From nobody Sun Feb 8 10:36:56 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1518624955828526.0598703872944; Wed, 14 Feb 2018 08:15:55 -0800 (PST) Received: from localhost ([::1]:35789 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1elzis-0000is-Uf for importer@patchew.org; Wed, 14 Feb 2018 11:15:55 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44251) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1elzcs-00047Y-8l for qemu-devel@nongnu.org; Wed, 14 Feb 2018 11:09:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1elzco-0008G2-98 for qemu-devel@nongnu.org; Wed, 14 Feb 2018 11:09:42 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:46906 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1elzco-0008FU-4T for qemu-devel@nongnu.org; Wed, 14 Feb 2018 11:09:38 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4A29D40201A0 for ; Wed, 14 Feb 2018 16:09:37 +0000 (UTC) Received: from thh440s.redhat.com (ovpn-116-136.ams2.redhat.com [10.36.116.136]) by smtp.corp.redhat.com (Postfix) with ESMTP id DA87B2024CA4; Wed, 14 Feb 2018 16:09:35 +0000 (UTC) From: Thomas Huth To: qemu-devel@nongnu.org, =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Wed, 14 Feb 2018 17:09:35 +0100 Message-Id: <1518624575-7048-1-git-send-email-thuth@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Wed, 14 Feb 2018 16:09:37 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Wed, 14 Feb 2018 16:09:37 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'thuth@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH] io/channel-command: Do not kill the child process after closing the pipe X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?UTF-8?q?Luk=C3=A1=C5=A1=20Doktor?= , "Dr. David Alan Gilbert" , Juan Quintela Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" We are currently facing some migration failure on s390x when running certain avocado-vt tests, e.g. when running the test type_specific.io-github-autotest-qemu.migrate.with_reboot.exec.gzip_exec. This test is using 'migrate -d "exec:nc localhost 5200"' for the migration. The problem is detected at the receiving side, where the migration stream apparently ends too early. However, the cause for the problem is at the sending side: After writing the migration stream into the pipe to netcat, the source QEMU calls qio_channel_command_close() which closes the pipe and immediately (!) kills the child process afterwards (via the function qio_channel_command_abort()). So if the sending netcat did not read the final bytes from the pipe yet, or if it did not manage to send out all its buffers yet, it is killed before the whole migration stream is passed to the destination side. QEMU can not know how much time is required by the child process to send over all migration data, so we should not kill it, neither directly nor after a delay. Let's simply wait for the child process to exit gracefully instead (this was also the behaviour of pclose() that was used in "exec:" migration before the QIOChannel rework). Signed-off-by: Thomas Huth Reviewed-by: Daniel P. Berrang=C3=A9 --- io/channel-command.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/io/channel-command.c b/io/channel-command.c index 319c5ed..3e7eb17 100644 --- a/io/channel-command.c +++ b/io/channel-command.c @@ -301,6 +301,9 @@ static int qio_channel_command_close(QIOChannel *ioc, { QIOChannelCommand *cioc =3D QIO_CHANNEL_COMMAND(ioc); int rv =3D 0; +#ifndef WIN32 + pid_t wp; +#endif =20 /* We close FDs before killing, because that * gives a better chance of clean shutdown @@ -315,11 +318,18 @@ static int qio_channel_command_close(QIOChannel *ioc, rv =3D -1; } cioc->writefd =3D cioc->readfd =3D -1; + #ifndef WIN32 - if (qio_channel_command_abort(cioc, errp) < 0) { + do { + wp =3D waitpid(cioc->pid, NULL, 0); + } while (wp =3D=3D (pid_t)-1 && errno =3D=3D EINTR); + if (wp =3D=3D (pid_t)-1) { + error_setg_errno(errp, errno, "Failed to wait for pid %llu", + (unsigned long long)cioc->pid); return -1; } #endif + if (rv < 0) { error_setg_errno(errp, errno, "%s", "Unable to close command"); --=20 1.8.3.1