[3.12] gh-125451: Fix deadlock in ProcessPoolExecutor shutdown (GH-125492) #125599
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…ythonGH-125492) There was a deadlock when `ProcessPoolExecutor` shuts down at the same time that a queueing thread handles an error processing a task. Don't use `_shutdown_lock` to protect the `_ThreadWakeup` pipes -- use an internal lock instead. This fixes the ordering deadlock where the `ExecutorManagerThread` holds the `_shutdown_lock` and joins the queueing thread, while the queueing thread is attempting to acquire the `_shutdown_lock` while closing the `_ThreadWakeup`. (cherry picked from commit 760872e) Co-authored-by: Sam Gross <colesbury@gmail.com>
This was referenced Oct 16, 2024
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There was a deadlock when
ProcessPoolExecutorshuts down at the same time that a queueing thread handles an error processing a task.Don't use
_shutdown_lockto protect the_ThreadWakeuppipes -- use an internal lock instead. This fixes the ordering deadlock where theExecutorManagerThreadholds the_shutdown_lockand joins the queueing thread, while the queueing thread is attempting to acquire the_shutdown_lockwhile closing the_ThreadWakeup.(cherry picked from commit 760872e)