Re: [Qemu-devel] [PATCH] vhost-user: fix watcher need be removed when vhost-user hotplug

[wangyunjian]

On Tue, May 9, 2017 at 5:04 PM Yunjian Wang <address@hidden> wrote:

> > From: w00273186 <address@hidden>
> >
> > "nc" is freed after hotplug vhost-user, but the watcher don't be removed.
> >
> 
> 
> > The QEMU crash when the watcher access the "nc" on socket disconnect.
> >
> >
> Do you have a reproducer? thanks
>

reproduce steps:

1. virsh attach-device vm0 vhost-user.xml
2. virsh detach-device vm0 vhost-user.xml
3. virsh attach-device vm0 vhost-user.xml
4. service openvswitch restart
5. repeat step 2~4

The vhost-user xml:

    <interface type='vhostuser'>
      <mac address='00:01:01:00:10:41'/>
      <source type='unix' path='/var/run/vhost-user/tap1' mode='client'/>
      <model type='virtio'/>
      <driver queues='8'/>
　</interface>

Thanks

> 
> > Call Trace:
> >     #0  object_get_class (address@hidden) at qom/object.c:751
> >     #1  0x00007fc031c79f41 in qemu_chr_fe_disconnect (be=<optimized out>)
> > at chardev/char.c:1048
> >     #2  0x00007fc031bd62e0 in net_vhost_user_watch (chan=<optimized out>,
> > cond=<optimized out>, opaque=<optimized out>) at net/vhost-user.c:191
> >     #3  0x00007fc02c23e99a in g_main_context_dispatch () from
> > /lib64/libglib-2.0.so.0
> >     #4  0x00007fc031ccfc0c in glib_pollfds_poll () at util/main-loop.c:213
> >     #5  os_host_main_loop_wait (timeout=<optimized out>) at
> > util/main-loop.c:261
> >     #6  main_loop_wait (address@hidden) at
> > util/main-loop.c:517
> >     #7  0x00007fc03193bc87 in main_loop () at vl.c:1899
> >     #8  main (argc=<optimized out>, argv=<optimized out>, envp=<optimized
> > out>) at vl.c:4719
> >
> > Signed-off-by: Yunjian Wang <address@hidden>
> > ---
> >  net/vhost-user.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/net/vhost-user.c b/net/vhost-user.c
> > index 00a0c1c..5cc2178 100644
> > --- a/net/vhost-user.c
> > +++ b/net/vhost-user.c
> > @@ -155,6 +155,10 @@ static void vhost_user_cleanup(NetClientState *nc)
> >
> >          qemu_chr_fe_deinit(&s->chr);
> >          object_unparent(OBJECT(chr));
> > +        if (s->watch) {
> > +            g_source_remove(s->watch);
> > +            s->watch = 0;
> > +        }
> >      }
> >
> >      qemu_purge_queued_packets(nc);
> > --
> > 1.8.3.1
> >
> >
> >
> > --
> Marc-André Lureau