diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index f87d138e9672..759ff419fe61 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -92,15 +92,19 @@ static bool init_stack_slab(void **prealloc)
 		return true;
 	if (stack_slabs[depot_index] == NULL) {
 		stack_slabs[depot_index] = *prealloc;
+		*prealloc = NULL;
 	} else {
-		stack_slabs[depot_index + 1] = *prealloc;
+		/* If this is the last depot slab, do not touch the next one. */
+		if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) {
+			stack_slabs[depot_index + 1] = *prealloc;
+			*prealloc = NULL;
+		}
 		/*
 		 * This smp_store_release pairs with smp_load_acquire() from
 		 * |next_slab_inited| above and in depot_save_stack().
 		 */
 		smp_store_release(&next_slab_inited, 1);
 	}
-	*prealloc = NULL;
 	return true;
 }