diff --git a/samples/livepatch/livepatch-shadow-fix1.c b/samples/livepatch/livepatch-shadow-fix1.c
index e89ca45..918ce17 100644
--- a/samples/livepatch/livepatch-shadow-fix1.c
+++ b/samples/livepatch/livepatch-shadow-fix1.c
@@ -52,17 +52,21 @@
  */
 static int shadow_leak_ctor(void *obj, void *shadow_data, void *ctor_data)
 {
-	void **shadow_leak = shadow_data;
-	void *leak = ctor_data;
+	int **shadow_leak = shadow_data;
+	int **leak = ctor_data;
 
-	*shadow_leak = leak;
+	if (!ctor_data)
+		return -EINVAL;
+
+	*shadow_leak = *leak;
 	return 0;
 }
 
 static struct dummy *livepatch_fix1_dummy_alloc(void)
 {
 	struct dummy *d;
-	void *leak;
+	int *leak;
+	int **shadow_leak;
 
 	d = kzalloc(sizeof(*d), GFP_KERNEL);
 	if (!d)
@@ -76,25 +80,34 @@
 	 * variable.  A patched dummy_free routine can later fetch this
 	 * pointer to handle resource release.
 	 */
-	leak = kzalloc(sizeof(int), GFP_KERNEL);
-	if (!leak) {
-		kfree(d);
-		return NULL;
-	}
+	leak = kzalloc(sizeof(*leak), GFP_KERNEL);
+	if (!leak)
+		goto err_leak;
 
-	klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL,
-			 shadow_leak_ctor, leak);
+	shadow_leak = klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL,
+				       shadow_leak_ctor, &leak);
+	if (!shadow_leak) {
+		pr_err("%s: failed to allocate shadow variable for the leaking pointer: dummy @ %p, leak @ %p\n",
+		       __func__, d, leak);
+		goto err_shadow;
+	}
 
 	pr_info("%s: dummy @ %p, expires @ %lx\n",
 		__func__, d, d->jiffies_expire);
 
 	return d;
+
+err_shadow:
+	kfree(leak);
+err_leak:
+	kfree(d);
+	return NULL;
 }
 
 static void livepatch_fix1_dummy_leak_dtor(void *obj, void *shadow_data)
 {
 	void *d = obj;
-	void **shadow_leak = shadow_data;
+	int **shadow_leak = shadow_data;
 
 	kfree(*shadow_leak);
 	pr_info("%s: dummy @ %p, prevented leak @ %p\n",
@@ -103,7 +116,7 @@
 
 static void livepatch_fix1_dummy_free(struct dummy *d)
 {
-	void **shadow_leak;
+	int **shadow_leak;
 
 	/*
 	 * Patch: fetch the saved SV_LEAK shadow variable, detach and