gh-102512: Fix threading after os.fork() called from a foreign thread #113261
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If os.fork() is called from a DummyThread (a thread started not by the threading module, in which somebody called threading.current_thread()), it becomes main thread. Threading shutdown logic relies on the main thread having tstate_lock, so initialize it for the DummyThread too. Fixes python#102512
vstinner
reviewed
Jan 10, 2024
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Thank you for your review Victor. I added more output in tests and added a test for foreign thread without DummyThread. The code was significantly rewritten. Replacing a DummyThread with a MainThread leaves a DummyThread thread with the same ident (this is disturbing) in |
vstinner
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Jan 16, 2024
Misc/NEWS.d/next/Library/2023-03-08-00-02-30.gh-issue-102512.LiugDr.rst
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serhiy-storchaka
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needs backport to 3.11
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Thanks @serhiy-storchaka for the PR 🌮🎉.. I'm working now to backport this PR to: 3.11. |
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Thanks @serhiy-storchaka for the PR 🌮🎉.. I'm working now to backport this PR to: 3.12. |
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Sorry, @serhiy-storchaka, I could not cleanly backport this to |
miss-islington
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Jan 22, 2024
…alled from a foreign thread (pythonGH-113261) Always set a _MainThread as a main thread after os.fork() is called from a thread started not by the threading module. A new _MainThread was already set as a new main thread after fork if threading.current_thread() was not called for a foreign thread before fork. Now, if it was called before fork, the implicitly created _DummyThread will be turned into _MainThread after fork. It fixes, in particularly, an incompatibility of _DummyThread with the threading shutdown logic which relies on the main thread having tstate_lock. (cherry picked from commit 49785b0) Co-authored-by: Serhiy Storchaka <[email protected]> Co-authored-by: Marek Marczykowski-Górecki <[email protected]>
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GH-114430 is a backport of this pull request to the 3.12 branch. |
serhiy-storchaka
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Jan 22, 2024
…ork() called from a foreign thread (pythonGH-113261) Always set a _MainThread as a main thread after os.fork() is called from a thread started not by the threading module. A new _MainThread was already set as a new main thread after fork if threading.current_thread() was not called for a foreign thread before fork. Now, if it was called before fork, the implicitly created _DummyThread will be turned into _MainThread after fork. It fixes, in particularly, an incompatibility of _DummyThread with the threading shutdown logic which relies on the main thread having tstate_lock. (cherry picked from commit 49785b0) Co-authored-by: Marek Marczykowski-Górecki <[email protected]>
serhiy-storchaka
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Jan 22, 2024
…ork() called from a foreign thread (pythonGH-113261) Always set a _MainThread as a main thread after os.fork() is called from a thread started not by the threading module. A new _MainThread was already set as a new main thread after fork if threading.current_thread() was not called for a foreign thread before fork. Now, if it was called before fork, the implicitly created _DummyThread will be turned into _MainThread after fork. It fixes, in particularly, an incompatibility of _DummyThread with the threading shutdown logic which relies on the main thread having tstate_lock. (cherry picked from commit 49785b0) Co-authored-by: Serhiy Storchaka <[email protected]> Co-authored-by: Marek Marczykowski-Górecki <[email protected]>
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GH-114431 is a backport of this pull request to the 3.11 branch. |
serhiy-storchaka
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Jan 22, 2024
…called from a foreign thread (GH-113261) (GH-114431) Always set a _MainThread as a main thread after os.fork() is called from a thread started not by the threading module. A new _MainThread was already set as a new main thread after fork if threading.current_thread() was not called for a foreign thread before fork. Now, if it was called before fork, the implicitly created _DummyThread will be turned into _MainThread after fork. It fixes, in particularly, an incompatibility of _DummyThread with the threading shutdown logic which relies on the main thread having tstate_lock. (cherry picked from commit 49785b0) Co-authored-by: Marek Marczykowski-Górecki <[email protected]>
serhiy-storchaka
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Jan 22, 2024
…alled from a foreign thread (pythonGH-113261) Always set a _MainThread as a main thread after os.fork() is called from a thread started not by the threading module. A new _MainThread was already set as a new main thread after fork if threading.current_thread() was not called for a foreign thread before fork. Now, if it was called before fork, the implicitly created _DummyThread will be turned into _MainThread after fork. It fixes, in particularly, an incompatibility of _DummyThread with the threading shutdown logic which relies on the main thread having tstate_lock. (cherry picked from commit 49785b0) Co-authored-by: Serhiy Storchaka <[email protected]> Co-authored-by: Marek Marczykowski-Górecki <[email protected]>
serhiy-storchaka
added a commit
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Jan 22, 2024
…called from a foreign thread (GH-113261) (GH-114430) Always set a _MainThread as a main thread after os.fork() is called from a thread started not by the threading module. A new _MainThread was already set as a new main thread after fork if threading.current_thread() was not called for a foreign thread before fork. Now, if it was called before fork, the implicitly created _DummyThread will be turned into _MainThread after fork. It fixes, in particularly, an incompatibility of _DummyThread with the threading shutdown logic which relies on the main thread having tstate_lock. (cherry picked from commit 49785b0) Co-authored-by: Serhiy Storchaka <[email protected]> Co-authored-by: Marek Marczykowski-Górecki <[email protected]>
aisk
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Feb 11, 2024
…alled from a foreign thread (pythonGH-113261) Always set a _MainThread as a main thread after os.fork() is called from a thread started not by the threading module. A new _MainThread was already set as a new main thread after fork if threading.current_thread() was not called for a foreign thread before fork. Now, if it was called before fork, the implicitly created _DummyThread will be turned into _MainThread after fork. It fixes, in particularly, an incompatibility of _DummyThread with the threading shutdown logic which relies on the main thread having tstate_lock. Co-authored-by: Marek Marczykowski-Górecki <[email protected]>
Glyphack
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Sep 2, 2024
…alled from a foreign thread (pythonGH-113261) Always set a _MainThread as a main thread after os.fork() is called from a thread started not by the threading module. A new _MainThread was already set as a new main thread after fork if threading.current_thread() was not called for a foreign thread before fork. Now, if it was called before fork, the implicitly created _DummyThread will be turned into _MainThread after fork. It fixes, in particularly, an incompatibility of _DummyThread with the threading shutdown logic which relies on the main thread having tstate_lock. Co-authored-by: Marek Marczykowski-Górecki <[email protected]>
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Based on #102517. It recreates a
_DummyThreadas_MainThreadafter fork.os.fork()called from DummyThread confuses threading shutdown logic #102512