diff --git a/cms/grading/tasktypes/Interactive.py b/cms/grading/tasktypes/Interactive.py
index 9f3d8b1498..b2fad2a8aa 100644
--- a/cms/grading/tasktypes/Interactive.py
+++ b/cms/grading/tasktypes/Interactive.py
@@ -252,7 +252,11 @@ def evaluate(self, job, file_cacher):
                 stdin=subprocess.DEVNULL,
                 stdout=subprocess.PIPE,
             )
-            stdout, _ = p.communicate(timeout=self.controller_wall_limit * 2)
+            try:
+                stdout, _ = p.communicate(timeout=self.controller_wall_limit * 2)
+            except subprocess.TimeoutExpired:
+                p.kill()
+                stdout, _ = p.communicate()
 
             KEEPER_ERROR_MESSAGE = "Internal error in interactive keeper"
 
diff --git a/cms/grading/tasktypes/interactive_keeper.py b/cms/grading/tasktypes/interactive_keeper.py
index 0399cb77c9..26bd705fff 100644
--- a/cms/grading/tasktypes/interactive_keeper.py
+++ b/cms/grading/tasktypes/interactive_keeper.py
@@ -87,10 +87,8 @@ def main():
     for i in range(process_limit):
         c_to_u_r, c_to_u_w = os.pipe()
         u_to_c_r, u_to_c_w = os.pipe()
-        os.set_inheritable(c_to_u_r, True)
         os.set_inheritable(c_to_u_w, True)
         os.set_inheritable(u_to_c_r, True)
-        os.set_inheritable(u_to_c_w, True)
         pipes.append({"c_to_u": (c_to_u_r, c_to_u_w), "u_to_c": (u_to_c_r, u_to_c_w)})
 
     controller_sandbox = Sandbox(0, shard, name="controller", temp_dir=temp_dir)
@@ -165,7 +163,8 @@ def main():
                 wait=False,
             )
 
-            os.close(p["c_to_u"][0])
+            # We do not close p["c_to_u"][0] -- it only risks crashing the
+            # controller with SIGPIPE if the submission exits early.
             os.close(p["u_to_c"][1])
 
             try: