From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59231) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZttCT-0002AM-0k for qemu-devel@nongnu.org; Wed, 04 Nov 2015 03:13:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZttCO-0007Le-3i for qemu-devel@nongnu.org; Wed, 04 Nov 2015 03:13:44 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:9075) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZttCN-0007Kx-Ai for qemu-devel@nongnu.org; Wed, 04 Nov 2015 03:13:40 -0500 References: <5638B041.50500@huawei.com> <56396C66.4000303@huawei.com> <5639794D.9030109@redhat.com> From: zhanghailiang Message-ID: <5639BE02.1000200@huawei.com> Date: Wed, 4 Nov 2015 16:12:50 +0800 MIME-Version: 1.0 In-Reply-To: <5639794D.9030109@redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [vhost-user BUG ?] QEMU process segfault when shutdown or reboot with vhost-user List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang , =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= Cc: "Michael S. Tsirkin" , peter.huangpeng@huawei.com, "stefanha@redhat.com" , "qemu-devel@nongnu.org" On 2015/11/4 11:19, Jason Wang wrote: > > > On 11/04/2015 10:24 AM, zhanghailiang wrote: >> On 2015/11/3 22:54, Marc-André Lureau wrote: >>> Hi >>> >>> On Tue, Nov 3, 2015 at 2:01 PM, zhanghailiang >>> wrote: >>>> The corresponding codes where gdb reports error are: (We have added >>>> some >>>> codes in net.c) >>> >>> Can you reproduce with unmodified qemu? Could you give instructions >>> to do so? >>> >> >> OK, i will try to do it. There is nothing special, we run iperf tool >> in VM, >> and then shutdown or reboot it. There is change you can catch segfault. >> >>>> ssize_t qemu_deliver_packet(NetClientState *sender, >>>> unsigned flags, >>>> const uint8_t *data, >>>> size_t size, >>>> void *opaque) >>>> { >>>> NetClientState *nc = opaque; >>>> ssize_t ret; >>>> >>>> if (nc->link_down) { >>>> return size; >>>> } >>>> >>>> if (nc->receive_disabled) { >>>> return 0; >>>> } >>>> >>>> if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) { >>>> ret = nc->info->receive_raw(nc, data, size); >>>> } else { >>>> ret = nc->info->receive(nc, data, size); ----> Here is >>>> 510 line >>>> } >>>> >>>> I'm not quite familiar with vhost-user, but for vhost-user, these two >>>> callback functions seem to be always NULL, >>>> Why we can come here ? >>> >>> You should not come here, vhost-user has nc->receive_disabled (it >>> changes in 2.5) >>> >> >> I have looked at the newest codes, i think we can still have chance to >> come here, since we will change nc->receive_disable to false >> temporarily in >> qemu_flush_or_purge_queued_packets(), there is no difference between >> 2.3 and 2.5 >> for this. >> Besides, is it possible for !QTAILQ_EMPTY(&queue->packets) to be true >> in qemu_net_queue_flush() for vhost-user ? > > The only thing I can image is self announcing. Are you trying to do > migration? 2.5 only support sending rarp through this. > Hmm, it's not triggered by migration, For qemu-2.5, IMHO, it doesn't have such problem, since the callback function 'receive' is not NULL. It is vhost_user_receive(). > And it's better to have a breakpoint to see why a packet was queued for > vhost-user. The stack trace may also help in this case. > OK, i'm trying to reproduce it. Thanks, zhanghailiang >> >> i will try to reproduce it by using newest qemu. >> >> Thanks, >> zhanghailiang >> > > > . >