Fix: abort handling for dispatched requests after client disconnect (#35255)

Signed-off-by: Shijin Zhang <75300765+Dovis01@users.noreply.github.com>
Co-authored-by: Xinyuan Tong <xinyuantong.cs@gmail.com>
Co-authored-by: cctry <cctry@fb.com>

python/sglang/srt/managers/scheduler.py

@@ -3348,6 +3348,11 @@ class Scheduler(
             # it. Drop the marker once the request is actually gone.
             if req.finished() or not req.kv.holds_kv:
                 self._pending_chunked_abort_req = None
+                return
+            # The request moved to another scheduler queue after abort_request
+            # deferred it, so retry against its current location.
+            self._pending_chunked_abort_req = None
+            self.abort_request(AbortReq(rid=req.rid))
             return
 
         prepare_abort(req, "Aborted")

python/sglang/srt/managers/tokenizer_manager.py

@@ -233,6 +233,9 @@ class ReqState:
     last_completion_tokens: int = 1
     ttft_observed: bool = False
 
+    dispatched: bool = False
+    abort_sent: bool = False
+
     # For streaming output
     last_output_offset: int = 0
 
@@ -799,6 +802,7 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
                 )
 
         self._init_req_state(obj, request)
+        request_rids = {obj.rid} if obj.is_single else set(obj.rid)
         try:
             if get_disagg().language_only:
                 self._handle_epd_disaggregation_encode_request(obj)
@@ -822,17 +826,19 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
                     async for response in self._wait_one_response(obj, request):
                         yield response
                 else:
-                    async for response in self._handle_batch_request(obj, request):
+                    async for response in self._handle_batch_request(
+                        obj, request, request_rids
+                    ):
                         yield response
         except BaseException:
             # _init_req_state created a rid_to_state entry per (sub-)request up
             # front. The normal remover is the scheduler-response path
             # (_handle_batch_output), so a failure *before* a request reaches the
             # scheduler -- e.g. input-length validation rejecting an over-context
-            # request -- would otherwise leak those entries forever. Drop any that
+            # request -- would otherwise leak those entries forever. Drop
-            # are still pending; entries already removed on the normal completion
+            # undelivered states, but abort dispatched requests for scheduler-side
-            # path are left untouched (pop is a no-op).
+            # cleanup.
-            self._discard_pending_req_states(obj)
+            self._release_req_states_on_failure(request_rids)
             raise
 
     def _detect_input_format(
@@ -1571,6 +1577,7 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
             time_stats = tokenized_obj.time_stats
             tokenized_obj.wrap_pickle_fields()
             self._dispatch_to_scheduler(tokenized_obj)
+            self._mark_state_dispatched(tokenized_obj.rid)
             dispatched = True
             tokenized_obj.time_stats = time_stats
             tokenized_obj.time_stats.set_api_server_dispatch_finish_time()
@@ -1578,6 +1585,16 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
             if not dispatched:
                 self.cuda_vmm_feature_transport.cancel_for_dispatch(prepared_mm_items)
 
+    def _mark_state_dispatched(self, rid: str):
+        """Record that *rid* reached the scheduler.
+
+        Only dispatched requests are aborted (not discarded) by the
+        handler-failure cleanup; see _release_req_states_on_failure.
+        """
+        state = self.rid_to_state.get(rid)
+        if state is not None:
+            state.dispatched = True
+
     async def _send_batch_request(
         self,
         tokenized_objs: List[
@@ -1605,6 +1622,8 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
                 batch_req = BatchTokenizedEmbeddingReqInput(batch=tokenized_objs)
 
             self._dispatch_to_scheduler(batch_req)
+            for tokenized_obj in tokenized_objs:
+                self._mark_state_dispatched(tokenized_obj.rid)
             dispatched = True
             for tokenized_obj, time_stat in zip(tokenized_objs, time_stats):
                 tokenized_obj.time_stats = time_stat
@@ -1819,7 +1838,10 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
         self,
         obj: Union[GenerateReqInput, EmbeddingReqInput],
         request: Optional[fastapi.Request] = None,
+        request_rids: Optional[set[str]] = None,
     ):
+        if request_rids is None:
+            request_rids = set(obj.rid)
         batch_size = obj.batch_size
 
         generators = []
@@ -1885,6 +1907,7 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
                 tokenized_obj.sampling_params.max_new_tokens = 0
                 tokenized_obj.stream = False
                 self._init_req_state(tmp_obj)
+                request_rids.add(tmp_obj.rid)
                 await self._send_one_request(tokenized_obj)
                 await self._wait_one_response(tmp_obj, request).__anext__()
 
@@ -1901,6 +1924,7 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
                         ]
                     tokenized_obj.rid = tmp_obj.regenerate_rid()
                     self._init_req_state(tmp_obj)
+                    request_rids.add(tmp_obj.rid)
                     state = self.rid_to_state[tmp_obj.rid]
                     tokenized_obj.time_stats = state.time_stats
                     if tmp_obj.return_prompt_token_ids:
@@ -1970,14 +1994,21 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
         if not abort_all and not rid:
             logger.warning("Ignore abort_request with empty rid and abort_all=False")
             return
-        if (
+        state = None if abort_all else self.rid_to_state.get(rid)
-            not abort_all
+        if not abort_all:
-            and get_serving().tokenizer_worker_num == 1
+            if state is not None:
-            and rid not in self.rid_to_state
+                if state.abort_sent:
-        ):
+                    return
-            return
+                state.abort_sent = True
+            elif get_serving().tokenizer_worker_num == 1:
+                return
         req = AbortReq(rid=rid, abort_all=abort_all)
-        self._dispatch_to_scheduler(req)
+        try:
+            self._dispatch_to_scheduler(req)
+        except BaseException:
+            if state is not None:
+                state.abort_sent = False
+            raise
         if self.enable_metrics:
             # TODO: also use custom_labels from the request
             self.metrics_collector.observe_one_aborted_request(
@@ -2140,10 +2171,9 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
         # Abort the request if the client is disconnected.
         async def abort_request():
             await asyncio.sleep(2)
-            if obj.is_single:
+            rids = [obj.rid] if obj.is_single else obj.rid
-                self.abort_request(obj.rid)
+            for rid in rids:
-            else:
+                if rid in self.rid_to_state:
-                for rid in obj.rid:
                     self.abort_request(rid)
 
         background_tasks = BackgroundTasks()
@@ -3455,19 +3485,23 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
                 time_stats.init_trace_ctx(rid, bootstrap_room, external_trace_header)
             time_stats.set_created_time(created_time)
 
-    def _discard_pending_req_states(self, obj):
+    def _release_req_states_on_failure(self, rids: Iterable[str]):
-        """Drop rid_to_state entries created by _init_req_state for *obj*.
+        """Release rid_to_state entries created for a failed handler.
 
-        Safe to call after a partial/failed dispatch: only entries still present
+        Undelivered states are removed locally. Dispatched requests are aborted
-        are removed, and the scheduler-response path looks up state with
+        and retained until the scheduler response removes them.
-        ``.get(...)`` so a later output for a discarded rid is ignored, not fatal.
         """
-        if not hasattr(obj, "is_single") or obj.is_single:
-            rids = [obj.rid]
-        else:
-            rids = obj.rid
         for rid in rids:
-            self.rid_to_state.pop(rid, None)
+            state = self.rid_to_state.get(rid)
+            if state is None:
+                continue
+            if state.dispatched:
+                try:
+                    self.abort_request(rid)
+                except Exception:
+                    logger.exception("Failed to abort request %s during cleanup", rid)
+            else:
+                del self.rid_to_state[rid]
 
     def _should_dispatch_to_encoder(
         self, obj: Union[GenerateReqInput, EmbeddingReqInput]

test/registered/unit/managers/test_scheduler_chunked_abort_race.py

@@ -0,0 +1,69 @@
+"""Tests for deferred chunked-prefill aborts."""
+
+import unittest
+from types import SimpleNamespace
+from unittest.mock import Mock
+
+from sglang.test.ci.ci_register import register_cpu_ci
+from sglang.test.test_utils import CustomTestCase, maybe_stub_sgl_kernel
+
+maybe_stub_sgl_kernel()
+
+from sglang.srt.managers.scheduler import Scheduler  # noqa: E402
+
+register_cpu_ci(est_time=10, suite="base-a-test-cpu")
+
+
+class _FakeReq:
+    """Minimal stand-in for Req: only the fields the abort paths touch."""
+
+    def __init__(self, rid: str):
+        self.rid = rid
+        # Mirrors Req.kv; the abort paths read only these two predicates.
+        self.kv = SimpleNamespace(holds_kv=True, holds_mamba=False)
+        self.to_finish = None
+        self._finished = False
+
+    def finished(self):
+        return self._finished
+
+
+def _make_scheduler(pending_req, *, chunked_req, running_reqs) -> Scheduler:
+    sched = Scheduler.__new__(Scheduler)
+    sched.chunked_req = chunked_req
+    sched._pending_chunked_abort_req = pending_req
+    sched.waiting_queue = []
+    sched.dllm_config = None
+    sched.grammar_manager = Mock()
+    sched.disaggregation_mode = None
+    sched.enable_hicache_storage = False
+    sched.mm_receiver = None
+    sched.ps = SimpleNamespace(pp_size=1)
+    sched.running_batch = SimpleNamespace(reqs=running_reqs)
+    sched.last_batch = None
+    return sched
+
+
+class TestPendingChunkedAbortRace(CustomTestCase):
+    def test_req_left_chunked_slot_is_aborted(self):
+        req = _FakeReq("zombie_rid")
+        sched = _make_scheduler(req, chunked_req=None, running_reqs=[req])
+
+        sched.process_pending_chunked_abort()
+
+        self.assertIsNotNone(req.to_finish, "recorded abort was never applied")
+        self.assertIsNone(sched._pending_chunked_abort_req)
+
+    def test_finished_req_only_clears_marker(self):
+        req = _FakeReq("done_rid")
+        req._finished = True
+        sched = _make_scheduler(req, chunked_req=None, running_reqs=[])
+
+        sched.process_pending_chunked_abort()
+
+        self.assertIsNone(req.to_finish)
+        self.assertIsNone(sched._pending_chunked_abort_req)
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)

test/registered/unit/managers/test_tokenizer_manager_rid_cleanup.py

@@ -10,11 +10,12 @@ Covers:
   - _handle_batch_output cleans up rid_to_state on finished requests
   - _init_req_state rejects duplicate rids
   - Resubmission succeeds after cleanup
+  - Handler failures clean up pending and dispatched requests
 """
 
 import asyncio
 import unittest
-from unittest.mock import AsyncMock, MagicMock, Mock
+from unittest.mock import AsyncMock, MagicMock, Mock, patch
 
 import msgspec
 
@@ -454,41 +455,88 @@ def _make_generate_obj(rid, is_single):
     return obj
 
 
-class TestDiscardPendingReqStates(CustomTestCase):
+class TestReleaseReqStatesOnFailure(CustomTestCase):
-    """Direct tests for _discard_pending_req_states."""
+    """Direct tests for _release_req_states_on_failure."""
 
-    def test_discard_single(self):
+    def test_undelivered_single_is_dropped(self):
         tm = _make_tokenizer_manager(self)
         rid = "d_single"
         tm.rid_to_state[rid] = _make_req_state(rid)
-        obj = Mock(spec=GenerateReqInput)
+        tm._release_req_states_on_failure([rid])
-        obj.is_single = True
-        obj.rid = rid
-        tm._discard_pending_req_states(obj)
         self.assertNotIn(rid, tm.rid_to_state)
 
-    def test_discard_batch_removes_all(self):
+    def test_undelivered_batch_removes_all(self):
         tm = _make_tokenizer_manager(self)
         rids = ["d0", "d1", "d2"]
         for r in rids:
             tm.rid_to_state[r] = _make_req_state(r)
-        obj = Mock(spec=GenerateReqInput)
+        tm._release_req_states_on_failure(rids)
-        obj.is_single = False
-        obj.rid = list(rids)
-        tm._discard_pending_req_states(obj)
         for r in rids:
             self.assertNotIn(r, tm.rid_to_state)
 
-    def test_discard_ignores_already_removed(self):
+    def test_ignores_already_removed(self):
-        """Popping a rid that is no longer present must not raise."""
+        """A rid that is no longer present must not raise."""
         tm = _make_tokenizer_manager(self)
         tm.rid_to_state["p1"] = _make_req_state("p1")
-        obj = Mock(spec=GenerateReqInput)
+        tm._release_req_states_on_failure(["p1", "already_gone"])
-        obj.is_single = False
-        obj.rid = ["p1", "already_gone"]
-        tm._discard_pending_req_states(obj)  # must not raise
         self.assertNotIn("p1", tm.rid_to_state)
 
+    def test_dispatched_single_is_aborted_and_state_kept(self):
+        tm = _make_tokenizer_manager(self)
+        tm.server_args.tokenizer_worker_num = 1
+        tm._dispatch_to_scheduler = Mock()
+        tm.enable_metrics = True
+        tm.metrics_collector = MagicMock()
+        rid = "d_live"
+        state = _make_req_state(rid)
+        state.dispatched = True
+        tm.rid_to_state[rid] = state
+        tm._release_req_states_on_failure([rid])
+        tm._release_req_states_on_failure([rid])
+
+        sent = [c.args[0] for c in tm._dispatch_to_scheduler.call_args_list]
+        self.assertEqual(
+            [type(m) for m in sent], [AbortReq], "expected exactly one AbortReq"
+        )
+        self.assertEqual(sent[0].rid, rid)
+        self.assertIn(rid, tm.rid_to_state)
+        self.assertTrue(state.abort_sent)
+        tm.metrics_collector.observe_one_aborted_request.assert_called_once()
+
+    def test_dispatched_batch_aborts_delivered_and_drops_rest(self):
+        tm = _make_tokenizer_manager(self)
+        tm.server_args.tokenizer_worker_num = 1
+        tm._dispatch_to_scheduler = Mock()
+        delivered, undelivered = "d_delivered", "d_undelivered"
+        live = _make_req_state(delivered)
+        live.dispatched = True
+        tm.rid_to_state[delivered] = live
+        tm.rid_to_state[undelivered] = _make_req_state(undelivered)
+        tm._release_req_states_on_failure([delivered, undelivered])
+
+        sent = [c.args[0] for c in tm._dispatch_to_scheduler.call_args_list]
+        self.assertEqual([type(m) for m in sent], [AbortReq])
+        self.assertEqual(sent[0].rid, delivered)
+        self.assertIn(delivered, tm.rid_to_state)
+        self.assertNotIn(undelivered, tm.rid_to_state)
+
+    def test_abort_failure_does_not_stop_cleanup(self):
+        tm = _make_tokenizer_manager(self)
+        tm.server_args.tokenizer_worker_num = 1
+        tm._dispatch_to_scheduler = Mock(side_effect=RuntimeError("send failed"))
+        delivered, undelivered = "live", "pending"
+        live = _make_req_state(delivered)
+        live.dispatched = True
+        tm.rid_to_state[delivered] = live
+        tm.rid_to_state[undelivered] = _make_req_state(undelivered)
+
+        with self.assertLogs(level="ERROR"):
+            tm._release_req_states_on_failure([delivered, undelivered])
+
+        self.assertIn(delivered, tm.rid_to_state)
+        self.assertFalse(live.abort_sent)
+        self.assertNotIn(undelivered, tm.rid_to_state)
+
 
 class TestParallelStreamTaskCleanup(CustomTestCase):
     def test_failing_choice_cancels_and_closes_sibling_waiters(self):
@@ -595,6 +643,27 @@ class TestGenerateRequestCleanupOnDispatchFailure(CustomTestCase):
         for r in rids:
             self.assertNotIn(r, tm.rid_to_state)
 
+    def test_parallel_sampling_failure_cleans_generated_rid(self):
+        tm = _make_tm_for_generate(self)
+        obj = GenerateReqInput(
+            text=["hello"],
+            rid=["base"],
+            sampling_params={"n": 2},
+        )
+        tokenized = MagicMock()
+        tokenized.mm_inputs = None
+        tokenized.sampling_params = MagicMock()
+        tm._tokenize_one_request = AsyncMock(return_value=tokenized)
+        tm._send_one_request = Mock(side_effect=RuntimeError("dispatch failed"))
+
+        async def drive():
+            await tm.generate_request(obj).__anext__()
+
+        with self.assertRaisesRegex(RuntimeError, "dispatch failed"):
+            asyncio.run(drive())
+
+        self.assertFalse(tm.rid_to_state)
+
     def test_thinking_budget_rejects_runtime_without_strict_thinking(self):
         tm = _make_tm_for_generate(self)
         obj = GenerateReqInput(
@@ -641,5 +710,52 @@ class TestWaitOneResponseAfterStateFreed(CustomTestCase):
         self.assertEqual(out["text"], "hello")
 
 
+class TestDisconnectAfterDispatchAbortsRequest(CustomTestCase):
+    """Cancellation after dispatch must stop the scheduler request."""
+
+    @patch(
+        "sglang.srt.managers.tokenizer_manager.wrap_shm_features",
+        side_effect=lambda obj: obj,
+    )
+    def test_cancel_after_dispatch_sends_abort_and_keeps_state(self, _wrap_shm):
+        tm = _make_tm_for_generate(self)
+        tm.cuda_vmm_feature_transport = Mock()
+        tm.cuda_vmm_feature_transport.prepare_for_dispatch_async = AsyncMock(
+            return_value=[]
+        )
+        tm._dispatch_to_scheduler = Mock()
+        rid = "disconnect_zombie"
+        obj = _make_generate_obj(rid, is_single=True)
+        obj.return_prompt_token_ids = False
+        tokenized = MagicMock()
+        tokenized.rid = rid
+        tokenized.mm_inputs = None
+        tm._tokenize_one_request = AsyncMock(return_value=tokenized)
+
+        async def drive():
+            task = asyncio.create_task(tm.generate_request(obj).__anext__())
+            for _ in range(100):
+                await asyncio.sleep(0)
+                if tm._dispatch_to_scheduler.called:
+                    break
+            self.assertTrue(
+                tm._dispatch_to_scheduler.called, "request never dispatched"
+            )
+            state = tm.rid_to_state.get(rid)
+            self.assertIsNotNone(state)
+            self.assertTrue(state.dispatched)
+
+            task.cancel()
+            with self.assertRaises(asyncio.CancelledError):
+                await task
+
+        asyncio.run(drive())
+
+        sent = [c.args[0] for c in tm._dispatch_to_scheduler.call_args_list]
+        aborts = [m for m in sent if isinstance(m, AbortReq) and m.rid == rid]
+        self.assertTrue(aborts, "disconnect must send an AbortReq to the scheduler")
+        self.assertIn(rid, tm.rid_to_state)
+
+
 if __name__ == "__main__":
     unittest.main(verbosity=2)

test/registered/unit/multimodal/test_gpu_feature_transport.py

@@ -376,6 +376,7 @@ class TestCudaVmmFeatureTransport(unittest.TestCase):
         from sglang.srt.managers.tokenizer_manager import TokenizerManager
 
         manager = object.__new__(TokenizerManager)
+        manager.rid_to_state = {}
         transport = MagicMock()
         transport.prepare_for_dispatch_async = AsyncMock(return_value=[])
         manager.cuda_vmm_feature_transport = transport
@@ -403,6 +404,7 @@ class TestCudaVmmFeatureTransport(unittest.TestCase):
         )
 
         manager = object.__new__(tokenizer_manager.TokenizerManager)
+        manager.rid_to_state = {}
         transport = MagicMock()
         manager._dispatch_to_scheduler = MagicMock(
             side_effect=RuntimeError("send failed")
@@ -437,6 +439,7 @@ class TestCudaVmmFeatureTransport(unittest.TestCase):
         )
 
         manager = object.__new__(tokenizer_manager.TokenizerManager)
+        manager.rid_to_state = {}
         transport = MagicMock()
         manager._dispatch_to_scheduler = MagicMock()
         time_stats = MagicMock()

test/registered/unit/test_chain_read_ratchet.py

@@ -78,9 +78,25 @@ def _returned_field_names(function):
     returned literal, assignments (annotated or not) to a returned name, a
     literal-key subscript write on it, and `.update(field=...)` on it. A
     spelling this cannot see raises instead of skipping.
+
+    ``overrides[name]`` is also accepted when ``name`` comes from
+    ``for name in ("a", "b", ...)`` -- the keys stay statically enumerable.
     """
     names = set()
     returned = set()
+    # for x in ("a", "b"): ...  ->  {"x": {"a", "b"}}
+    loop_keys = {
+        node.target.id: {elt.value for elt in node.iter.elts}
+        for node in ast.walk(function)
+        if isinstance(node, ast.For)
+        and isinstance(node.target, ast.Name)
+        and isinstance(node.iter, (ast.Tuple, ast.List))
+        and node.iter.elts
+        and all(
+            isinstance(elt, ast.Constant) and isinstance(elt.value, str)
+            for elt in node.iter.elts
+        )
+    }
 
     def top_level_keys(mapping):
         for key in mapping.keys:
@@ -88,6 +104,14 @@ def _returned_field_names(function):
                 raise AssertionError(f"non-literal key in {function.name}")
             names.add(key.value)
 
+    def add_subscript_key(key):
+        if isinstance(key, ast.Constant):
+            names.add(key.value)
+        elif isinstance(key, ast.Name) and key.id in loop_keys:
+            names.update(loop_keys[key.id])
+        else:
+            raise AssertionError(f"non-literal key in {function.name}")
+
     for node in ast.walk(function):
         if isinstance(node, ast.Return) and node.value is not None:
             value = node.value
@@ -114,9 +138,7 @@ def _returned_field_names(function):
                 if isinstance(target, ast.Subscript) and (
                     isinstance(target.value, ast.Name) and target.value.id in returned
                 ):
-                    if not isinstance(target.slice, ast.Constant):
+                    add_subscript_key(target.slice)
-                        raise AssertionError(f"non-literal key in {function.name}")
-                    names.add(target.slice.value)
         if (
             isinstance(node, ast.Call)
             and isinstance(node.func, ast.Attribute)