tests: posix: pthread: test for pthread descriptor leaks

Add a simple test to ensure that we can create and join a
single thread `CONFIG_MAX_PTHREAD_COUNT` * 2 times. If
there are leaks, then `pthread_create()` should
eventually return `EAGAIN`. If there are no leaks, then
the test should pass.

Fixes #47609

Signed-off-by: Christopher Friedt <[email protected]>
(cherry picked from commit d37350b)

Author: Christopher Friedt

tests/posix/common/src/main.c

@@ -21,6 +21,7 @@ extern void test_posix_pthread_create_negative(void);
 extern void test_posix_pthread_termination(void);
 extern void test_posix_multiple_threads_single_key(void);
 extern void test_posix_single_thread_multiple_keys(void);
+extern void test_pthread_descriptor_leak(void);
 extern void test_nanosleep_NULL_NULL(void);
 extern void test_nanosleep_NULL_notNULL(void);
 extern void test_nanosleep_notNULL_NULL(void);
@@ -45,6 +46,7 @@ void test_main(void)
 			ztest_unit_test(test_posix_pthread_termination),
 			ztest_unit_test(test_posix_multiple_threads_single_key),
 			ztest_unit_test(test_posix_single_thread_multiple_keys),
+			ztest_unit_test(test_pthread_descriptor_leak),
 			ztest_unit_test(test_posix_clock),
 			ztest_unit_test(test_posix_semaphore),
 			ztest_unit_test(test_posix_normal_mutex),

tests/posix/common/src/pthread.c

@@ -560,3 +560,20 @@ void test_posix_pthread_create_negative(void)
 	ret = pthread_create(&pthread1, &attr1, create_thread1, (void *)1);
 	zassert_equal(ret, EINVAL, "create thread with 0 size");
 }
+
+void test_pthread_descriptor_leak(void)
+{
+	void *unused;
+	pthread_t pthread1;
+	pthread_attr_t attr;
+
+	zassert_ok(pthread_attr_init(&attr), NULL);
+	zassert_ok(pthread_attr_setstack(&attr, &stack_e[0][0], STACKS), NULL);
+
+	/* If we are leaking descriptors, then this loop will never complete */
+	for (size_t i = 0; i < CONFIG_MAX_PTHREAD_COUNT * 2; ++i) {
+		zassert_ok(pthread_create(&pthread1, &attr, create_thread1, NULL),
+			   "unable to create thread %zu", i);
+		zassert_ok(pthread_join(pthread1, &unused), "unable to join thread %zu", i);
+	}
+}