* [3.6] bpo-30703: Improve signal delivery (GH-2415)
* Improve signal delivery
Avoid using Py_AddPendingCall from signal handler, to avoid calling signal-unsafe functions.
* Remove unused function
* Improve comments
* Add stress test
* Adapt for --without-threads
* Add second stress test
* Add NEWS blurb
* Address comments @haypo.
(cherry picked from commit c08177a1cc)
* bpo-30796: Fix failures in signal delivery stress test (#2488)
* bpo-30796: Fix failures in signal delivery stress test
setitimer() can have a poor minimum resolution on some machines,
this would make the test reach its deadline (and a stray signal
could then kill a subsequent test).
* Make sure to clear the itimer after the test
* Add Lib/test/signalinterproctester.py
* Don't disable the garbage collector anymore
* Don't use os.fork() with a subprocess to not inherit existing signal handlers
or threads: start from a fresh process
* Don't use UNIX kill command to send a signal but Python os.kill()
* Use a timeout of 10 seconds to wait for the signal instead of 1 second
* Always use signal.pause(), instead of time.wait(1), to wait for a signal
* Use context manager on subprocess.Popen
* remove code to retry on EINTR: it's no more needed since the PEP 475
* remove unused function exit_subprocess()
* Cleanup the code
I have compared output between pre- and post-patch runs of these tests
to make sure there's nothing missing and nothing broken, on both
Windows and Linux. The only differences I found were actually tests
that were previously *not* run.
when interrupted by a signal not in the *sigset* parameter, if the signal
handler does not raise an exception. signal.sigtimedwait() recomputes the
timeout with a monotonic clock when it is retried.
Remove test_signal.test_sigwaitinfo_interrupted() because sigwaitinfo() doesn't
raise InterruptedError anymore if it is interrupted by a signal not in its
sigset parameter.
retried with the recomputed delay, except if the signal handler raises an
exception (PEP 475).
Modify also test_signal to use a monotonic clock instead of the system clock.
- Use _testcapi.raise_signal() in test_signal
- close also os.pipe() file descriptors in some test_signal tests where they
were not closed properly
- Remove faulthandler._sigill() and faulthandler._sigbus(): reuse
_testcapi.raise_signal() in test_faulthandler
When signals are unblocked, pending signal ared delivered in the reverse order
of their number (also on Linux, not only on FreeBSD 6).
Don't sort signals by their number if signals were not blocked (test_signum).
* Don't create a thread at startup anymore to initialize the pthread library:
it changes the behaviour of many functions related to signal handling like
sigwait()
* Reenable test_sigtimedwait_poll() on FreeBSD 6
Antoine Pitrou
Victor Stinner
Berker Peksag
Zachary Ware
Charles-François Natali
Antoine Pitrou
Stefan Krah
Giampaolo Rodola'
R David Murray
Nick Coghlan
Benjamin Peterson
Andrew Svetlov
Christian Heimes
Jesus Cea
Charles-François Natali
Victor Stinner