diff --git a/kernel/src/fs/utils/channel.rs b/kernel/src/fs/utils/channel.rs
index 407efcb75..f4efca68d 100644
--- a/kernel/src/fs/utils/channel.rs
+++ b/kernel/src/fs/utils/channel.rs
@@ -6,7 +6,7 @@ use aster_rights::{Read, ReadOp, TRights, Write, WriteOp};
 use aster_rights_proc::require;
 
 use crate::{
-    events::{IoEvents, Observer},
+    events::IoEvents,
     prelude::*,
     process::signal::{PollHandle, Pollee},
     util::{
@@ -98,22 +98,6 @@ macro_rules! impl_common_methods_for_channel {
         pub fn poll(&self, mask: IoEvents, poller: Option<&mut PollHandle>) -> IoEvents {
             self.this_end().pollee.poll(mask, poller)
         }
-
-        pub fn register_observer(
-            &self,
-            observer: Weak<dyn Observer<IoEvents>>,
-            mask: IoEvents,
-        ) -> Result<()> {
-            self.this_end().pollee.register_observer(observer, mask);
-            Ok(())
-        }
-
-        pub fn unregister_observer(
-            &self,
-            observer: &Weak<dyn Observer<IoEvents>>,
-        ) -> Option<Weak<dyn Observer<IoEvents>>> {
-            self.this_end().pollee.unregister_observer(observer)
-        }
     };
 }
 
diff --git a/kernel/src/process/signal/poll.rs b/kernel/src/process/signal/poll.rs
index 923d51b87..0c990993c 100644
--- a/kernel/src/process/signal/poll.rs
+++ b/kernel/src/process/signal/poll.rs
@@ -64,34 +64,6 @@ impl Pollee {
         poller.pollees.push(Arc::downgrade(&self.inner));
     }
 
-    /// Register an IoEvents observer.
-    ///
-    /// A registered observer will get notified (through its `on_events` method)
-    /// every time new events specified by the `mask` argument happen on the
-    /// pollee (through the `add_events` method).
-    ///
-    /// If the given observer has already been registered, then its registered
-    /// event mask will be updated.
-    ///
-    /// Note that the observer will always get notified of the events in
-    /// `IoEvents::ALWAYS_POLL` regardless of the value of `mask`.
-    pub fn register_observer(&self, observer: Weak<dyn Observer<IoEvents>>, mask: IoEvents) {
-        let mask = mask | IoEvents::ALWAYS_POLL;
-        self.inner.subject.register_observer(observer, mask);
-    }
-
-    /// Unregister an IoEvents observer.
-    ///
-    /// If such an observer is found, then the registered observer will be
-    /// removed from the pollee and returned as the return value. Otherwise,
-    /// a `None` will be returned.
-    pub fn unregister_observer(
-        &self,
-        observer: &Weak<dyn Observer<IoEvents>>,
-    ) -> Option<Weak<dyn Observer<IoEvents>>> {
-        self.inner.subject.unregister_observer(observer)
-    }
-
     /// Add some events to the pollee's state.
     ///
     /// This method wakes up all registered pollers that are interested in