8373837: "assert(thread->is_VM_thread() || thread->is_Java_thread()) failed: Must be VMThread or JavaThread" on macosx-aarch64-26

Reviewed-by: fbredberg, coleenp

Author: David Holmes

src/hotspot/os/posix/signals_posix.cpp

@@ -1669,21 +1669,21 @@ static void SR_handler(int sig, siginfo_t* siginfo, void* context) {
 
   // 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 - else the following assertion
-  // will fail because the thread is no longer a JavaThread as the ~JavaThread
-  // destructor has completed.
-
+  // has not already terminated, else the osthread may already have been freed.
   if (thread->has_terminated()) {
     return;
   }
 
-  assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
-
   OSThread* osthread = thread->osthread();
 
   SuspendResume::State current = osthread->sr.state();
 
   if (current == SuspendResume::SR_SUSPEND_REQUEST) {
+    // Only check this on an active suspend request. It is possible to get a late delivered
+    // signal from a cancelled suspend request that hits after the JavaThread destructor
+    // completes, but before the Thread destructor causes `is_terminated()` to be true.
+    assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
+
     suspend_save_context(osthread, siginfo, context);
 
     // attempt to switch the state, we assume we had a SUSPEND_REQUEST