[Bugfix][Profiler] Fix API server crash on double /stop_profile - #51678
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Hi @aijanai, the pre-commit checks have failed. Please run: uv pip install pre-commit>=4.5.1
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Hi @aijanai, the pre-commit checks have failed. Please run: uv pip install pre-commit>=4.5.1
pre-commit install
pre-commit run --all-filesThen, commit the changes and push to your branch. For future commits, |
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Please note I had to give |
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Hi @aijanai, the pre-commit checks have failed. Please run: uv pip install pre-commit>=4.5.1
pre-commit install
pre-commit run --all-filesThen, commit the changes and push to your branch. For future commits, |
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✅ @aijanai, CI is now available for this PR.
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I'm surprised it passes pre-commit at all
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/ci run |
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✅ Triggered Buildkite CI #86375 for commit |
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/ci run |
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✅ Triggered Buildkite CI #86407 for commit |
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/ci run |
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✅ Triggered Buildkite CI #86563 for commit |
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/ci retry |
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✅ Queued 1 failed job(s) for retry in Buildkite CI #86563. |
AsyncLLM used a raw torch.profiler.profile whose start()/stop() are not idempotent. Calling /stop_profile twice (or /start_profile twice) invokes the underlying stop() again on an already-stopped session, which either raises "RuntimeError: Can't disable Kineto profiler when it's not running" (HTTP 500) or, with a large trace, segfaults the API server inside ActivityTraceWrapper::save (use-after-free of the freed Kineto trace). The worker-side profiler already guards against this via WorkerProfiler, whose start()/stop() short-circuit on self._active. Reuse the same TorchProfilerWrapper for the frontend AsyncLLM profiler so both sides share the idempotent guards. start_profile/stop_profile are unchanged: they already call self.profiler.start/stop, now routed through the guarded wrapper (which also builds the tensorboard trace handler from profiler_config). Repro: POST /start_profile -> /stop_profile -> /stop_profile before: 200 / 200 / 500 (or segfault with a large trace) after: 200 / 200 / 200 (second stop is a no-op) Also, regenerate `pre-commit run --all-files`. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Signed-off-by: Alberto Massidda <albertomassidda@aol.com> Signed-off-by: Alberto Massidda <amassidda@nvidia.com>
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/ci retry |
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✅ Triggered Buildkite CI #86652 for commit |
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/ci run |
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✅ CI is already running for this commit: https://buildkite.com/vllm/ci/builds/86652 |
…-project#51678) Signed-off-by: Alberto Massidda <amassidda@nvidia.com> Co-authored-by: Alberto Massidda <amassidda@nvidia.com>
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@aijanai this PR seems break the cuda nsys profiler, may you please take a look? It removed the initialization of self.profiler = None for non-Torch profilers, so /start_profile raises an AttributeError before triggering cudaProfilerStart(). Nsight Systems was installed successfully and is not the cause. |
…-project#51678) Signed-off-by: Alberto Massidda <amassidda@nvidia.com> Co-authored-by: Alberto Massidda <amassidda@nvidia.com>
5 participants
Purpose
Fixes #51676
Test Plan
Start vLLM
vllm serve Qwen/Qwen3.5-0.8B --max-model-len 262144 --reasoning-parser qwen3 --profiler-config '{"profiler":"torch","torch_profiler_dir":"vllm-prof-test/"}' --gpu-memory-utilization 0.6 --max-model-len 32768 --max-num-seqs 128enable profiler
generate some load
stop the profiler twice (you can even run the two calls concurrently, the second causes the segfault)
Test Result