Fix dead contexts clobber idle pools

src/context/context.rs

@@ -60,6 +60,9 @@ impl Status {
     pub fn is_soft_blocked(&self) -> bool {
         matches!(self, Self::Blocked)
     }
+    pub fn is_dead(&self) -> bool {
+        matches!(self, Self::Dead { .. })
+    }
 }
 
 #[derive(Clone, Debug)]

src/context/switch.rs

@@ -336,6 +336,9 @@ fn wakeup_contexts(token: &mut CleanLockToken, switch_time: u128) -> Vec<(usize,
                     continue;
                 }
             }
+        } else if guard.status.is_dead() {
+            // TODO: who hold this dead context?
+            continue;
         }
 
         if guard.status.is_runnable() && !guard.running {