Modified the code in pgfault

kernel/src/memory.rs

@@ -113,17 +113,16 @@ 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()});
-    let mut mmsets = memory_set_record();
     /*LAB3 EXERCISE 1: YOUR STUDENT NUMBER
     * handle the frame deallocated
     */
     match id {
         Some(targetid) => {
             info!("get id from memroy set recorder.");
-            let mmset_ptr = mmsets.get(targetid);
+            let mmset_ptr = memory_set_record().get(targetid).expect("fail to get mmset_ptr").clone();
             // get current mmset
 
-            let current_mmset = unsafe{&mut *(mmset_ptr.expect("fail to get mmset_ptr").clone() as *mut MemorySet)};
+            let current_mmset = unsafe{&mut *(mmset_ptr as *mut MemorySet)};
             //check whether the vma is legal
             if current_mmset.find_area(addr).is_none(){
                 return false;