[bug] Fix deadlock with pause resume and collective_rpc#37024
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robertgshaw2-redhat merged 2 commits intovllm-project:mainfrom Mar 19, 2026
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[bug] Fix deadlock with pause resume and collective_rpc#37024robertgshaw2-redhat merged 2 commits intovllm-project:mainfrom
robertgshaw2-redhat merged 2 commits intovllm-project:mainfrom
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hao-aaron
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We have validated this internally on a large scale run (36 inference nodes) with P/D and it has fixed the issue mentioned above. |
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…#37024) Signed-off-by: hao-aaron <ahao@anyscale.com>
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PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
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Mar 24, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
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Mar 25, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
junjzhang
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Mar 25, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
junjzhang
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Mar 25, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
junjzhang
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Mar 25, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
junjzhang
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Mar 25, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
junjzhang
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Mar 26, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
SouthWest7
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Mar 27, 2026
…#37024) Signed-off-by: hao-aaron <ahao@anyscale.com>
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…#37024) Signed-off-by: hao-aaron <ahao@anyscale.com>
junjzhang
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Mar 27, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
junjzhang
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Mar 27, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
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…#37024) Signed-off-by: hao-aaron <ahao@anyscale.com> Signed-off-by: Monishver Chandrasekaran <monishverchandrasekaran@gmail.com>
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…#37024) Signed-off-by: hao-aaron <ahao@anyscale.com>
junjzhang
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Mar 28, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
junjzhang
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Mar 28, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
junjzhang
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Mar 28, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
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PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
junjzhang
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Mar 30, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
vrdn-23
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Mar 30, 2026
…#37024) Signed-off-by: hao-aaron <ahao@anyscale.com> Signed-off-by: Vinay Damodaran <vrdn@hey.com>
junjzhang
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Mar 31, 2026
PR vllm-project#37024 fixed the `START_DP_WAVE` / pause race in `add_request()` by checking `scheduler.pause_state` before setting `engines_running = True`. However, the same unguarded pattern exists in `DPEngineCoreProc._handle_client_request()`. When `pause_generation()` + `collective_rpc()` is used for online weight update, a late `START_DP_WAVE` from the DP coordinator can re-arm the engine loop via `_handle_client_request` while the engine is paused. The re-armed engine enters the dummy-batch ALLREDUCE while the peer engine is in `collective_rpc`, causing a one-sided collective deadlock. Add the same `PauseState.UNPAUSED` guard that vllm-project#37024 added to `add_request()`. Fixes: vllm-project#36594 Signed-off-by: Junjie ZHANG <51326516+junjzhang@users.noreply.github.com>
EricccYang
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Apr 1, 2026
…#37024) Signed-off-by: hao-aaron <ahao@anyscale.com> Signed-off-by: EricccYang <yangyang4991@gmail.com>
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Purpose
closes #36594
Test Plan
pending large scale training run
Test Result
Essential Elements of an Effective PR Description Checklist
supported_models.mdandexamplesfor a new model.