# NousResearch/hermes-agent · Fix infinite process poll loop and exit reconciliation

## Open now

- Nothing open on GitHub.

These members address a bug where process polling could loop infinitely, freezing the Gateway, along with related fixes for reconciling process exit state on Windows and in reader-thread race conditions.

## TL;DR

- 4 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 1 merged PR(s), 2 PR(s) closed without merging.
- A fix was merged to main in PR #17430. Verify it addresses your case.
- **Recommended:** read PR #17430 (and any competing PRs below) before filing. Confirm the merged change covers your symptom.

## Maintainer resolution verdict

- Internal-tracker verdict over this cluster's issue members: `resolved` · deciding PR(s): `pr-17430`. This is distinct from the fix status above. Weigh it yourself.

## How this cluster was grouped

- Link evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.
- Pairwise link density `0.50`: the share of member pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36. `1.00` means every pair is linked.

## Closed / duplicate issues

- #17327: \[Bug\]: process poll 无限轮询导致 Gateway 卡死

## Prior & competing PRs

- **#17430: fix(process): reconcile session.exited against real child exit in poll/wait**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`
  - files: `tests/tools/test_process_registry.py`, `tools/process_registry.py`
  - fix hunks:
  - `tests/tools/test_process_registry.py`

    ```diff
    @@ -103,6 +103,134 @@ def test_poll_exited(self, registry):
             assert result["exit_code"] == 0
     
     
    +# =========================================================================
    +# Orphaned-pipe reconciliation (issue #17327)
    +# =========================================================================
    +
    [redacted:email](sys.platform == "win32", reason="POSIX-only: uses setsid/fcntl")
    +class TestOrphanedPipeReconciliation:
    +    """Regression tests for issue #17327.
    +
    +    `hermes update` in Feishu spawned a background subprocess that restarted
    +    the gateway; the direct child exited quickly but a descendant daemon
    +    held the stdout pipe open. `_reader_loop.finally` never ran, so
    +    `session.exited` stayed False and the agent polled 74 times over 7
    +    minutes, all returning `status: running`.
    +
    +    The fix is `_reconcile_local_exit()`: poll() and wait() now check the
    +    direct `Popen.poll()` before trusting `session.exited`.
    +    """
    +
    +    def test_reconcile_flips_exited_when_direct_child_done(self, registry):
    +        """Direct child exited but reader thread is blocked on orphaned pipe."""
    +        # Simulate the orphaned-pipe scenario: direct child exited, but a
    +        # descendant holds stdout open so the reader never sees EOF.
    +        # Approach: spawn `sh -c 'sleep 10 &'` with setsid — sh forks the
    +        # sleep into a new session group, exits immediately, but sleep
    +        # inherits the stdout pipe and keeps it open.
    +        proc = subprocess.Popen(
    +            ["sh", "-c", "exec 1>&2; ( sleep 30 ) & disown; exit 0"],
    +            stdout=subprocess.PIPE,
    +            stderr=subprocess.STDOUT,
    +            preexec_fn=os.setsid,
    +        )
    +
    +        s = _make_session(sid="proc_orphan_test")
    +        s.process = proc
    +        s.pid = proc.pid
    +        registry._running[s.id] = s
    +
    +        # Wait for the direct child to exit. We don't start a reader thread,
    +        # so session.exited stays False (mimicking the stuck-reader state).
    +        assert _wait_until(lambda: proc.poll() is not None, timeout=5.0), (
    +            "Direct child should exit quickly (sh exits, sleep descendant "
    +            "holds the pipe open)"
    +        )
    +
    +        # Before the fix: poll would return "running" forever.
    +        # After the fix: poll reconciles against proc.poll() and flips.
    +        assert s.exited is False  # Precondition: reader hasn't updated it.
    +        result = registry.poll(s.id)
    +        assert result["status"] == "exited", (
    +            f"Expected reconciled 'exited' status; got {result!r}. "
    +            "This is issue #17327 — reader is blocked on orphaned pipe."
    +        )
    +        assert result["exit_code"] == 0
    +        assert s.exited is True
    +        assert s.id in registry._finished
    +        assert s.id not in registry._running
    +
    +        # Clean up the orphaned descendant.
    +        try:
    +            os.killpg(os.getpgid(proc.pid), signal.SIGKILL)
    +        except (ProcessLookupError, PermissionError):
    +            pass
    +
    +    def test_reconcile_noop_when_child_still_running(self, registry):
    +        """Reconcile must NOT flip exited when the direct child is alive."""
    +        proc = _spawn_python_sleep(5.0)
    +        s = _make_session(sid="proc_running_test")
    +        s.process = proc
    +        s.pid = proc.pid
    +        registry._running[s.id] = s
    +
    +        result = registry.poll(s.id)
    +        assert result["status"] == "running"
    +        assert s.exited is False
    +
    +        proc.kill()
    +        proc.wait()
    +
    +    def test_reconcile_noop_on_already_exited(self, registry):
    +        """Reconcile is a no-op when session.exited is already True."""
    +        s = _make_session(sid="proc_already_exited", exited=True, exit_code=7)
    +        s.process = MagicMock()
    +        s.process.poll = MagicMock(return_value=0)  # Would say exit 0
    +        registry._finished[s.id] = s
    +
    +        registry._reconcile_local_exit(s)
    +        # Must not overwrite the existing exit_code with proc.poll()'s 0.
    +        assert s.exit_code == 7
    +
    +    def test_reconcile_noop_on_no_process(self, registry):
    +        """Reconcile is a no-op for sessions without a local Popen (env/PTY)."""
    +        s = _make_session(sid="proc_no_popen")
    +        assert getattr(s, "process", None) is None
    +        # Must not raise.
    +        registry._reconcile_local_exit(s)
    +        assert s.exited is False
    +
    +    def test_wait_returns_when_reader_blocked(self, registry):
    +        """wait() must also reconcile — not just poll()."""
    +        proc = subprocess.Popen(
    +            ["sh", "-c", "( sleep 30 ) & disown; exit 0"],
    +            stdout=subprocess.PIPE,
    +            stderr=subprocess.STDOUT,
    +            preexec_fn=os.setsid,
    +        )
    +
    +        s = _make_session(sid="proc_wait_orphan")
    +        s.process = proc
    +        s.pid = proc.pid
    +        registry._running[s.id] = s
    +
    +        assert _wait_until(lambda: proc.poll() is not None, timeout=5.0)
    +
    +        start = time.monotonic()
    +        result = registry.wait(s.id, timeout=10)
    +        elapsed = time.monotonic() - start
    +
    +        assert result["status"] == "exited", result
    +        assert elapsed < 5.0, (
    +            f"wait() should return ~immediately via reconcile; took {elapsed:.1f}s"
    +        )
    +
    +        try:
    +            os.killpg(os.getpgid(proc.pid), signal.SIGKILL)
    +        except (ProcessLookupError, PermissionError):
    +            pass
    +
    +
     # =========================================================================
     # Read log
     # =========================================================================
    ```
  - `tools/process_registry.py`

    ```diff
    @@ -800,6 +800,78 @@ def get(self, session_id: str) -> Optional[ProcessSession]:
                 session = self._running.get(session_id) or self._finished.get(session_id)
             return self._refresh_detached_session(session)
     
    +    def _reconcile_local_exit(self, session: "ProcessSession") -> None:
    +        """Reconcile session.exited against the real child process state.
    +
    +        The reader thread (`_reader_loop`) sets `session.exited = True` only
    +        in its `finally` block, which runs when `stdout.read()` returns EOF.
    +        If the direct `Popen` child has exited but a descendant process (e.g.
    +        a daemon spawned by `hermes update` restarting the gateway) is still
    +        holding the stdout pipe open, the reader blocks forever and poll()
    +        keeps returning "running" indefinitely (issue #17327 — 74 polls over
    +        7 minutes on Feishu).
    +
    +        This helper closes that window: when `session.exited` is still False
    +        but the direct child's `Popen.poll()` reports an exit code, drain any
    +        readable bytes non-blocking and flip `session.exited`. The orphaned
    +        reader thread remains stuck on its blocking `read()` but is a daemon
    +        thread and will be reaped with the process.
    +
    +        Safe no-op on sessions without a local `Popen` (env/PTY), already-
    +        exited sessions, and detached-recovered sessions.
    +        """
    +        if session is None or session.exited:
    +            return
    +        proc = getattr(session, "process", None)
    +        if proc is None:
    +            return
    +        try:
    +            rc = proc.poll()
    +        except Exception:
    +            return
    +        if rc is None:
    +            return  # Direct child still running — reader block is legitimate.
    +
    +        # Direct child exited. Try to drain any bytes the reader hasn't
    +        # consumed yet. This is best-effort: if the pipe is held open by a
    +        # descendant, the non-blocking read returns what's immediately
    +        # available and we stop.
    +        drained = ""
    +        stdout = getattr(proc, "stdout", None)
    +        if stdout is not None and not _IS_WINDOWS:
    +            try:
    +                import fcntl
    +                fd = stdout.fileno()
    +                flags = fcntl.fcntl(fd, fcntl.F_GETFL)
    +                fcntl.fcntl(fd, fcntl.F_SETFL, flags | os.O_NONBLOCK)
    +                try:
    +                    chunk = stdout.read()
    +                    if chunk:
    +                        drained = chunk if isinstance(chunk, str) else chunk.decode("utf-8", errors="replace")
    +                except (BlockingIOError, OSError, ValueError):
    +                    pass
    +                finally:
    +                    try:
    +                        fcntl.fcntl(fd, fcntl.F_SETFL, flags)
    +                    except Exception:
    +                        pass
    +            except Exception as e:
    +                logger.debug("Non-blocking drain failed for %s: %s", session.id, e)
    +
    +        with session._lock:
    +            if drained:
    +                session.output_buffer += drained
    +                if len(session.output_buffer) > session.max_output_chars:
    +                    session.output_buffer = session.output_buffer[-session.max_output_chars:]
    +            session.exited = True
    +            session.exit_code = rc
    +        logger.info(
    +            "Reconciled session %s: direct child exited with code %s but reader "
    +            "was still blocked (orphaned pipe). Flipped to exited.",
    +            session.id, rc,
    +        )
    +        self._move_to_finished(session)
    +
         def poll(self, session_id: str) -> dict:
             """Check status and get new output for a background process."""
             from tools.ansi_strip import strip_ansi
    ```

    ```diff
    @@ -808,6 +880,10 @@ def poll(self, session_id: str) -> dict:
             if session is None:
                 return {"status": "not_found", "error": f"No process with ID {session_id}"}
     
    +        # Reconcile against real child state before reading session.exited.
    +        # Guards against orphaned-pipe reader hangs (issue #17327).
    +        self._reconcile_local_exit(session)
    +
             with session._lock:
                 output_preview = strip_ansi(session.output_buffer[-1000:]) if session.output_buffer else ""
     
    ```

    ```diff
    @@ -898,6 +974,10 @@ def wait(self, session_id: str, timeout: int = None) -> dict:
     
             while time.monotonic() < deadline:
                 session = self._refresh_detached_session(session)
    +            # Reconcile against real child state — guards against orphaned-
    +            # pipe reader hangs where the reader is blocked but the direct
    +            # child has already exited (issue #17327).
    +            self._reconcile_local_exit(session)
                 if session.exited:
                     self._completion_consumed.add(session_id)
                     result = {
    ```
- **#17346: fix: prevent infinite process poll loop from reader-thread race (#17327)**. closed without merge
  - maintainer direction: category `implemented_elsewhere`; implication `superseded`; refs `20b759cd0`, `#17430`, `#17327`
- **#47733: fix(process_registry): add Windows drain path in _reconcile_local_exit**. closed without merge
  - maintainer direction: category `uncategorized`; implication `needs_llm`

## Fix status

- Merged to main in PR #17430 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-04-29`.