diff --git a/kernel/src/syscall/mod.rs b/kernel/src/syscall/mod.rs
index aaf9b9f..046bd71 100644
--- a/kernel/src/syscall/mod.rs
+++ b/kernel/src/syscall/mod.rs
@@ -88,7 +88,7 @@ pub fn syscall(id: usize, args: [usize; 6], tf: &mut TrapFrame) -> isize {
         }
         SYS_GETPID => sys_getpid(),
         // 40
-        SYS_SENDFILE => sys_sendfile(args[0], args[1], args[3] as *mut usize, args[4]),
+        SYS_SENDFILE => sys_sendfile(args[0], args[1], args[2] as *mut usize, args[3]),
         SYS_SOCKET => sys_socket(args[0], args[1], args[2]),
         SYS_CONNECT => sys_connect(args[0], args[1] as *const SockAddr, args[2]),
         SYS_ACCEPT => sys_accept(args[0], args[1] as *mut SockAddr, args[2] as *mut u32),