tests/kernel/threads: Correct essential thread abort test

Thread abort of essential threads had a buglet where the panic would
be signaled but, if caught by k_sys_fatal_error_handler(), the thread
would not actually be aborted.  This test wasn't validating that the
thread was actually dead (in fac, it RELIED on the thread to signal a
semaphore after its "abort"!).

Make sure it's dead and that the panic is caught.  Also add a case for
aborting _current which is a separate code path that needs coverage.

Signed-off-by: Andy Ross <[email protected]>

Author: andyross

tests/kernel/threads/thread_apis/src/test_essential_thread.c

@@ -67,8 +67,6 @@ void k_sys_fatal_error_handler(unsigned int reason,
 	ARG_UNUSED(reason);
 
 	fatal_error_signaled = true;
-
-	z_thread_essential_clear(_current);
 }
 
 static void abort_thread_entry(void *p1, void *p2, void *p3)
@@ -77,16 +75,19 @@ static void abort_thread_entry(void *p1, void *p2, void *p3)
 	ARG_UNUSED(p2);
 	ARG_UNUSED(p3);
 
-	z_thread_essential_set(_current);
-
 	if (z_is_thread_essential(_current)) {
-		k_busy_wait(100);
+		k_msleep(200);
 	} else {
 		zassert_unreachable("The thread is not set as essential");
 	}
 
-	k_sem_give(&sync_sem);
-	k_sleep(K_FOREVER);
+	zassert_true(false, "Should not reach this line");
+}
+
+static void abort_thread_self(void *p1, void *p2, void *p3)
+{
+	k_thread_abort(k_current_get());
+	zassert_true(false, "Should not reach this line");
 }
 
 /**
@@ -102,13 +103,22 @@ static void abort_thread_entry(void *p1, void *p2, void *p3)
 
 ZTEST(threads_lifecycle, test_essential_thread_abort)
 {
-	k_tid_t tid = k_thread_create(&kthread_thread1, kthread_stack, STACKSIZE,
-				      abort_thread_entry,
-				      NULL, NULL, NULL, K_PRIO_PREEMPT(0), 0,
-				      K_NO_WAIT);
+	fatal_error_signaled = false;
+	k_thread_create(&kthread_thread1, kthread_stack, STACKSIZE,
+			abort_thread_entry,
+			NULL, NULL, NULL, K_PRIO_PREEMPT(0), K_ESSENTIAL,
+			K_NO_WAIT);
+
+	k_msleep(100);
+	k_thread_abort(&kthread_thread1);
+	zassert_true(fatal_error_signaled, "fatal error was not signaled");
 
-	k_sem_take(&sync_sem, K_FOREVER);
-	k_thread_abort(tid);
+	fatal_error_signaled = false;
+	k_thread_create(&kthread_thread1, kthread_stack, STACKSIZE,
+			abort_thread_self,
+			NULL, NULL, NULL, K_PRIO_PREEMPT(0), K_ESSENTIAL,
+			K_NO_WAIT);
 
+	k_msleep(100);
 	zassert_true(fatal_error_signaled, "fatal error was not signaled");
 }