fix: obtain correct page table entry when performing eviction

src/userprog/exception.c

@@ -252,7 +252,7 @@ fetch_page (void *upage, bool write)
 {
   /* Check if the page is in the supplemental page table. That is, it is a page
      that is expected to be in memory. */
-  struct page_entry *page = page_get (upage);
+  struct page_entry *page = page_get (thread_current (), upage);
   if (page == NULL)
     return false;
 

src/userprog/syscall.c

@@ -462,7 +462,7 @@ syscall_mmap (int fd, void *addr)
      hold the entire file. */
   for (off_t ofs = 0; ofs < file_size; ofs += PGSIZE)
     {
-      if (page_get (addr + ofs) != NULL)
+      if (page_get (thread_current (), addr + ofs) != NULL)
         return MMAP_FAILURE;
     }