gh-87135: Hang non-main threads that attempt to acquire the GIL during finalization (GH-105805)

Instead of surprise crashes and memory corruption, we now hang threads that attempt to re-enter the Python interpreter after Python runtime finalization has started. These are typically daemon threads (our long standing mis-feature) but could also be threads spawned by extension modules that then try to call into Python. This marks the `PyThread_exit_thread` public C API as deprecated as there is no plausible safe way to accomplish that on any supported platform in the face of things like C++ code with finalizers anywhere on a thread's stack. Doing this was the least bad option.

Co-authored-by: Gregory P. Smith <greg@krypto.org>
This commit is contained in:
Jeremy Maitin-Shepard 2024-10-02 09:17:49 -07:00 committed by GitHub
parent 113b2d7583
commit 8cc5aa47ee
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10 changed files with 247 additions and 29 deletions

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@ -291,6 +291,14 @@ PyThread_exit_thread(void)
_endthreadex(0);
}
void _Py_NO_RETURN
PyThread_hang_thread(void)
{
while (1) {
SleepEx(INFINITE, TRUE);
}
}
/*
* Lock support. It has to be implemented as semaphores.
* I [Dag] tried to implement it with mutex but I could find a way to