posix: add pthread specific data deallocation test

This commit adds test to assert that thread specific data is deallocated
on thread termination.

Signed-off-by: Jakub Michalski <jmichalski@antmicro.com>

tests/posix/common/prj.conf

@@ -9,6 +9,8 @@ CONFIG_THREAD_NAME=y
 CONFIG_DYNAMIC_THREAD=y
 CONFIG_THREAD_STACK_INFO=y
 CONFIG_DYNAMIC_THREAD_POOL_SIZE=6
+CONFIG_POSIX_THREAD_KEYS_MAX=512
+CONFIG_TEST_EXTRA_STACK_SIZE=4096
 
 # for fnmatch()
 CONFIG_POSIX_C_LIB_EXT=y

tests/posix/common/src/key.c

@@ -144,6 +144,44 @@ ZTEST(key, test_correct_key_is_deleted)
 	}
 }
 
+static void *setspecific_thread(void *count)
+{
+	int value = 42;
+	int *alloc_count = count;
+
+	while (1) {
+		pthread_key_t key;
+
+		zassert_ok(pthread_key_create(&key, NULL), "failed to create key");
+		if (pthread_setspecific(key, &value) == ENOMEM) {
+			break;
+		};
+		*alloc_count += 1;
+	}
+
+	return NULL;
+}
+
+ZTEST(key, test_thread_specific_data_deallocation)
+{
+	pthread_t thread;
+	static int alloc_count_t0;
+	static int alloc_count_t1;
+
+	zassert_ok(pthread_create(&thread, NULL, setspecific_thread, &alloc_count_t0),
+		"attempt to create thread failed");
+	zassert_ok(pthread_join(thread, NULL), "failed to join thread");
+	printk("first thread allocated %d keys", alloc_count_t0);
+
+	zassert_ok(pthread_create(&thread, NULL, setspecific_thread, &alloc_count_t1),
+		"attempt to create thread failed");
+	zassert_ok(pthread_join(thread, NULL), "failed to join thread");
+	printk("second thread allocated %d keys", alloc_count_t1);
+
+	zassert_equal(alloc_count_t0, alloc_count_t1,
+		"failed to deallocate thread specific data");
+}
+
 static void before(void *arg)
 {
 	ARG_UNUSED(arg);

tests/posix/common/testcase.yaml

@@ -67,6 +67,8 @@ tests:
       - CONFIG_DYNAMIC_THREAD=y
       - CONFIG_THREAD_STACK_INFO=y
       - CONFIG_HEAP_MEM_POOL_SIZE=16384
+      - CONFIG_POSIX_THREAD_KEYS_MAX=2048
+      - CONFIG_TEST_EXTRA_STACK_SIZE=16384
   portability.posix.common.static_stack:
     extra_configs:
       - CONFIG_DYNAMIC_THREAD=n