diff --git a/kernel/src/memory.rs b/kernel/src/memory.rs
index c9e5f7d..dc9cd40 100644
--- a/kernel/src/memory.rs
+++ b/kernel/src/memory.rs
@@ -122,14 +122,20 @@ pub fn page_fault_handler(addr: usize) -> bool {
     info!("active page table token in pg fault is {:x?}", ActivePageTable::token());
     let id = memory_set_record().iter()
             .position(|x| unsafe{(*(x.clone() as *mut MemorySet)).get_page_table_mut().token() == ActivePageTable::token()});
-    info!("id got");
     let mut mmsets = memory_set_record();
-    info!("mmset got");
     match id {
         Some(targetid) => {
             info!("get id from memroy set recorder.");
             let mmset_ptr = mmsets.get(targetid);
-            let pt = unsafe { (*(mmset_ptr.unwrap().clone() as *mut MemorySet)).get_page_table_mut() };
+            // get current mmset
+            
+            let current_mmset = unsafe{&mut *(mmset_ptr.unwrap().clone() as *mut MemorySet)};
+            //check whether the vma is legal
+            if(current_mmset.find_area(addr).is_none()){
+                return false;
+            }
+
+            let pt = current_mmset.get_page_table_mut();
             info!("pt got!");
             if active_table_swap().page_fault_handler(pt as *mut InactivePageTable0, addr, false, || alloc_frame().unwrap()){
                 return true;
@@ -137,6 +143,10 @@ pub fn page_fault_handler(addr: usize) -> bool {
         },
         None => {
             info!("get pt from processor()");
+            if(process().get_memory_set_mut().find_area(addr).is_none()){
+                return false;
+            }
+
             let pt = process().get_memory_set_mut().get_page_table_mut();
             info!("pt got");
             if active_table_swap().page_fault_handler(pt as *mut InactivePageTable0, addr, true, || alloc_frame().unwrap()){