diff --git a/lib/aos/paging.c b/lib/aos/paging.c
index ebc0ac7..68d3d14 100644
--- a/lib/aos/paging.c
+++ b/lib/aos/paging.c
@@ -124,8 +124,12 @@ static void pt_exception_handler(enum exception_type type, int subtype,
             break;
         }
     }
-    if (vaddr_reg == NULL || vaddr_reg->free) {
-        debug_printf("[pt_exception_handler] page_addr = %x, base = %x, size = %x\n", page_addr, vaddr_reg->base, vaddr_reg->size);
+    if (vaddr_reg == NULL) {
+        debug_printf("[pt_exception_handler] page_addr = 0x%x\n", page_addr);
+        USER_PANIC("[pt_exception_handler][ERROR] Page fault ouside valid virtual address space");
+    }
+    if (vaddr_reg->free) {
+        debug_printf("[pt_exception_handler] page_addr = 0x%x, base = 0x%x, size = 0x%x\n", page_addr, vaddr_reg->base, vaddr_reg->size);
         USER_PANIC("[pt_exception_handler][ERROR] Page fault ouside allocated address space");
     }
     if (!vaddr_reg->heap) {