[Tokenizer] Fix abort racing server crash when large amount of aborts (#28341)

python/sglang/srt/managers/tokenizer_manager.py

@@ -2654,7 +2654,19 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
     def _handle_abort_req(self, recv_obj: AbortReq):
         if is_health_check_generate_req(recv_obj):
             return
-        state = self.rid_to_state[recv_obj.rid]
+        # Two scheduler messages can race in handle_loop for the same rid: a
+        # batch output that finishes it normally (deletes rid_to_state[rid])
+        # and this abort echo. If the finish wins, the rid is already gone and
+        # there is nothing left to abort. Common under mass client
+        # disconnects, amplified by prefix / abort_all fan-out.
+        state = self.rid_to_state.get(recv_obj.rid)
+        if state is None:
+            logger.info(
+                "Abort request for rid=%s not found in rid_to_state; "
+                "likely already finished/removed.",
+                recv_obj.rid,
+            )
+            return
         state.finished = True
         state.time_stats.set_finished_time()