On Tue, Sep 12, 2023 at 11:13:40PM +1000, Nicholas Piggin wrote: > Occasionally some avocado tests will fail waiting for console line > despite the machine running correctly. Console data goes missing, as can > be seen in the console log. This is due to _console_interaction calling > makefile() on the console socket each time it is invoked, which must be > losing old buffer contents when going out of scope. > > It is not enough to makefile() with buffered=0. That helps significantly > but data loss is still possible. My guess is that readline() has a line > buffer even when the file is in unbuffered mode, that can eat data. > > Fix this by providing a console file that persists for the life of the > console. > > Signed-off-by: Nicholas Piggin <[email protected]> > --- > > For some reason, ppc_prep_40p.py:IbmPrep40pMachine.test_openbios_192m > was flakey for me due to this bug. I don't know why that in particular, > 3 calls to wait_for_console_pattern probably helps. > > I didn't pinpoint when the bug was introduced because the original > was probably not buggy because it was only run once at the end of the > test. At some point after it was moved to common code, something would > have started to call it more than once which is where potential for bug > is introduced.
I'm suspecting this patch might also fix many other failures we see in avocado, all with wait_for_console_pattern in their trace https://gitlab.com/qemu-project/qemu/-/issues/1884 > python/qemu/machine/machine.py | 19 +++++++++++++++++++ > tests/avocado/avocado_qemu/__init__.py | 2 +- > 2 files changed, 20 insertions(+), 1 deletion(-) > > diff --git a/python/qemu/machine/machine.py b/python/qemu/machine/machine.py > index c16a0b6fed..35d5a672db 100644 > --- a/python/qemu/machine/machine.py > +++ b/python/qemu/machine/machine.py > @@ -191,6 +191,7 @@ def __init__(self, > self.sock_dir, f"{self._name}.con" > ) > self._console_socket: Optional[socket.socket] = None > + self._console_file: Optional[socket.SocketIO] = None > self._remove_files: List[str] = [] > self._user_killed = False > self._quit_issued = False > @@ -509,6 +510,11 @@ def _early_cleanup(self) -> None: > # If we keep the console socket open, we may deadlock waiting > # for QEMU to exit, while QEMU is waiting for the socket to > # become writable. > + if self._console_file is not None: > + LOG.debug("Closing console file") > + self._console_file.close() > + self._console_file = None > + > if self._console_socket is not None: > LOG.debug("Closing console socket") > self._console_socket.close() > @@ -874,12 +880,25 @@ def console_socket(self) -> socket.socket: > Returns a socket connected to the console > """ > if self._console_socket is None: > + LOG.debug("Opening console socket") > self._console_socket = console_socket.ConsoleSocket( > self._console_address, > file=self._console_log_path, > drain=self._drain_console) > return self._console_socket > > + @property > + def console_file(self) -> socket.SocketIO: > + """ > + Returns a file associated with the console socket > + """ > + if self._console_file is None: > + LOG.debug("Opening console file") > + self._console_file = self.console_socket.makefile(mode='rb', > + buffering=0, > + > encoding='utf-8') > + return self._console_file > + > @property > def temp_dir(self) -> str: > """ > diff --git a/tests/avocado/avocado_qemu/__init__.py > b/tests/avocado/avocado_qemu/__init__.py > index 33090903f1..0172a359b7 100644 > --- a/tests/avocado/avocado_qemu/__init__.py > +++ b/tests/avocado/avocado_qemu/__init__.py > @@ -137,7 +137,7 @@ def _console_interaction(test, success_message, > failure_message, > assert not keep_sending or send_string > if vm is None: > vm = test.vm > - console = vm.console_socket.makefile(mode='rb', encoding='utf-8') > + console = vm.console_file > console_logger = logging.getLogger('console') > while True: > if send_string: Reviewed-by: Daniel P. Berrangé <[email protected]> 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 :|
