hi, all I do a hotplug detach a network in a thread, because virDomainDetachDeviceFlags maybe asynchronous, so I do like follow: cb_para->cluster_id = info->cluster_id; cb_para->group_id = info->group_id; cb_para->vsys_id = info->vsysid; cb_para->vnf_id = info->vnf_id; cb_para->conn = conn; cb_para->time_out = 20*1000;//20s cb_para->call_id = virConnectDomainEventRegisterAny(conn, dom, VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED, VIR_DOMAIN_EVENT_CALLBACK(vnf_control_del_network_cb), cb_para, vnf_control_del_network_cb_free); flags |= VIR_DOMAIN_AFFECT_CONFIG; if (virDomainIsActive(dom) == 1) { flags |= VIR_DOMAIN_AFFECT_LIVE; } cb_para->timer_id = virEventAddTimeout(cb_para->time_out, vnf_control_del_network_timeout_cb, cb_para, vnf_control_del_network_cb_free); ret = virDomainDetachDeviceFlags(dom, xml, flags); //above run in a thread function void vnf_control_del_network_cb(virConnectPtr conn, virDomainPtr dom, const char *dev,void * opaque) { struct vnf_del_netwk_opaque * arg = (struct vnf_del_netwk_opaque *)opaque; if(0 == virConnectDomainEventDeregisterAny(conn, arg->call_id)) { VNF_DBG("succ to deRegister, conn:%p, call id:%d\n", conn, arg->call_id); } else { VNF_DBG("fail to deRegister, conn:%p, call id:%d\n", conn, arg->call_id); } .................... virEventRemoveTimeout(arg->timer_id); } void vnf_control_del_network_timeout_cb(int timer, void *opaque) { struct vnf_del_netwk_opaque * arg = (struct vnf_del_netwk_opaque *)opaque; ................ if(0 == virConnectDomainEventDeregisterAny(arg->conn, arg->call_id)) { //here, dead lock ,are thoses APIs not correct using ?? VNF_DBG("succ to deRegister, conn:%p, call id:%d\n", arg->conn, arg->call_id); } else { VNF_DBG("fail to deRegister, conn:%p, call id:%d\n", arg->conn, arg->call_id); } virEventRemoveTimeout(arg->timer_id); } (gdb) i threads Id Target Id Frame 7 Thread 0x7f29fa5ff700 (LWP 104950) "vnfd" 0x00007f2a064f656d in nanosleep () from /lib64/libc.so.6 6 Thread 0x7f29f9bfe700 (LWP 104951) "vnfd" 0x00007f2a0761851d in __lll_lock_wait () from /lib64/libpthread.so.0 5 Thread 0x7f29f8dff700 (LWP 104952) "vnfd" 0x00007f2a064f656d in nanosleep () from /lib64/libc.so.6 4 Thread 0x7f29f7fff700 (LWP 104953) "vnfd" 0x00007f2a064f656d in nanosleep () from /lib64/libc.so.6 3 Thread 0x7f29f71ff700 (LWP 104954) "vnfd" 0x00007f2a064f656d in nanosleep () from /lib64/libc.so.6 2 Thread 0x7f29f63ff700 (LWP 104955) "vnfd" 0x00007f2a064f656d in nanosleep () from /lib64/libc.so.6 * 1 Thread 0x7f2a087f8900 (LWP 104946) "vnfd" 0x00007f2a06530183 in epoll_wait () from /lib64/libc.so.6 (gdb) thread 6 [Switching to thread 6 (Thread 0x7f29f9bfe700 (LWP 104951))] #0 0x00007f2a0761851d in __lll_lock_wait () from /lib64/libpthread.so.0 (gdb) bt #0 0x00007f2a0761851d in __lll_lock_wait () from /lib64/libpthread.so.0 #1 0x00007f2a07613e1b in _L_lock_812 () from /lib64/libpthread.so.0 #2 0x00007f2a07613ce8 in pthread_mutex_lock () from /lib64/libpthread.so.0 #3 0x00007f2a072a1a0e in remoteConnectClose () from /lib64/libvirt.so.0 #4 0x00007f2a072b2740 in virConnectDispose () from /lib64/libvirt.so.0 #5 0x00007f2a0710bbab in virObjectUnref () from /lib64/libvirt.so.0 #6 0x00007f2a07195577 in virObjectEventCallbackFree () from /lib64/libvirt.so.0 #7 0x00007f2a07196532 in virObjectEventStateDeregisterID () from /lib64/libvirt.so.0 #8 0x00007f2a07287238 in remoteConnectDomainEventDeregisterAny () from /lib64/libvirt.so.0 #9 0x00007f2a072d36d7 in virConnectDomainEventDeregisterAny () from /lib64/libvirt.so.0 #10 0x0000000000405bce in vnf_control_del_network_timeout_cb (timer=<optimized out>, opaque=0x7f29e9e99de0) at vnf_mgt/vnf_control.c:1293 #11 0x00007f2a070d20e9 in virEventPollRunOnce () from /lib64/libvirt.so.0 #12 0x00007f2a070d0a42 in virEventRunDefaultImpl () from /lib64/libvirt.so.0 #13 0x000000000040d099 in vnf_worker_proc (arg=<optimized out>) at vnf_mgt/vnf_control.c:1727 #14 0x00007f2a07611e25 in start_thread () from /lib64/libpthread.so.0 #15 0x00007f2a0652fbad in clone () from /lib64/libc.so.6 (gdb) f 10 #10 0x0000000000405bce in vnf_control_del_network_timeout_cb (timer=<optimized out>, opaque=0x7f29e9e99de0) at vnf_mgt/vnf_control.c:1293 1293 if(0 == virConnectDomainEventDeregisterAny(arg->conn, arg->call_id)) { (gdb) p arg->time_id There is no member named time_id. (gdb) set print pretty (gdb) p *arg $1 = { cluster_id = 0, vsys_id = 0, group_id = 2, vnf_id = 1, call_id = 0, timer_id = 16, time_out = 20000, conn = 0x7f29f8013000 } (gdb) quit A debugging session is active.