AIX maps the first page of memory at address zero as valid, read-only. Reading
NULL is not a fault on AIX. This is utilized by IBM compiler optimizations.
One speculatively can indirect through a pointer which may be null without
first testing if null and defer the test before using the value.
faulthandler requires the importlib if "-X faulthandler" option is present on
the command line, so initialize faulthandler after importlib.
Add also an unit test.
* Set the default value of all_threads arguments to True
* Py_FatalError() dumps all threads, instead of only the current thread
Dump only the current thread is not reliable. In some cases, Python is unable
to retrieve the state of the current thread and so is unable to dump the
traceback. faulthandler keeps a reference to the interpreter and so is always
able to dump the traceback of all threads.
* Write a new test to ensure that dump_tracebacks_later() still works if
it was already called and then cancelled before
* Don't use a variable to check the status of the thread, only rely on locks
* The thread only releases cancel_event if it was able to acquire it (if
the timer was interrupted)
* The main thread always hold this lock. It is only released when
faulthandler_thread() is interrupted until this thread exits, or at Python
exit.
time.time() and/or time.sleep() are not accurate on Windows, don't test them
in test_faulthandler. Anyway, the check was written for an old implementation
of dump_tracebacks_later(), it is not more needed.
The traceback may contain "_is_owned":
Thread 0x40962b90:
File "/srv/buildbot/buildarea/3.x.bolen-ubuntu/build/Lib/threading.py", line 220 in _is_owned
File "/srv/buildbot/buildarea/3.x.bolen-ubuntu/build/Lib/threading.py", line 227 in wait
File "/srv/buildbot/buildarea/3.x.bolen-ubuntu/build/Lib/threading.py", line 421 in wait
File "<string>", line 23 in run
File "/srv/buildbot/buildarea/3.x.bolen-ubuntu/build/Lib/threading.py", line 735 in _bootstrap_inner
File "/srv/buildbot/buildarea/3.x.bolen-ubuntu/build/Lib/threading.py", line 708 in _bootstrap
Current thread XXX:
File "<string>", line 10 in dump
File "<string>", line 28 in <module>
* faulthandler_user() displays the tracebacks of all threads even if it is
unable to get the state of the current thread
* test_faulthandler: only release the GIL in test_gil_released() check
* create check_signum() subfunction
