Mercurial > cpython-lru_cache-weakref
diff Python/pystate.c @ 33711:664b18aa6fc1 legacy-trunk
PyGILState_Release(): If we need to delete the TLS entry for this thread,
that must be done under protection of the GIL, for reasons explained in
new comments.
| author | Tim Peters <tim.peters@gmail.com> |
|---|---|
| date | Sat, 09 Oct 2004 23:55:36 +0000 |
| parents | 4981ba54f43d |
| children | 517e4ec0df89 |
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--- a/Python/pystate.c Sat Oct 09 23:01:11 2004 +0000 +++ b/Python/pystate.c Sat Oct 09 23:55:36 2004 +0000 @@ -472,24 +472,31 @@ assert(tcur->gilstate_counter >= 0); /* illegal counter value */ /* If we are about to destroy this thread-state, we must - clear it while the lock is held, as destructors may run - */ + * clear it while the lock is held, as destructors may run. + * In addition, we have to delete out TLS entry, which is keyed + * by thread id, while the GIL is held: the thread calling us may + * go away, and a new thread may be created with the same thread + * id. If we don't delete our TLS until after the GIL is released, + * that new thread may manage to insert a TLS value with the same + * thread id as ours, and then we'd erroneously delete it. + */ if (tcur->gilstate_counter == 0) { /* can't have been locked when we created it */ assert(oldstate == PyGILState_UNLOCKED); PyThreadState_Clear(tcur); + /* Delete this thread from our TLS */ + PyThread_delete_key_value(autoTLSkey); } /* Release the lock if necessary */ if (oldstate == PyGILState_UNLOCKED) PyEval_ReleaseThread(tcur); - /* Now complete destruction of the thread if necessary */ - if (tcur->gilstate_counter == 0) { - /* Delete this thread from our TLS */ - PyThread_delete_key_value(autoTLSkey); - /* Delete the thread-state */ + /* Now complete destruction of the thread if necessary. This + * couldn't be done before PyEval_ReleaseThread() because + * PyThreadState_Delete doesn't allow deleting the current thread. + */ + if (tcur->gilstate_counter == 0) PyThreadState_Delete(tcur); - } } #endif /* WITH_THREAD */