From: John Snow Date: Fri, 25 Feb 2022 20:59:47 +0000 (-0500) Subject: python/aqmp: fix race condition in legacy.py X-Git-Tag: qemu-xen-4.17.0-rc4~63^2~2 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=673856f9d889dc50b6a1a7964df960c4f00c7c93;p=qemu-xen.git python/aqmp: fix race condition in legacy.py legacy.py provides a synchronous model. iotests frequently uses this paradigm: - create QMP client object - start QEMU process - await connection from QEMU process In the switch from sync to async QMP, the QMP client object stopped calling bind() and listen() during the QMP object creation step, which creates a race condition if the QEMU process dials in too quickly. With refactoring out of the way, restore the former behavior of calling bind() and listen() during __init__() to fix this race condition. Signed-off-by: John Snow Acked-by: Kevin Wolf Reviewed-by: Daniel P. Berrangé Message-id: 20220225205948.3693480-10-jsnow@redhat.com [Expanded commit message. --js] Signed-off-by: John Snow --- diff --git a/python/qemu/aqmp/legacy.py b/python/qemu/aqmp/legacy.py index dca1e76ed4..cb50e60564 100644 --- a/python/qemu/aqmp/legacy.py +++ b/python/qemu/aqmp/legacy.py @@ -57,7 +57,7 @@ class QEMUMonitorProtocol(qemu.qmp.QEMUMonitorProtocol): self._timeout: Optional[float] = None if server: - self._aqmp._bind_hack(address) # pylint: disable=protected-access + self._sync(self._aqmp.start_server(address)) _T = TypeVar('_T') @@ -90,10 +90,7 @@ class QEMUMonitorProtocol(qemu.qmp.QEMUMonitorProtocol): self._aqmp.await_greeting = True self._aqmp.negotiate = True - self._sync( - self._aqmp.start_server_and_accept(self._address), - timeout - ) + self._sync(self._aqmp.accept(), timeout) ret = self._get_greeting() assert ret is not None