Re: [Qemu-devel] vhost-user: fix crash when chardev-remove

[黄淮]

Hi 
I tested  on qemu-2.7.1 release version.


test case:
1. host run ovs-dpdk.  start  vhost-user mode vm
2. chardev-add 
socket,id=char-client-002-2,path=/usr/local/var/run/openvswitch/client-002-2,server=on

netdev_add vhost-user,id=client-002-2, 
,chardev=char-client-002-2,vhostforce=on

device_add 
virtio-net-pci,netdev=client-002-2,mac=00:22:79:29:d2:6c,id=netdev-client-002-2 
   ... wait 10 s
device_del  netdev-client-002-2
netdev_del  client-002-2
chardev-remove char-client-002-2
   
ovs-vsctl del-port  client-002-2
(gdb) bt
#0  0x7f80483265f7 in raise () from /lib64/libc.so.6
#1  0x7f8048327ce8 in abort () from /lib64/libc.so.6
#2  0x7f804831f566 in __assert_fail_base () from /lib64/libc.so.6
#3  0x7f804831f612 in __assert_fail () from /lib64/libc.so.6
#4  0x7f804b729bec in get_vhost_net (nc=) at 
/opt/cloud/contrib/qemu-2.7.1/hw/net/vhost_net.c:415
#5  0x7f804b726f31 in virtio_net_vhost_status (status=0 '\000', 
n=0x7f804db841c0) at /opt/cloud/contrib/qemu-2.7.1/hw/net/virtio-net.c:121
#6  virtio_net_set_status (vdev=, status=) at 
/opt/cloud/contrib/qemu-2.7.1/hw/net/virtio-net.c:224
#7  0x7f804b73ead6 in virtio_set_status (vdev=vdev@entry=0x7f804db841c0, 
val=val@entry=0 '\000') at /opt/cloud/contrib/qemu-2.7.1/hw/virtio/virtio.c:760
#8  0x7f804b8f869c in virtio_ioport_write (val=0, addr=18, 
opaque=0x7f804db7be80) at hw/virtio/virtio-pci.c:400
#9  virtio_pci_config_write (opaque=0x7f804db7be80, addr=18, val=0, 
size=) at hw/virtio/virtio-pci.c:525
#10 0x7f804b6fa0db in memory_region_write_accessor (mr=0x7f804db7c710, 
addr=18, value=, size=1, shift=, mask=, attrs=...)
at /opt/cloud/contrib/qemu-2.7.1/memory.c:525
#11 0x7f804b6f8079 in access_with_adjusted_size (addr=addr@entry=18, 
value=value@entry=0x7f7ffeffc958, size=size@entry=1, access_size_min=,
access_size_max=, access=access@entry=0x7f804b6fa060 
, mr=mr@entry=0x7f804db7c710, 
attrs=attrs@entry=...)
at /opt/cloud/contrib/qemu-2.7.1/memory.c:591
#12 0x7f804b6fc6f5 in memory_region_dispatch_write 
(mr=mr@entry=0x7f804db7c710, addr=addr@entry=18, data=0, size=size@entry=1, 
attrs=attrs@entry=...)
at /opt/cloud/contrib/qemu-2.7.1/memory.c:1327
#13 0x7f804b6b93bb in address_space_write_continue (mr=0x7f804db7c710, l=1, 
addr1=18, len=1, buf=0x7f804b4bc000 , 
attrs=..., addr=4114,
as=0x7f804bfaa3e0 ) at 
/opt/cloud/contrib/qemu-2.7.1/exec.c:2556
#14 address_space_write (as=, addr=, attrs=..., 
buf=, len=) at 
/opt/cloud/contrib/qemu-2.7.1/exec.c:2601
#15 0x7f804b6b9a3d in address_space_rw (as=, 
addr=addr@entry=4114, attrs=..., attrs@entry=..., buf=, 
len=len@entry=1, is_write=is_write@entry=true)
at /opt/cloud/contrib/qemu-2.7.1/exec.c:2703
#16 0x7f804b6f6fd5 in kvm_handle_io (count=1, size=1, direction=, data=, attrs=..., port=4114) at 
/opt/cloud/contrib/qemu-2.7.1/kvm-all.c:1791
#17 kvm_cpu_exec (cpu=cpu@entry=0x7f804d8d1de0) at 
/opt/cloud/contrib/qemu-2.7.1/kvm-all.c:1955
#18 0x7f804b6e4e76 in qemu_kvm_cpu_thread_fn (arg=0x7f804d8d1de0) at 
/opt/cloud/contrib/qemu-2.7.1/cpus.c:1078
#19 0x7f80486b9dc5 in start_thread () from /lib64/libpthread.so.0
#20 0x7f80483e728d in clone () from /lib64/libc.so.6


After fix this:
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index f2d49ad..4037cf4 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -412,7 +412,6 @@ VHostNetState *get_vhost_net(NetClientState *nc)
 break;
 case NET_CLIENT_DRIVER_VHOST_USER:
 vhost_net = vhost_user_get_vhost_net(nc);
-assert(vhost_net);


(gdb) bt
#0  qemu_chr_disconnect (chr=0x0) at qemu-char.c:4081
#1  0x7fdb4f538cf0 in net_vhost_user_watch (chan=, 
cond=, opaque=) at net/vhost-user.c:195
#2  0x7fdb4cd617aa in g_main_context_dispatch () from 
/lib64/libglib-2.0.so.0
#3  0x7fdb4f5798f0 in glib_pollfds_poll () at main-loop.c:213
#4  os_host_main_loop_wait (timeout=) at main-loop.c:258
#5  main_loop_wait (nonblocking=) at main-loop.c:506
#6  0x7fdb4f2dbfa7 in main_loop () at vl.c:1909
#7  main (argc=, argv=, envp=) at 
vl.c:4618




I think it`s because vhost-user client mode ,  2.7+ version new 
function(reconnect).   After qemu char-remove, the watch fd process didn`t 
stop. When ovs-dpdk remove port  and close watch fd,  qemu crashed.


Thanks
Huanghuai  



At 2017-01-11 23:02:26, "Marc-André Lureau" <marcandre.lur...@gmail.com> wrote:

Hi



On Wed, Jan 11, 2017 at 3:32 PM 黄淮 <h158...@126.com> wrote:

From: Huai Huang<h158...@126.com>





Could you describe a bit more the crash and provide a backtrace?

 
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index f2d49ad..4037cf4 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -412,7 +412,6 @@ VHostNetState *get_vhost_net(NetClientState *nc)
 break;
 case NET_CLIENT_DRIVER_VHOST_USER:
 vhost_net = vhost_user_get_vhost_net(nc);
-assert(vhost_net);



This w

[Qemu-devel] vhost-user: fix crash when chardev-remove

[黄淮]

From: Huai Huang


diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index f2d49ad..4037cf4 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -412,7 +412,6 @@ VHostNetState *get_vhost_net(NetClientState *nc)
 break;
 case NET_CLIENT_DRIVER_VHOST_USER:
 vhost_net = vhost_user_get_vhost_net(nc);
-assert(vhost_net);
 break;
 default:
 break;
diff --git a/net/vhost-user.c b/net/vhost-user.c
index b0595f8..4e54478 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -160,7 +160,10 @@ static void vhost_user_cleanup(NetClientState *nc)
 qemu_chr_fe_release(s->chr);
 s->chr = NULL;
 }
-
+if (s->watch) {
+g_source_remove(s->watch);
+s->watch = 0;
+}
 qemu_purge_queued_packets(nc);
 }


@@ -192,7 +195,8 @@ static gboolean net_vhost_user_watch(GIOChannel *chan, 
GIOCondition cond,
 {
 VhostUserState *s = opaque;


-qemu_chr_disconnect(s->chr);
+if (s->chr)
+qemu_chr_disconnect(s->chr);


 return FALSE;
 }