From patchwork Mon Oct 16 06:51:45 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 826144 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 3yFpxz0hjhz9t1t for ; Mon, 16 Oct 2017 17:55:56 +1100 (AEDT) Received: from localhost ([::1]:59615 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e3zJa-0002bW-PD for incoming@patchwork.ozlabs.org; Mon, 16 Oct 2017 02:55:54 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42228) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e3zGK-0000Lh-58 for qemu-devel@nongnu.org; Mon, 16 Oct 2017 02:52:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e3zGI-00013l-R6 for qemu-devel@nongnu.org; Mon, 16 Oct 2017 02:52:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36722) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e3zGI-00012c-Il for qemu-devel@nongnu.org; Mon, 16 Oct 2017 02:52:30 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 75D3381DEB; Mon, 16 Oct 2017 06:52:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 75D3381DEB Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=peterx@redhat.com Received: from pxdev.xzpeter.org.com (dhcp-15-225.nay.redhat.com [10.66.15.225]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0840A62930; Mon, 16 Oct 2017 06:52:26 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Mon, 16 Oct 2017 14:51:45 +0800 Message-Id: <20171016065216.18162-2-peterx@redhat.com> In-Reply-To: <20171016065216.18162-1-peterx@redhat.com> References: <20171016065216.18162-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Mon, 16 Oct 2017 06:52:29 +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 v3 01/32] migration: better error handling with QEMUFile 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: Andrea Arcangeli , Juan Quintela , Alexey Perevalov , peterx@redhat.com, "Dr . David Alan Gilbert" Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" If the postcopy down due to some reason, we can always see this on dst: qemu-system-x86_64: RP: Received invalid message 0x0000 length 0x0000 However in most cases that's not the real issue. The problem is that qemu_get_be16() has no way to show whether the returned data is valid or not, and we are _always_ assuming it is valid. That's possibly not wise. The best approach to solve this would be: refactoring QEMUFile interface to allow the APIs to return error if there is. However it needs quite a bit of work and testing. For now, let's explicitly check the validity first before using the data in all places for qemu_get_*(). This patch tries to fix most of the cases I can see. Only if we are with this, can we make sure we are processing the valid data, and also can we make sure we can capture the channel down events correctly. Signed-off-by: Peter Xu --- migration/migration.c | 5 +++++ migration/ram.c | 26 ++++++++++++++++++++++---- migration/savevm.c | 40 ++++++++++++++++++++++++++++++++++++++-- 3 files changed, 65 insertions(+), 6 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index 157b4e4c7d..3366bdddcc 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1657,6 +1657,11 @@ static void *source_return_path_thread(void *opaque) header_type = qemu_get_be16(rp); header_len = qemu_get_be16(rp); + if (qemu_file_get_error(rp)) { + mark_source_rp_bad(ms); + goto out; + } + if (header_type >= MIG_RP_MSG_MAX || header_type == MIG_RP_MSG_INVALID) { error_report("RP: Received invalid message 0x%04x length 0x%04x", diff --git a/migration/ram.c b/migration/ram.c index c30db15d4c..85cb965a14 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -2622,7 +2622,7 @@ static int ram_load_postcopy(QEMUFile *f) void *last_host = NULL; bool all_zero = false; - while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) { + while (!(flags & RAM_SAVE_FLAG_EOS)) { ram_addr_t addr; void *host = NULL; void *page_buffer = NULL; @@ -2631,6 +2631,16 @@ static int ram_load_postcopy(QEMUFile *f) uint8_t ch; addr = qemu_get_be64(f); + + /* + * If qemu file error, we should stop here, and then "addr" + * may be invalid + */ + ret = qemu_file_get_error(f); + if (ret) { + break; + } + flags = addr & ~TARGET_PAGE_MASK; addr &= TARGET_PAGE_MASK; @@ -2711,6 +2721,13 @@ static int ram_load_postcopy(QEMUFile *f) error_report("Unknown combination of migration flags: %#x" " (postcopy mode)", flags); ret = -EINVAL; + break; + } + + /* Detect for any possible file errors */ + if (qemu_file_get_error(f)) { + ret = qemu_file_get_error(f); + break; } if (place_needed) { @@ -2724,9 +2741,10 @@ static int ram_load_postcopy(QEMUFile *f) ret = postcopy_place_page(mis, place_dest, place_source, block); } - } - if (!ret) { - ret = qemu_file_get_error(f); + + if (ret) { + break; + } } } diff --git a/migration/savevm.c b/migration/savevm.c index 4a88228614..1da0255cd7 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -1765,6 +1765,11 @@ static int loadvm_process_command(QEMUFile *f) cmd = qemu_get_be16(f); len = qemu_get_be16(f); + /* Check validity before continue processing of cmds */ + if (qemu_file_get_error(f)) { + return qemu_file_get_error(f); + } + trace_loadvm_process_command(cmd, len); if (cmd >= MIG_CMD_MAX || cmd == MIG_CMD_INVALID) { error_report("MIG_CMD 0x%x unknown (len 0x%x)", cmd, len); @@ -1830,6 +1835,7 @@ static int loadvm_process_command(QEMUFile *f) */ static bool check_section_footer(QEMUFile *f, SaveStateEntry *se) { + int ret; uint8_t read_mark; uint32_t read_section_id; @@ -1840,6 +1846,13 @@ static bool check_section_footer(QEMUFile *f, SaveStateEntry *se) read_mark = qemu_get_byte(f); + ret = qemu_file_get_error(f); + if (ret) { + error_report("%s: Read section footer failed: %d", + __func__, ret); + return false; + } + if (read_mark != QEMU_VM_SECTION_FOOTER) { error_report("Missing section footer for %s", se->idstr); return false; @@ -1875,6 +1888,13 @@ qemu_loadvm_section_start_full(QEMUFile *f, MigrationIncomingState *mis) instance_id = qemu_get_be32(f); version_id = qemu_get_be32(f); + ret = qemu_file_get_error(f); + if (ret) { + error_report("%s: Failed to read instance/version ID: %d", + __func__, ret); + return ret; + } + trace_qemu_loadvm_state_section_startfull(section_id, idstr, instance_id, version_id); /* Find savevm section */ @@ -1922,6 +1942,13 @@ qemu_loadvm_section_part_end(QEMUFile *f, MigrationIncomingState *mis) section_id = qemu_get_be32(f); + ret = qemu_file_get_error(f); + if (ret) { + error_report("%s: Failed to read section ID: %d", + __func__, ret); + return ret; + } + trace_qemu_loadvm_state_section_partend(section_id); QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->load_section_id == section_id) { @@ -1989,8 +2016,14 @@ static int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis) uint8_t section_type; int ret = 0; - while ((section_type = qemu_get_byte(f)) != QEMU_VM_EOF) { - ret = 0; + while (true) { + section_type = qemu_get_byte(f); + + if (qemu_file_get_error(f)) { + ret = qemu_file_get_error(f); + break; + } + trace_qemu_loadvm_state_section(section_type); switch (section_type) { case QEMU_VM_SECTION_START: @@ -2014,6 +2047,9 @@ static int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis) goto out; } break; + case QEMU_VM_EOF: + /* This is the end of migration */ + goto out; default: error_report("Unknown savevm section type %d", section_type); ret = -EINVAL;