From patchwork Fri Dec 15 11:51:23 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 849130 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3yypgn04K4z9t2W for ; Fri, 15 Dec 2017 22:52:02 +1100 (AEDT) Received: from localhost ([::1]:45852 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ePoWz-000575-8C for incoming@patchwork.ozlabs.org; Fri, 15 Dec 2017 06:51:57 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38101) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ePoWa-00054m-Jb for qemu-devel@nongnu.org; Fri, 15 Dec 2017 06:51:33 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ePoWX-00010W-FG for qemu-devel@nongnu.org; Fri, 15 Dec 2017 06:51:32 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60876) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ePoWX-0000w0-94 for qemu-devel@nongnu.org; Fri, 15 Dec 2017 06:51:29 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0658481DF0 for ; Fri, 15 Dec 2017 11:51:28 +0000 (UTC) Received: from dgilbert-t530.redhat.com (ovpn-117-102.ams2.redhat.com [10.36.117.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id DE52B63136; Fri, 15 Dec 2017 11:51:24 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, quintela@redhat.com Date: Fri, 15 Dec 2017 11:51:23 +0000 Message-Id: <20171215115123.12959-1-dgilbert@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Fri, 15 Dec 2017 11:51:28 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] migration: Guard ram_bytes_remaining against early call 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: peterx@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: "Dr. David Alan Gilbert" Calling ram_bytes_remaining during the early part of setup is unsafe because the ram_state isn't yet initialised. This can happen in the sequence: migrate migrate_cancel info migrate if the migrate sticks trying to connect (e.g. to an unresponsive destination due to the connect timeout). Here 'info migrate' sees a state of CANCELLING and so assumes the migrate has partially happened. partial fix for: RH bz: https://bugzilla.redhat.com/show_bug.cgi?id=1525899 Reported-by: Xianxian Wang Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Peter Xu Reviewed-by: Juan Quintela --- migration/ram.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/migration/ram.c b/migration/ram.c index 021d583b9b..cb1950f3eb 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -237,7 +237,8 @@ static RAMState *ram_state; uint64_t ram_bytes_remaining(void) { - return ram_state->migration_dirty_pages * TARGET_PAGE_SIZE; + return ram_state ? (ram_state->migration_dirty_pages * TARGET_PAGE_SIZE) : + 0; } MigrationStats ram_counters;