[release/8.0] Fix deadlock in EventPipeEventDispatcher #92912
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jeffschwMSFT
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Oct 3, 2023
lateralusX
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Oct 3, 2023
rbhanda
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CI failure is unrelated. Not sure why KnownBuildError did not link it: #92944 |
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Backport of #92806 to release/8.0
/cc @tommcdon @davmason
Customer Impact
Fixes a deadlock issue #92236 caught in CI.
Taking
m_dispatchControlLockaround the call toEventPipeInternal.Disableleads to a potential deadlock where one thread is holding theEventListenersLockand trying to getm_dispatchControlLockand the disable thread is holdingm_dispatchControlLockand trying to getEventListenersLockas part of handling the disable command.This switches to using volatile reads and writes (just for the observability part) to make the dispatch loop wait until
SignalSessionhas been called before calling in toDisableTesting
Validated eventpipe test no longer hangs
Risk
Low