From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DEA8BC433EF for ; Tue, 26 Oct 2021 18:01:52 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 90C296109D for ; Tue, 26 Oct 2021 18:01:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 90C296109D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:45268 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mfQli-0001hb-Gx for qemu-devel@archiver.kernel.org; Tue, 26 Oct 2021 14:01:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51420) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mfQgS-0003Zg-VA for qemu-devel@nongnu.org; Tue, 26 Oct 2021 13:56:26 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:52893) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mfQgO-0004Xl-2K for qemu-devel@nongnu.org; Tue, 26 Oct 2021 13:56:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635270979; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aNr6SNMc0oBTtifDVANAHZqAY+Pl5cwKRo2yK0XeY90=; b=KE9o5TCsMiGXgNCU7boZP5SrdrwgPksB3Z4W5yg1N4TqoCrROU9QA7L4/BEorLHBxaXMne JeW45JexcGtfS+Wq4bN4wdoTAc7NawtFz7l1YfB/CMA9xnjUmnlZW8lvCG1LbIkCu5y/Da xMyy8oj4XilYChXk4/vP3LqkE+Me6jc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-18-L-0dErxBP3q9ckrREMJLHA-1; Tue, 26 Oct 2021 13:56:16 -0400 X-MC-Unique: L-0dErxBP3q9ckrREMJLHA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 87D6110247A7; Tue, 26 Oct 2021 17:56:15 +0000 (UTC) Received: from scv.redhat.com (unknown [10.22.17.51]) by smtp.corp.redhat.com (Postfix) with ESMTP id BBF805DF21; Tue, 26 Oct 2021 17:56:14 +0000 (UTC) From: John Snow To: qemu-devel@nongnu.org Subject: [PATCH v5 2/8] python/machine: Handle QMP errors on close more meticulously Date: Tue, 26 Oct 2021 13:56:06 -0400 Message-Id: <20211026175612.4127598-3-jsnow@redhat.com> In-Reply-To: <20211026175612.4127598-1-jsnow@redhat.com> References: <20211026175612.4127598-1-jsnow@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jsnow@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=170.10.133.124; envelope-from=jsnow@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , Eduardo Habkost , qemu-block@nongnu.org, Hanna Reitz , Cleber Rosa , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" To use the AQMP backend, Machine just needs to be a little more diligent about what happens when closing a QMP connection. The operation is no longer a freebie in the async world; it may return errors encountered in the async bottom half on incoming message receipt, etc. (AQMP's disconnect, ultimately, serves as the quiescence point where all async contexts are gathered together, and any final errors reported at that point.) Because async QMP continues to check for messages asynchronously, it's almost certainly likely that the loop will have exited due to EOF after issuing the last 'quit' command. That error will ultimately be bubbled up when attempting to close the QMP connection. The manager class here then is free to discard it -- if it was expected. Signed-off-by: John Snow Reviewed-by: Hanna Reitz --- python/qemu/machine/machine.py | 48 +++++++++++++++++++++++++++++----- 1 file changed, 42 insertions(+), 6 deletions(-) diff --git a/python/qemu/machine/machine.py b/python/qemu/machine/machine.py index 0bd40bc2f76..a0cf69786b4 100644 --- a/python/qemu/machine/machine.py +++ b/python/qemu/machine/machine.py @@ -342,9 +342,15 @@ def _post_shutdown(self) -> None: # Comprehensive reset for the failed launch case: self._early_cleanup() - if self._qmp_connection: - self._qmp.close() - self._qmp_connection = None + try: + self._close_qmp_connection() + except Exception as err: # pylint: disable=broad-except + LOG.warning( + "Exception closing QMP connection: %s", + str(err) if str(err) else type(err).__name__ + ) + finally: + assert self._qmp_connection is None self._close_qemu_log_file() @@ -420,6 +426,31 @@ def _launch(self) -> None: close_fds=False) self._post_launch() + def _close_qmp_connection(self) -> None: + """ + Close the underlying QMP connection, if any. + + Dutifully report errors that occurred while closing, but assume + that any error encountered indicates an abnormal termination + process and not a failure to close. + """ + if self._qmp_connection is None: + return + + try: + self._qmp.close() + except EOFError: + # EOF can occur as an Exception here when using the Async + # QMP backend. It indicates that the server closed the + # stream. If we successfully issued 'quit' at any point, + # then this was expected. If the remote went away without + # our permission, it's worth reporting that as an abnormal + # shutdown case. + if not (self._user_killed or self._quit_issued): + raise + finally: + self._qmp_connection = None + def _early_cleanup(self) -> None: """ Perform any cleanup that needs to happen before the VM exits. @@ -460,9 +491,14 @@ def _soft_shutdown(self, timeout: Optional[int]) -> None: self._early_cleanup() if self._qmp_connection: - if not self._quit_issued: - # Might raise ConnectionReset - self.qmp('quit') + try: + if not self._quit_issued: + # May raise ExecInterruptedError or StateError if the + # connection dies or has *already* died. + self.qmp('quit') + finally: + # Regardless, we want to quiesce the connection. + self._close_qmp_connection() # May raise subprocess.TimeoutExpired self._subp.wait(timeout=timeout) -- 2.31.1