xds: fix race condition in ext_proc client interceptor halfClose - #12948
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kannanjgithub merged 1 commit intoAug 5, 2026
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Fixes a race condition in ExternalProcessorClientInterceptor$DataPlaneClientCall.halfClose() that can cause the call to hang when the external processor stream completes concurrently. If the external processor stream completes (marking state as COMPLETED and setting passThroughMode to true) after halfClose() has already checked passThroughMode (seeing false), halfClose() would subsequently see the state as COMPLETED and return early without invoking proceedWithHalfClose(). This commit fixes the race by re-checking passThroughMode inside the isCompleted() block in halfClose(), ensuring we proceed with half-close if pass-through mode was enabled late.
sauravzg
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Aug 4, 2026
sauravzg
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We should add a test for this case if possible to reproduce.
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It is not, the window for race is tiny and it entirely depends on processor scheduling and preemptions, so it cannot reproduced at will via a test. |
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Fixes a race condition in
ExternalProcessorClientInterceptor$DataPlaneClientCall.halfClose()that can cause the call to hang when the external processor stream completes concurrently.If the external processor stream completes (marking state as COMPLETED and setting passThroughMode to true) after
halfClose()has already checkedpassThroughMode(seeing false), halfClose() would subsequently see the state as COMPLETED and return early without invokingproceedWithHalfClose().This commit fixes the race by re-checking passThroughMode inside the
isCompleted()block inhalfClose(), ensuring we proceed with half-close if pass-through mode was enabled late.