On Fri, Mar 03, 2023 at 04:49:36PM +0100, Thomas Huth wrote: > On 03/03/2023 14.06, Daniel P. Berrangé wrote: > > On Fri, Mar 03, 2023 at 10:45:40AM +0000, Daniel P. Berrangé wrote: > > > On Fri, Mar 03, 2023 at 09:30:39AM +0100, Thomas Huth wrote: > > > > On 02/03/2023 19.46, Daniel P. Berrangé wrote: > > > > 3) When I tried this last year, I had a weird problem that > > > > the terminal sometimes gets messed up ... I wasn't able > > > > to track it down back then - could you check by running > > > > "make check-block" many times (>10 times) to see whether > > > > it happens with your series or not? > > > > > > I've just seen this - echo got disabled on my terminal. > > > > The problem is that testrunner.py script doing > > > > # We want to save current tty settings during test run, > > # since an aborting qemu call may leave things screwed up. > > @contextmanager > > def savetty() -> Iterator[None]: > > isterm = sys.stdin.isatty() > > if isterm: > > fd = sys.stdin.fileno() > > attr = termios.tcgetattr(fd) > > > > try: > > yield > > finally: > > if isterm: > > termios.tcsetattr(fd, termios.TCSADRAIN, attr) > > > > > > When invoking 'check' this wraps around execution of the entire > > 'check' script. IOW it saves/restores the terminal once. > > > > When we invoke 'check' in parallel it will save/restore the same > > terminal for each invokation. > > > > If the 'termios.tcgetattr' call runs at the same time as there is > > a QEMU running which has put the terminal in raw mode, then when > > 'check' exits it'll "restore" the terminal to raw mode. > > > > IOW, this savetty() logic is fundamentally unsafe when invoking > > 'check' in parallel. > > Hmm, couldn't we e.g. also simply skip this termios stuff when running with > "--tap" ?
It actually turns out to be way simpler. We merely need to set stdin=subprocess.DEVNULL. There is no valid reason for the test cases to be reading for stdin, as that would block execution. By setting stdin==/dev/null, the isatty(0) checks will fail and thus QEMU won't mess with termios, and thus we don't need any save/restore dance either. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
