diff --git a/compio-driver/src/sys/fusion/mod.rs b/compio-driver/src/sys/fusion/mod.rs
index bfebddae..197f5b4a 100644
--- a/compio-driver/src/sys/fusion/mod.rs
+++ b/compio-driver/src/sys/fusion/mod.rs
@@ -72,7 +72,7 @@ impl super::Extra {
 /// Fused [`OpCode`]
 ///
 /// This trait encapsulates both operation for `io-uring` and `polling`
-pub trait OpCode: PollOpCode + IourOpCode {}
+pub unsafe trait OpCode: PollOpCode + IourOpCode {}
 
 impl<T: PollOpCode + IourOpCode + ?Sized> OpCode for T {}
 
diff --git a/compio-driver/src/sys/iocp/mod.rs b/compio-driver/src/sys/iocp/mod.rs
index 205181f9..4271a90b 100644
--- a/compio-driver/src/sys/iocp/mod.rs
+++ b/compio-driver/src/sys/iocp/mod.rs
@@ -274,7 +274,7 @@ pub enum OpType {
 }
 
 /// Abstraction of IOCP operations.
-pub trait OpCode {
+pub unsafe trait OpCode {
     /// Determines that the operation is really overlapped defined by Windows
     /// API. If not, the driver will try to operate it in another thread.
     fn op_type(&self) -> OpType {
diff --git a/compio-driver/src/sys/iocp/op.rs b/compio-driver/src/sys/iocp/op.rs
index 84a15aae..33f43c44 100644
--- a/compio-driver/src/sys/iocp/op.rs
+++ b/compio-driver/src/sys/iocp/op.rs
@@ -154,7 +154,7 @@ impl<
     }
 }
 
-impl OpCode for CloseFile {
+unsafe impl OpCode for CloseFile {
     fn op_type(&self) -> OpType {
         OpType::Blocking
     }
@@ -309,7 +309,7 @@ impl<S: AsFd> OpCode for ShutdownSocket<S> {
     }
 }
 
-impl OpCode for CloseSocket {
+unsafe impl OpCode for CloseSocket {
     fn op_type(&self) -> OpType {
         OpType::Blocking
     }
diff --git a/compio-driver/src/sys/iour/mod.rs b/compio-driver/src/sys/iour/mod.rs
index ff0c0568..1732ea05 100644
--- a/compio-driver/src/sys/iour/mod.rs
+++ b/compio-driver/src/sys/iour/mod.rs
@@ -107,7 +107,7 @@ impl From<io_uring::squeue::Entry128> for OpEntry {
 }
 
 /// Abstraction of io-uring operations.
-pub trait OpCode {
+pub unsafe trait OpCode {
     /// Create submission entry.
     fn create_entry(self: Pin<&mut Self>) -> OpEntry;
 
diff --git a/compio-driver/src/sys/iour/op.rs b/compio-driver/src/sys/iour/op.rs
index 3865b173..4225b829 100644
--- a/compio-driver/src/sys/iour/op.rs
+++ b/compio-driver/src/sys/iour/op.rs
@@ -61,7 +61,7 @@ impl<
     }
 }
 
-impl OpCode for OpenFile {
+unsafe impl OpCode for OpenFile {
     fn create_entry(self: Pin<&mut Self>) -> OpEntry {
         opcode::OpenAt::new(Fd(libc::AT_FDCWD), self.path.as_ptr())
             .flags(self.flags | libc::O_CLOEXEC)
@@ -71,7 +71,7 @@ impl OpCode for OpenFile {
     }
 }
 
-impl OpCode for CloseFile {
+unsafe impl OpCode for CloseFile {
     fn create_entry(self: Pin<&mut Self>) -> OpEntry {
         opcode::Close::new(Fd(self.fd.as_fd().as_raw_fd()))
             .build()
@@ -155,7 +155,7 @@ impl PathStat {
     }
 }
 
-impl OpCode for PathStat {
+unsafe impl OpCode for PathStat {
     fn create_entry(mut self: Pin<&mut Self>) -> OpEntry {
         let mut flags = libc::AT_EMPTY_PATH;
         if !self.follow_symlink {
@@ -309,7 +309,7 @@ impl<S: AsFd> OpCode for Sync<S> {
     }
 }
 
-impl OpCode for Unlink {
+unsafe impl OpCode for Unlink {
     fn create_entry(self: Pin<&mut Self>) -> OpEntry {
         opcode::UnlinkAt::new(Fd(libc::AT_FDCWD), self.path.as_ptr())
             .flags(if self.dir { libc::AT_REMOVEDIR } else { 0 })
@@ -318,7 +318,7 @@ impl OpCode for Unlink {
     }
 }
 
-impl OpCode for CreateDir {
+unsafe impl OpCode for CreateDir {
     fn create_entry(self: Pin<&mut Self>) -> OpEntry {
         opcode::MkDirAt::new(Fd(libc::AT_FDCWD), self.path.as_ptr())
             .mode(self.mode)
@@ -327,7 +327,7 @@ impl OpCode for CreateDir {
     }
 }
 
-impl OpCode for Rename {
+unsafe impl OpCode for Rename {
     fn create_entry(self: Pin<&mut Self>) -> OpEntry {
         opcode::RenameAt::new(
             Fd(libc::AT_FDCWD),
@@ -340,7 +340,7 @@ impl OpCode for Rename {
     }
 }
 
-impl OpCode for Symlink {
+unsafe impl OpCode for Symlink {
     fn create_entry(self: Pin<&mut Self>) -> OpEntry {
         opcode::SymlinkAt::new(
             Fd(libc::AT_FDCWD),
@@ -352,7 +352,7 @@ impl OpCode for Symlink {
     }
 }
 
-impl OpCode for HardLink {
+unsafe impl OpCode for HardLink {
     fn create_entry(self: Pin<&mut Self>) -> OpEntry {
         opcode::LinkAt::new(
             Fd(libc::AT_FDCWD),
@@ -365,7 +365,7 @@ impl OpCode for HardLink {
     }
 }
 
-impl OpCode for CreateSocket {
+unsafe impl OpCode for CreateSocket {
     fn create_entry(self: Pin<&mut Self>) -> OpEntry {
         if super::is_op_supported(opcode::Socket::CODE) {
             opcode::Socket::new(
@@ -397,7 +397,7 @@ impl<S: AsFd> OpCode for ShutdownSocket<S> {
     }
 }
 
-impl OpCode for CloseSocket {
+unsafe impl OpCode for CloseSocket {
     fn create_entry(self: Pin<&mut Self>) -> OpEntry {
         opcode::Close::new(Fd(self.fd.as_fd().as_raw_fd()))
             .build()
diff --git a/compio-driver/src/sys/poll/mod.rs b/compio-driver/src/sys/poll/mod.rs
index e0a5f823..5612b62c 100644
--- a/compio-driver/src/sys/poll/mod.rs
+++ b/compio-driver/src/sys/poll/mod.rs
@@ -48,7 +48,7 @@ impl From<WaitArg> for Track {
 /// `Some(OpType::Fd)` with same fds as the `WaitArg`s. Similarly, if
 /// `pre_submit` returns `Decision::Aio`, `op_type` must return
 /// `Some(OpType::Aio)` with the correct `aiocb` pointer.
-pub trait OpCode {
+pub unsafe trait OpCode {
     /// Perform the operation before submit, and return [`Decision`] to
     /// indicate whether submitting the operation to polling is required.
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision>;
diff --git a/compio-driver/src/sys/poll/op.rs b/compio-driver/src/sys/poll/op.rs
index c1f6617a..f710b025 100644
--- a/compio-driver/src/sys/poll/op.rs
+++ b/compio-driver/src/sys/poll/op.rs
@@ -68,7 +68,7 @@ impl<
     }
 }
 
-impl OpCode for OpenFile {
+unsafe impl OpCode for OpenFile {
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision> {
         Ok(Decision::Blocking)
     }
@@ -82,7 +82,7 @@ impl OpCode for OpenFile {
     }
 }
 
-impl OpCode for CloseFile {
+unsafe impl OpCode for CloseFile {
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision> {
         Ok(Decision::Blocking)
     }
@@ -176,7 +176,7 @@ impl PathStat {
     }
 }
 
-impl OpCode for PathStat {
+unsafe impl OpCode for PathStat {
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision> {
         Ok(Decision::Blocking)
     }
@@ -526,7 +526,7 @@ impl<S: AsFd> OpCode for Sync<S> {
     }
 }
 
-impl OpCode for Unlink {
+unsafe impl OpCode for Unlink {
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision> {
         Ok(Decision::Blocking)
     }
@@ -541,7 +541,7 @@ impl OpCode for Unlink {
     }
 }
 
-impl OpCode for CreateDir {
+unsafe impl OpCode for CreateDir {
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision> {
         Ok(Decision::Blocking)
     }
@@ -552,7 +552,7 @@ impl OpCode for CreateDir {
     }
 }
 
-impl OpCode for Rename {
+unsafe impl OpCode for Rename {
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision> {
         Ok(Decision::Blocking)
     }
@@ -563,7 +563,7 @@ impl OpCode for Rename {
     }
 }
 
-impl OpCode for Symlink {
+unsafe impl OpCode for Symlink {
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision> {
         Ok(Decision::Blocking)
     }
@@ -574,7 +574,7 @@ impl OpCode for Symlink {
     }
 }
 
-impl OpCode for HardLink {
+unsafe impl OpCode for HardLink {
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision> {
         Ok(Decision::Blocking)
     }
@@ -645,7 +645,7 @@ impl CreateSocket {
     }
 }
 
-impl OpCode for CreateSocket {
+unsafe impl OpCode for CreateSocket {
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision> {
         Ok(Decision::Blocking)
     }
@@ -667,7 +667,7 @@ impl<S: AsFd> OpCode for ShutdownSocket<S> {
     }
 }
 
-impl OpCode for CloseSocket {
+unsafe impl OpCode for CloseSocket {
     fn pre_submit(self: Pin<&mut Self>) -> io::Result<Decision> {
         Ok(Decision::Blocking)
     }
diff --git a/compio-driver/src/sys/stub/mod.rs b/compio-driver/src/sys/stub/mod.rs
index 6493168c..aa0d161e 100644
--- a/compio-driver/src/sys/stub/mod.rs
+++ b/compio-driver/src/sys/stub/mod.rs
@@ -30,7 +30,7 @@ impl Extra {
 }
 
 /// Operations.
-pub trait OpCode {}
+pub unsafe trait OpCode {}
 
 pub mod op;
 
diff --git a/compio-driver/src/sys/stub/op.rs b/compio-driver/src/sys/stub/op.rs
index 0d8c2239..9f72aac0 100644
--- a/compio-driver/src/sys/stub/op.rs
+++ b/compio-driver/src/sys/stub/op.rs
@@ -24,9 +24,9 @@ impl<
 {
 }
 
-impl OpCode for OpenFile {}
+unsafe impl OpCode for OpenFile {}
 
-impl OpCode for CloseFile {}
+unsafe impl OpCode for CloseFile {}
 
 impl<S: AsFd> OpCode for TruncateFile<S> {}
 
@@ -68,7 +68,7 @@ impl PathStat {
     }
 }
 
-impl OpCode for PathStat {}
+unsafe impl OpCode for PathStat {}
 
 impl IntoInner for PathStat {
     type Inner = Stat;
@@ -96,21 +96,21 @@ impl<T: IoVectoredBuf, S: AsFd> OpCode for WriteVectored<T, S> {}
 
 impl<S: AsFd> OpCode for Sync<S> {}
 
-impl OpCode for Unlink {}
+unsafe impl OpCode for Unlink {}
 
-impl OpCode for CreateDir {}
+unsafe impl OpCode for CreateDir {}
 
-impl OpCode for Rename {}
+unsafe impl OpCode for Rename {}
 
-impl OpCode for Symlink {}
+unsafe impl OpCode for Symlink {}
 
-impl OpCode for HardLink {}
+unsafe impl OpCode for HardLink {}
 
-impl OpCode for CreateSocket {}
+unsafe impl OpCode for CreateSocket {}
 
 impl<S: AsFd> OpCode for ShutdownSocket<S> {}
 
-impl OpCode for CloseSocket {}
+unsafe impl OpCode for CloseSocket {}
 
 impl<S: AsFd> OpCode for Accept<S> {}
 
diff --git a/compio-process/src/windows.rs b/compio-process/src/windows.rs
index 91285cb0..0aa42b51 100644
--- a/compio-process/src/windows.rs
+++ b/compio-process/src/windows.rs
@@ -28,7 +28,7 @@ impl WaitProcess {
     }
 }
 
-impl OpCode for WaitProcess {
+unsafe impl OpCode for WaitProcess {
     fn op_type(&self) -> OpType {
         OpType::Event(self.child.as_raw_handle() as _)
     }
diff --git a/compio-runtime/tests/event.rs b/compio-runtime/tests/event.rs
index 9c51f1d3..3a805fcb 100644
--- a/compio-runtime/tests/event.rs
+++ b/compio-runtime/tests/event.rs
@@ -35,7 +35,7 @@ fn win32_event() {
         event: OwnedHandle,
     }
 
-    impl OpCode for WaitEvent {
+    unsafe impl OpCode for WaitEvent {
         fn op_type(&self) -> OpType {
             OpType::Event(self.event.as_raw_handle() as _)
         }