diff --git a/monoio-rustls/src/safe_io.rs b/monoio-rustls/src/safe_io.rs
index 11b196a..b6b33bf 100644
--- a/monoio-rustls/src/safe_io.rs
+++ b/monoio-rustls/src/safe_io.rs
@@ -104,6 +104,11 @@ impl Default for SafeRead {
 
 impl SafeRead {
     pub(crate) async fn do_io<IO: AsyncReadRent>(&mut self, mut io: IO) -> io::Result<usize> {
+        if self.buffer.is_none() {
+            // if called do_io after the time async read/write had been cancelled, 
+            // buffer will be none, so we return Other error.
+            return Err(io::ErrorKind::Other.into());
+        }
         // if there are some data inside the buffer, just return.
         let buffer = self.buffer.as_ref().expect("buffer ref expected");
         if !buffer.is_empty() {
@@ -134,6 +139,11 @@ impl SafeRead {
 
 impl io::Read for SafeRead {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        if self.buffer.is_none() {
+            // if called read after the time async read/write had been cancelled, 
+            // buffer will be none, so we return Other error.
+            return Err(io::ErrorKind::Other.into());
+        }
         // if buffer is empty, return WoundBlock.
         let buffer = self.buffer.as_mut().expect("buffer mut expected");
         if buffer.is_empty() {
@@ -187,6 +197,11 @@ impl Default for SafeWrite {
 
 impl SafeWrite {
     pub(crate) async fn do_io<IO: AsyncWriteRent>(&mut self, mut io: IO) -> io::Result<usize> {
+        if self.buffer.is_none() {
+            // if called do_io after the time async read/write had been cancelled, 
+            // buffer will be none, so we return Other error.
+            return Err(io::ErrorKind::Other.into());
+        }
         // if the buffer is empty, just return.
         let buffer = self.buffer.as_ref().expect("buffer ref expected");
         if buffer.is_empty() {
@@ -213,6 +228,11 @@ impl SafeWrite {
 
 impl io::Write for SafeWrite {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buffer.is_none() {
+            // if called write after the time async read/write had been cancelled, 
+            // buffer will be none, so we return Other error.
+            return Err(io::ErrorKind::Other.into());
+        }
         // if there is too much data inside the buffer, return WoundBlock
         let buffer = self.buffer.as_mut().expect("buffer mut expected");
         if !matches!(self.status, WriteStatus::Ok) {
@@ -233,6 +253,11 @@ impl io::Write for SafeWrite {
     }
 
     fn flush(&mut self) -> io::Result<()> {
+        if self.buffer.is_none() {
+            // if called flush after the time async read/write had been cancelled, 
+            // buffer will be none, so we return Other error.
+            return Err(io::ErrorKind::Other.into());
+        }
         let buffer = self.buffer.as_mut().expect("buffer mut expected");
         if !matches!(self.status, WriteStatus::Ok) {
             match std::mem::replace(&mut self.status, WriteStatus::Ok) {