diff --git a/tests/kernel/mem_protect/mem_protect/src/kobject.c b/tests/kernel/mem_protect/mem_protect/src/kobject.c
index 5314e81af28..122184160d4 100644
--- a/tests/kernel/mem_protect/mem_protect/src/kobject.c
+++ b/tests/kernel/mem_protect/mem_protect/src/kobject.c
@@ -9,14 +9,14 @@
 
 /* Kernel objects */
 
-K_THREAD_STACK_DEFINE(child_stack, KOBJECT_STACK_SIZE);
+K_THREAD_STACK_DECLARE(child_stack, KOBJECT_STACK_SIZE);
 K_THREAD_STACK_DEFINE(extra_stack, KOBJECT_STACK_SIZE);
 
 K_SEM_DEFINE(kobject_sem, SEMAPHORE_INIT_COUNT, SEMAPHORE_MAX_COUNT);
 K_SEM_DEFINE(kobject_public_sem, SEMAPHORE_INIT_COUNT, SEMAPHORE_MAX_COUNT);
 K_MUTEX_DEFINE(kobject_mutex);
 
-struct k_thread child_thread;
+extern struct k_thread child_thread;
 struct k_thread extra_thread;
 
 struct k_sem *random_sem_type;
diff --git a/tests/kernel/mem_protect/mem_protect/src/mem_domain.c b/tests/kernel/mem_protect/mem_protect/src/mem_domain.c
index 5c4c6c1ce81..4ea5ad7ed1b 100644
--- a/tests/kernel/mem_protect/mem_protect/src/mem_domain.c
+++ b/tests/kernel/mem_protect/mem_protect/src/mem_domain.c
@@ -8,8 +8,8 @@
 #include <kernel_internal.h> /* For z_main_thread */
 #include <zephyr/sys/libc-hooks.h> /* for z_libc_partition */
 
-static struct k_thread child_thread;
-static K_THREAD_STACK_DEFINE(child_stack, 512 + CONFIG_TEST_EXTRA_STACK_SIZE);
+struct k_thread child_thread;
+K_THREAD_STACK_DEFINE(child_stack, KOBJECT_STACK_SIZE);
 
 /* Special memory domain for test case purposes */
 static struct k_mem_domain test_domain;