/vm/runtime/thread.cpp

@@ -374,11 +374,14 @@ Thread::~Thread() {
   delete handle_area();
   delete metadata_handles();
 
+  // SR_handler uses this as a termination indicator -
+  // needs to happen before os::free_thread()
+  delete _SR_lock;
+  _SR_lock = NULL;
+
   // osthread() can be NULL, if creation of thread failed.
   if (osthread() != NULL) os::free_thread(osthread());
 
-  delete _SR_lock;
-
   // clear Thread::current if thread is deleting itself.
   // Needed to ensure JNI correctly detects non-attached threads.
   if (this == Thread::current()) {