Re: [Qemu-devel] 答复: Re: 答复: Re: 答复: Re: 答复: Re: [BUG]COLO failover hang

[Hailiang Zhang]

On 2017/3/22 16:09, address@hidden wrote:
> hi:
>
> yes.it is better.
>
> And should we delete

Yes, you are right.

> #ifdef WIN32
>
>      QIO_CHANNEL(cioc)-＞event = CreateEvent(NULL, FALSE, FALSE, NULL)
>
> #endif
>
>
>
>
> in qio_channel_socket_accept？
>
> qio_channel_socket_new already have it.
>
>
>
>
>
>
>
>
>
>
>
>
> 原始邮件
>
>
>
> 发件人： address@hidden
> 收件人：王广10165992
> 抄送人： address@hidden address@hidden address@hidden address@hidden
> 日 期 ：2017年03月22日 15:03
> 主 题 ：Re: [Qemu-devel]  答复: Re:  答复: Re: 答复: Re: [BUG]COLO failover hang
>
>
>
>
>
> Hi,
>
> On 2017/3/22 9:42, address@hidden wrote:
> ＞ diff --git a/migration/socket.c b/migration/socket.c
> ＞
> ＞
> ＞ index 13966f1..d65a0ea 100644
> ＞
> ＞
> ＞ --- a/migration/socket.c
> ＞
> ＞
> ＞ +++ b/migration/socket.c
> ＞
> ＞
> ＞ @@ -147,8 +147,9 @@ static gboolean 
> socket_accept_incoming_migration(QIOChannel *ioc,
> ＞
> ＞
> ＞       }
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞       trace_migration_socket_incoming_accepted()
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞       qio_channel_set_name(QIO_CHANNEL(sioc), "migration-socket-incoming")
> ＞
> ＞
> ＞ +    qio_channel_set_feature(QIO_CHANNEL(sioc), QIO_CHANNEL_FEATURE_SHUTDOWN)
> ＞
> ＞
> ＞       migration_channel_process_incoming(migrate_get_current(),
> ＞
> ＞
> ＞                                          QIO_CHANNEL(sioc))
> ＞
> ＞
> ＞       object_unref(OBJECT(sioc))
> ＞
> ＞
> ＞
> ＞
> ＞ Is this patch ok?
> ＞
>
> Yes, i think this works, but a better way maybe to call 
> qio_channel_set_feature()
> in qio_channel_socket_accept(), we didn't set the SHUTDOWN feature for the 
> socket accept fd,
> Or fix it by this:
>
> diff --git a/io/channel-socket.c b/io/channel-socket.c
> index f546c68..ce6894c 100644
> --- a/io/channel-socket.c
> +++ b/io/channel-socket.c
> @@ -330,9 +330,8 @@ qio_channel_socket_accept(QIOChannelSocket *ioc,
>                              Error **errp)
>    {
>        QIOChannelSocket *cioc
> -
> -    cioc = QIO_CHANNEL_SOCKET(object_new(TYPE_QIO_CHANNEL_SOCKET))
> -    cioc-＞fd = -1
> +
> +    cioc = qio_channel_socket_new()
>        cioc-＞remoteAddrLen = sizeof(ioc-＞remoteAddr)
>        cioc-＞localAddrLen = sizeof(ioc-＞localAddr)
>
>
> Thanks,
> Hailiang
>
> ＞ I have test it . The test could not hang any more.
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞ 原始邮件
> ＞
> ＞
> ＞
> ＞ 发件人： address@hidden
> ＞ 收件人： address@hidden address@hidden
> ＞ 抄送人： address@hidden address@hidden address@hidden
> ＞ 日 期 ：2017年03月22日 09:11
> ＞ 主 题 ：Re: [Qemu-devel]  答复: Re:  答复: Re: [BUG]COLO failover hang
> ＞
> ＞
> ＞
> ＞
> ＞
> ＞ On 2017/3/21 19:56, Dr. David Alan Gilbert wrote:
> ＞ ＞ * Hailiang Zhang (address@hidden) wrote:
> ＞ ＞＞ Hi,
> ＞ ＞＞
> ＞ ＞＞ Thanks for reporting this, and i confirmed it in my test, and it is a bug.
> ＞ ＞＞
> ＞ ＞＞ Though we tried to call qemu_file_shutdown() to shutdown the related fd, in
> ＞ ＞＞ case COLO thread/incoming thread is stuck in read/write() while do 
> failover,
> ＞ ＞＞ but it didn't take effect, because all the fd used by COLO (also migration)
> ＞ ＞＞ has been wrapped by qio channel, and it will not call the shutdown API if
> ＞ ＞＞ we didn't qio_channel_set_feature(QIO_CHANNEL(sioc), 
> QIO_CHANNEL_FEATURE_SHUTDOWN).
> ＞ ＞＞
> ＞ ＞＞ Cc: Dr. David Alan Gilbert address@hidden
> ＞ ＞＞
> ＞ ＞＞ I doubted migration cancel has the same problem, it may be stuck in write()
> ＞ ＞＞ if we tried to cancel migration.
> ＞ ＞＞
> ＞ ＞＞ void fd_start_outgoing_migration(MigrationState *s, const char *fdname, 
> Error **errp)
> ＞ ＞＞ {
> ＞ ＞＞      qio_channel_set_name(QIO_CHANNEL(ioc), "migration-fd-outgoing")
> ＞ ＞＞      migration_channel_connect(s, ioc, NULL)
> ＞ ＞＞      ... ...
> ＞ ＞＞ We didn't call qio_channel_set_feature(QIO_CHANNEL(sioc), 
> QIO_CHANNEL_FEATURE_SHUTDOWN) above,
> ＞ ＞＞ and the
> ＞ ＞＞ migrate_fd_cancel()
> ＞ ＞＞ {
> ＞ ＞＞   ... ...
> ＞ ＞＞      if (s-＞state == MIGRATION_STATUS_CANCELLING && f) {
> ＞ ＞＞          qemu_file_shutdown(f)  --＞ This will not take effect. No ?
> ＞ ＞＞      }
> ＞ ＞＞ }
> ＞ ＞
> ＞ ＞ (cc'd in Daniel Berrange).
> ＞ ＞ I see that we call qio_channel_set_feature(ioc, 
> QIO_CHANNEL_FEATURE_SHUTDOWN) at the
> ＞ ＞ top of qio_channel_socket_new  so I think that's safe isn't it?
> ＞ ＞
> ＞
> ＞ Hmm, you are right, this problem is only exist for the migration incoming fd, 
> thanks.
> ＞
> ＞ ＞ Dave
> ＞ ＞
> ＞ ＞＞ Thanks,
> ＞ ＞＞ Hailiang
> ＞ ＞＞
> ＞ ＞＞ On 2017/3/21 16:10, address@hidden wrote:
> ＞ ＞＞＞ Thank you。
> ＞ ＞＞＞
> ＞ ＞＞＞ I have test aready。
> ＞ ＞＞＞
> ＞ ＞＞＞ When the Primary Node panic,the Secondary Node qemu hang at the same 
> place。
> ＞ ＞＞＞
> ＞ ＞＞＞ Incorrding http://wiki.qemu-project.org/Features/COLO ，kill Primary Node 
> qemu will not produce the problem,but Primary Node panic can。
> ＞ ＞＞＞
> ＞ ＞＞＞ I think due to the feature of channel does not support 
> QIO_CHANNEL_FEATURE_SHUTDOWN.
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ when failover,channel_shutdown could not shut down the channel.
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ so the colo_process_incoming_thread will hang at recvmsg.
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ I test a patch:
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ diff --git a/migration/socket.c b/migration/socket.c
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ index 13966f1..d65a0ea 100644
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ --- a/migration/socket.c
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ +++ b/migration/socket.c
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ @@ -147,8 +147,9 @@ static gboolean 
> socket_accept_incoming_migration(QIOChannel *ioc,
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞        }
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞        trace_migration_socket_incoming_accepted()
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞        qio_channel_set_name(QIO_CHANNEL(sioc), 
> "migration-socket-incoming")
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ +    qio_channel_set_feature(QIO_CHANNEL(sioc), 
> QIO_CHANNEL_FEATURE_SHUTDOWN)
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞        migration_channel_process_incoming(migrate_get_current(),
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞                                           QIO_CHANNEL(sioc))
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞        object_unref(OBJECT(sioc))
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ My test will not hang any more.
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ 原始邮件
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ 发件人： address@hidden
> ＞ ＞＞＞ 收件人：王广10165992 address@hidden
> ＞ ＞＞＞ 抄送人： address@hidden address@hidden
> ＞ ＞＞＞ 日 期 ：2017年03月21日 15:58
> ＞ ＞＞＞ 主 题 ：Re: [Qemu-devel]  答复: Re:  [BUG]COLO failover hang
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ Hi,Wang.
> ＞ ＞＞＞
> ＞ ＞＞＞ You can test this branch:
> ＞ ＞＞＞
> ＞ ＞＞＞ 
> https://github.com/coloft/qemu/tree/colo-v5.1-developing-COLO-frame-v21-with-shared-disk
> ＞ ＞＞＞
> ＞ ＞＞＞ and please follow wiki ensure your own configuration correctly.
> ＞ ＞＞＞
> ＞ ＞＞＞ http://wiki.qemu-project.org/Features/COLO
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ Thanks
> ＞ ＞＞＞
> ＞ ＞＞＞ Zhang Chen
> ＞ ＞＞＞
> ＞ ＞＞＞
> ＞ ＞＞＞ On 03/21/2017 03:27 PM, address@hidden wrote:
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ hi.
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ I test the git qemu master have the same problem.
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ (gdb) bt
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #0  qio_channel_socket_readv (ioc=0x7f65911b4e50, iov=0x7f64ef3fd880,
> ＞ ＞＞＞ ＞ niov=1, fds=0x0, nfds=0x0, errp=0x0) at io/channel-socket.c:461
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #1  0x00007f658e4aa0c2 in qio_channel_read
> ＞ ＞＞＞ ＞ (address@hidden, address@hidden "",
> ＞ ＞＞＞ ＞ address@hidden, address@hidden) at io/channel.c:114
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #2  0x00007f658e3ea990 in channel_get_buffer (opaque=＜optimized out＞,
> ＞ ＞＞＞ ＞ buf=0x7f65907cb838 "", pos=＜optimized out＞, size=32768) at
> ＞ ＞＞＞ ＞ migration/qemu-file-channel.c:78
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #3  0x00007f658e3e97fc in qemu_fill_buffer (f=0x7f65907cb800) at
> ＞ ＞＞＞ ＞ migration/qemu-file.c:295
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #4  0x00007f658e3ea2e1 in qemu_peek_byte (address@hidden,
> ＞ ＞＞＞ ＞ address@hidden) at migration/qemu-file.c:555
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #5  0x00007f658e3ea34b in qemu_get_byte (address@hidden) at
> ＞ ＞＞＞ ＞ migration/qemu-file.c:568
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #6  0x00007f658e3ea552 in qemu_get_be32 (address@hidden) at
> ＞ ＞＞＞ ＞ migration/qemu-file.c:648
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #7  0x00007f658e3e66e5 in colo_receive_message (f=0x7f65907cb800,
> ＞ ＞＞＞ ＞ address@hidden) at migration/colo.c:244
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #8  0x00007f658e3e681e in colo_receive_check_message (f=＜optimized
> ＞ ＞＞＞ ＞ out＞, address@hidden,
> ＞ ＞＞＞ ＞ address@hidden)
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞     at migration/colo.c:264
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #9  0x00007f658e3e740e in colo_process_incoming_thread
> ＞ ＞＞＞ ＞ (opaque=0x7f658eb30360 ＜mis_current.31286＞) at migration/colo.c:577
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #10 0x00007f658be09df3 in start_thread () from /lib64/libpthread.so.0
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #11 0x00007f65881983ed in clone () from /lib64/libc.so.6
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ (gdb) p ioc-＞name
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ $2 = 0x7f658ff7d5c0 "migration-socket-incoming"
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ (gdb) p ioc-＞features        Do not support QIO_CHANNEL_FEATURE_SHUTDOWN
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ $3 = 0
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ (gdb) bt
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #0  socket_accept_incoming_migration (ioc=0x7fdcceeafa90,
> ＞ ＞＞＞ ＞ condition=G_IO_IN, opaque=0x7fdcceeafa90) at migration/socket.c:137
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #1  0x00007fdcc6966350 in g_main_dispatch (context=＜optimized out＞) at
> ＞ ＞＞＞ ＞ gmain.c:3054
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #2  g_main_context_dispatch (context=＜optimized out＞,
> ＞ ＞＞＞ ＞ address@hidden) at gmain.c:3630
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #3  0x00007fdccb8a6dcc in glib_pollfds_poll () at util/main-loop.c:213
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #4  os_host_main_loop_wait (timeout=＜optimized out＞) at
> ＞ ＞＞＞ ＞ util/main-loop.c:258
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #5  main_loop_wait (address@hidden) at
> ＞ ＞＞＞ ＞ util/main-loop.c:506
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #6  0x00007fdccb526187 in main_loop () at vl.c:1898
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ #7  main (argc=＜optimized out＞, argv=＜optimized out＞, envp=＜optimized
> ＞ ＞＞＞ ＞ out＞) at vl.c:4709
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ (gdb) p ioc-＞features
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ $1 = 6
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ (gdb) p ioc-＞name
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ $2 = 0x7fdcce1b1ab0 "migration-socket-listener"
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ May be socket_accept_incoming_migration should
> ＞ ＞＞＞ ＞ call qio_channel_set_feature(ioc, QIO_CHANNEL_FEATURE_SHUTDOWN)??
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ thank you.
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ 原始邮件
> ＞ ＞＞＞ ＞ address@hidden
> ＞ ＞＞＞ ＞ address@hidden
> ＞ ＞＞＞ ＞ address@hidden@huawei.com＞
> ＞ ＞＞＞ ＞ *日 期 ：*2017年03月16日 14:46
> ＞ ＞＞＞ ＞ *主 题 ：**Re: [Qemu-devel] COLO failover hang*
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ On 03/15/2017 05:06 PM, wangguang wrote:
> ＞ ＞＞＞ ＞ ＞   am testing QEMU COLO feature described here [QEMU
> ＞ ＞＞＞ ＞ ＞ Wiki](http://wiki.qemu-project.org/Features/COLO).
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞ When the Primary Node panic,the Secondary Node qemu hang.
> ＞ ＞＞＞ ＞ ＞ hang at recvmsg in qio_channel_socket_readv.
> ＞ ＞＞＞ ＞ ＞ And  I run  { 'execute': 'nbd-server-stop' } and { "execute":
> ＞ ＞＞＞ ＞ ＞ "x-colo-lost-heartbeat" } in Secondary VM's
> ＞ ＞＞＞ ＞ ＞ monitor,the  Secondary Node qemu still hang at recvmsg .
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞ I found that the colo in qemu is not complete yet.
> ＞ ＞＞＞ ＞ ＞ Do the colo have any plan for development?
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ Yes, We are developing. You can see some of patch we pushing.
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ ＞ Has anyone ever run it successfully? Any help is appreciated!
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ In our internal version can run it successfully,
> ＞ ＞＞＞ ＞ The failover detail you can ask Zhanghailiang for help.
> ＞ ＞＞＞ ＞ Next time if you have some question about COLO,
> ＞ ＞＞＞ ＞ please cc me and zhanghailiang address@hidden
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ Thanks
> ＞ ＞＞＞ ＞ Zhang Chen
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞ centos7.2+qemu2.7.50
> ＞ ＞＞＞ ＞ ＞ (gdb) bt
> ＞ ＞＞＞ ＞ ＞ #0  0x00007f3e00cc86ad in recvmsg () from /lib64/libpthread.so.0
> ＞ ＞＞＞ ＞ ＞ #1  0x00007f3e0332b738 in qio_channel_socket_readv (ioc=＜optimized 
> out＞,
> ＞ ＞＞＞ ＞ ＞ iov=＜optimized out＞, niov=＜optimized out＞, fds=0x0, nfds=0x0, 
> errp=0x0) at
> ＞ ＞＞＞ ＞ ＞ io/channel-socket.c:497
> ＞ ＞＞＞ ＞ ＞ #2  0x00007f3e03329472 in qio_channel_read (address@hidden,
> ＞ ＞＞＞ ＞ ＞ address@hidden "", address@hidden,
> ＞ ＞＞＞ ＞ ＞ address@hidden) at io/channel.c:97
> ＞ ＞＞＞ ＞ ＞ #3  0x00007f3e032750e0 in channel_get_buffer (opaque=＜optimized out＞,
> ＞ ＞＞＞ ＞ ＞ buf=0x7f3e05910f38 "", pos=＜optimized out＞, size=32768) at
> ＞ ＞＞＞ ＞ ＞ migration/qemu-file-channel.c:78
> ＞ ＞＞＞ ＞ ＞ #4  0x00007f3e0327412c in qemu_fill_buffer (f=0x7f3e05910f00) at
> ＞ ＞＞＞ ＞ ＞ migration/qemu-file.c:257
> ＞ ＞＞＞ ＞ ＞ #5  0x00007f3e03274a41 in qemu_peek_byte (address@hidden,
> ＞ ＞＞＞ ＞ ＞ address@hidden) at migration/qemu-file.c:510
> ＞ ＞＞＞ ＞ ＞ #6  0x00007f3e03274aab in qemu_get_byte (address@hidden) at
> ＞ ＞＞＞ ＞ ＞ migration/qemu-file.c:523
> ＞ ＞＞＞ ＞ ＞ #7  0x00007f3e03274cb2 in qemu_get_be32 (address@hidden) at
> ＞ ＞＞＞ ＞ ＞ migration/qemu-file.c:603
> ＞ ＞＞＞ ＞ ＞ #8  0x00007f3e03271735 in colo_receive_message (f=0x7f3e05910f00,
> ＞ ＞＞＞ ＞ ＞ address@hidden) at migration/colo.c:215
> ＞ ＞＞＞ ＞ ＞ #9  0x00007f3e0327250d in colo_wait_handle_message 
> (errp=0x7f3d62bfaa48,
> ＞ ＞＞＞ ＞ ＞ checkpoint_request=＜synthetic pointer＞, f=＜optimized out＞) at
> ＞ ＞＞＞ ＞ ＞ migration/colo.c:546
> ＞ ＞＞＞ ＞ ＞ #10 colo_process_incoming_thread (opaque=0x7f3e067245e0) at
> ＞ ＞＞＞ ＞ ＞ migration/colo.c:649
> ＞ ＞＞＞ ＞ ＞ #11 0x00007f3e00cc1df3 in start_thread () from /lib64/libpthread.so.0
> ＞ ＞＞＞ ＞ ＞ #12 0x00007f3dfc9c03ed in clone () from /lib64/libc..so.6
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞ --
> ＞ ＞＞＞ ＞ ＞ View this message in context: 
> http://qemu.11.n7.nabble.com/COLO-failover-hang-tp473250.html
> ＞ ＞＞＞ ＞ ＞ Sent from the Developer mailing list archive at Nabble.com.
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞ --
> ＞ ＞＞＞ ＞ Thanks
> ＞ ＞＞＞ ＞ Zhang Chen
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞ ＞
> ＞ ＞＞＞
> ＞ ＞＞
> ＞ ＞ --
> ＞ ＞ Dr. David Alan Gilbert / address@hidden / Manchester, UK
> ＞ ＞
> ＞ ＞ .
> ＞ ＞
> ＞