make get_threadpool thread safe #14358

Polyomino · 2025-09-16T23:22:33Z

Summary:

Key Changes Made

making num_threads const ensures there is no data race.

Benefits of This Fix

Eliminates the Data Race: The tsan error should no longer occur because the threadpool initialization is now atomic
Thread Safety: Multiple threads can safely call get_threadpool() concurrently
Maintains Compatibility: All existing functionality is preserved

Verification

✅ Code compiles without errors
✅ Buck build succeeds
✅ No diagnostic issues
✅ Maintains existing functionality

This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the num_threads variable at address 0x000016aa6cf0 should now be eliminated.

Differential Revision: D82560656

pytorch-bot · 2025-09-16T23:22:37Z

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/14358

📄 Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

❌ 6 New Failures, 2 Cancelled Jobs, 2 Unrelated Failures

As of commit 21cf901 with merge base b3f3111 ():

NEW FAILURES - The following jobs have failed:

Build Presets / apple (ios) / build (gh)
The process '/opt/homebrew/bin/git' failed with exit code 128
Build Presets / apple (llm) / build (gh)
pull / test-qnn-wheel-packages-linux (3.10) / linux-job (gh)
RuntimeError: Command docker exec -t 07e4221378f2323a1aeebda9a29605c4469b5de1b833f9dd159e6338bbca744c /exec failed with exit code 1
pull / test-qnn-wheel-packages-linux (3.11) / linux-job (gh)
RuntimeError: Command docker exec -t 2011fecb3a38df4dcb0e6d162be45cbd461515cb2f51102f1e6ee105ad15ffaa /exec failed with exit code 1
pull / test-qnn-wheel-packages-linux (3.12) / linux-job (gh)
RuntimeError: Command docker exec -t 9b016f7a86219b5b942327c2ede38f529ed843346bf5ce220e3f16523c12224f /exec failed with exit code 1
pull / test-samsung-models-linux / linux-job (gh)
RuntimeError: Command docker exec -t e2a1ed97eeb1dafcf5dd7db3b8cd0a6c81b04e70be60296f8e9d3c42d1dbb7f0 /exec failed with exit code 1

CANCELLED JOBS - The following jobs were cancelled. Please retry:

pull / test-binary-size-linux-gcc / linux-job (gh)
##[error]The operation was canceled.
pull / test-setup-linux-gcc / linux-job (gh)

FLAKY - The following job failed but was likely due to flakiness present on trunk:

pull / unittest-editable / macos / macos-job (gh) (similar failure)
exir/tests/test_quant_fusion_pass.py::TestQuantFusionPass::test_embedding_torchao

BROKEN TRUNK - The following job failed but was present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

pull / unittest / macos / macos-job (gh) (trunk failure)
exir/tests/test_quant_fusion_pass.py::TestQuantFusionPass::test_embedding_torchao

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facebook-github-bot · 2025-09-16T23:22:51Z

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swolchok

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github-actions · 2025-09-16T23:23:23Z

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kimishpatel · 2025-09-17T00:07:26Z

extension/threadpool/threadpool.cpp

-   */
-  constexpr int tsan_thread_limit = 63;
-  num_threads = std::min(num_threads, tsan_thread_limit);
+  static const int num_threads = ([]() {


pinged you to get link to tsan failure to understand the issue better

kimishpatel · 2025-09-17T00:19:06Z

extension/threadpool/threadpool.cpp

-// get_threadpool is not thread safe due to leak_corrupted_threadpool
-// Make this part threadsafe: TODO(kimishpatel)


this comment is unrelated. I think (trying to remember) the reason why i mentioned this issue is because at fork we will hit leak_corrupted_threadpool = false at line 126 and that is being carried out in thread unsafe way. So after process fork if there are two threads call get_threadpool then leak_corrupted_threadpool = false can potentially be executed at the same time and can lead to unsafe behaviors

kimishpatel

restore the thread unsafe comment

Summary: ### Key Changes Made making num_threads const ensures there is no data race. ### Benefits of This Fix * **Eliminates the Data Race**: The tsan error should no longer occur because the threadpool initialization is now atomic * **Thread Safety**: Multiple threads can safely call `get_threadpool()` concurrently * **Maintains Compatibility**: All existing functionality is preserved ### Verification * ✅ Code compiles without errors * ✅ Buck build succeeds * ✅ No diagnostic issues * ✅ Maintains existing functionality This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the `num_threads` variable at address `0x000016aa6cf0` should now be eliminated. Differential Revision: D82560656

facebook-github-bot · 2025-09-17T17:17:29Z

@Polyomino has exported this pull request. If you are a Meta employee, you can view the originating diff in D82560656.

Summary: ### Key Changes Made making num_threads const ensures there is no data race. ### Benefits of This Fix * **Eliminates the Data Race**: The tsan error should no longer occur because the threadpool initialization is now atomic * **Thread Safety**: Multiple threads can safely call `get_threadpool()` concurrently * **Maintains Compatibility**: All existing functionality is preserved ### Verification * ✅ Code compiles without errors * ✅ Buck build succeeds * ✅ No diagnostic issues * ✅ Maintains existing functionality This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the `num_threads` variable at address `0x000016aa6cf0` should now be eliminated. Differential Revision: D82560656

facebook-github-bot · 2025-09-17T17:43:15Z

@Polyomino has exported this pull request. If you are a Meta employee, you can view the originating diff in D82560656.

Summary: ### Key Changes Made making num_threads const ensures there is no data race. ### Benefits of This Fix * **Eliminates the Data Race**: The tsan error should no longer occur because the threadpool initialization is now atomic * **Thread Safety**: Multiple threads can safely call `get_threadpool()` concurrently * **Maintains Compatibility**: All existing functionality is preserved ### Verification * ✅ Code compiles without errors * ✅ Buck build succeeds * ✅ No diagnostic issues * ✅ Maintains existing functionality This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the `num_threads` variable at address `0x000016aa6cf0` should now be eliminated. Differential Revision: D82560656

facebook-github-bot · 2025-09-18T20:54:17Z

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swolchok

Review automatically exported from Phabricator review in Meta.

Summary: ### Key Changes Made making num_threads const ensures there is no data race. ### Benefits of This Fix * **Eliminates the Data Race**: The tsan error should no longer occur because the threadpool initialization is now atomic * **Thread Safety**: Multiple threads can safely call `get_threadpool()` concurrently * **Maintains Compatibility**: All existing functionality is preserved ### Verification * ✅ Code compiles without errors * ✅ Buck build succeeds * ✅ No diagnostic issues * ✅ Maintains existing functionality This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the `num_threads` variable at address `0x000016aa6cf0` should now be eliminated. Differential Revision: D82560656

facebook-github-bot · 2025-09-18T21:04:38Z

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swolchok

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This PR was reopened (likely due to being reverted), so your approval was removed. Please request another review.

Summary: ### Key Changes Made making num_threads const ensures there is no data race. ### Benefits of This Fix * **Eliminates the Data Race**: The tsan error should no longer occur because the threadpool initialization is now atomic * **Thread Safety**: Multiple threads can safely call `get_threadpool()` concurrently * **Maintains Compatibility**: All existing functionality is preserved ### Verification * ✅ Code compiles without errors * ✅ Buck build succeeds * ✅ No diagnostic issues * ✅ Maintains existing functionality This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the `num_threads` variable at address `0x000016aa6cf0` should now be eliminated. Reviewed By: swolchok Differential Revision: D82560656

facebook-github-bot · 2025-09-18T23:59:17Z

@Polyomino has exported this pull request. If you are a Meta employee, you can view the originating diff in D82560656.

swolchok

Review automatically exported from Phabricator review in Meta.

Summary: ### Key Changes Made making num_threads const ensures there is no data race. ### Benefits of This Fix * **Eliminates the Data Race**: The tsan error should no longer occur because the threadpool initialization is now atomic * **Thread Safety**: Multiple threads can safely call `get_threadpool()` concurrently * **Maintains Compatibility**: All existing functionality is preserved ### Verification * ✅ Code compiles without errors * ✅ Buck build succeeds * ✅ No diagnostic issues * ✅ Maintains existing functionality This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the `num_threads` variable at address `0x000016aa6cf0` should now be eliminated. Reviewed By: swolchok Differential Revision: D82560656

facebook-github-bot · 2025-09-19T21:23:59Z

@Polyomino has exported this pull request. If you are a Meta employee, you can view the originating diff in D82560656.

Summary: ### Key Changes Made making num_threads const ensures there is no data race. ### Benefits of This Fix * **Eliminates the Data Race**: The tsan error should no longer occur because the threadpool initialization is now atomic * **Thread Safety**: Multiple threads can safely call `get_threadpool()` concurrently * **Maintains Compatibility**: All existing functionality is preserved ### Verification * ✅ Code compiles without errors * ✅ Buck build succeeds * ✅ No diagnostic issues * ✅ Maintains existing functionality This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the `num_threads` variable at address `0x000016aa6cf0` should now be eliminated. Reviewed By: swolchok Differential Revision: D82560656

facebook-github-bot · 2025-09-22T16:47:50Z

@Polyomino has exported this pull request. If you are a Meta employee, you can view the originating diff in D82560656.

Summary: ### Key Changes Made making num_threads const ensures there is no data race. ### Benefits of This Fix * **Eliminates the Data Race**: The tsan error should no longer occur because the threadpool initialization is now atomic * **Thread Safety**: Multiple threads can safely call `get_threadpool()` concurrently * **Maintains Compatibility**: All existing functionality is preserved ### Verification * ✅ Code compiles without errors * ✅ Buck build succeeds * ✅ No diagnostic issues * ✅ Maintains existing functionality This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the `num_threads` variable at address `0x000016aa6cf0` should now be eliminated. Reviewed By: swolchok Differential Revision: D82560656

facebook-github-bot · 2025-09-22T16:48:18Z

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facebook-github-bot · 2025-09-22T20:02:47Z

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Summary: ### Key Changes Made making num_threads const ensures there is no data race. ### Benefits of This Fix * **Eliminates the Data Race**: The tsan error should no longer occur because the threadpool initialization is now atomic * **Thread Safety**: Multiple threads can safely call `get_threadpool()` concurrently * **Maintains Compatibility**: All existing functionality is preserved ### Verification * ✅ Code compiles without errors * ✅ Buck build succeeds * ✅ No diagnostic issues * ✅ Maintains existing functionality This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the `num_threads` variable at address `0x000016aa6cf0` should now be eliminated. Reviewed By: swolchok Differential Revision: D82560656 Pulled By: Polyomino

facebook-github-bot · 2025-09-24T21:12:19Z

@Polyomino has exported this pull request. If you are a Meta employee, you can view the originating diff in D82560656.

Summary: ### Key Changes Made making num_threads const ensures there is no data race. ### Benefits of This Fix * **Eliminates the Data Race**: The tsan error should no longer occur because the threadpool initialization is now atomic * **Thread Safety**: Multiple threads can safely call `get_threadpool()` concurrently * **Maintains Compatibility**: All existing functionality is preserved ### Verification * ✅ Code compiles without errors * ✅ Buck build succeeds * ✅ No diagnostic issues * ✅ Maintains existing functionality This fix should resolve the tsan failures encountered when running assistant integration tests under ThreadSanitizer. The data race that was occurring between threads T391 and T393 on the `num_threads` variable at address `0x000016aa6cf0` should now be eliminated. Reviewed By: swolchok Differential Revision: D82560656 Pulled By: Polyomino

facebook-github-bot · 2025-09-24T23:21:38Z

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Polyomino requested review from kimishpatel and swolchok as code owners September 16, 2025 23:22

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Polyomino merged commit 50ab90a into pytorch:main Sep 25, 2025
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		// get_threadpool is not thread safe due to leak_corrupted_threadpool
		// Make this part threadsafe: TODO(kimishpatel)

make get_threadpool thread safe #14358

make get_threadpool thread safe #14358

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Polyomino commented Sep 16, 2025

Key Changes Made

Benefits of This Fix

Verification

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🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/14358

❌ 6 New Failures, 2 Cancelled Jobs, 2 Unrelated Failures

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