Feature: Test for Bad Thread Join Argument

In this commit, I have introduced fault injection tests for joining a
thread using a bad pointer to get the return value of the terminating
thread. Note that this test is not enabled by default, because the
kernel may not support this checking in some targets.

src/test/kthread.c

@@ -37,6 +37,7 @@
 /**@{*/
 #define UTEST_KTHREAD_BAD_START 0 /**< Test bad thread start?    */
 #define UTEST_KTHREAD_BAD_ARG   0 /**< Test bad thread argument? */
+#define UTEST_KTHREAD_BAD_JOIN  0 /**< Test bad thread join?     */
 /**@}*/
 
 /**
@@ -121,6 +122,14 @@ void test_fault_kthread_create(void)
 	test_assert(kthread_create(&tid[0], task, NULL) == 0);
 	test_assert(kthread_join(2, NULL) < 0);
 	test_assert(kthread_join(tid[0], NULL) == 0);
+
+	/* Join with bad return value. */
+#if (defined(UTEST_KTHREAD_BAD_JOIN) && (UTEST_KTHREAD_BAD_JOIN == 1))
+	test_assert(kthread_create(&tid[0], task, NULL) == 0);
+	test_assert(kthread_join(tid[0], (void *)(KBASE_VIRT)) < 0);
+	test_assert(kthread_join(tid[0], (void *)(UBASE_VIRT - PAGE_SIZE)) < 0);
+	test_assert(kthread_join(tid[0], NULL) == 0);
+#endif
 }
 
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