[Qemu-devel] [Problem] qemu crash when vhost_net_start

[Xulei (Stone)]

Hi, all
Recently, I have a VM with a vhost-user network card created by qemu 2.6.0. 
Once, I restart OpenVSwitch service
and start this VM in the same time. I found qemu may probably crash with 
following stack:

(gdb) bt
#0  0x00007f0f9179a5d7 in raise () from /usr/lib64/libc.so.6
#1  0x00007f0f9179bcc8 in abort () from /usr/lib64/libc.so.6
#2  0x000000000045a202 in kvm_io_ioeventfd_add ()
#3  0x000000000045cffc in address_space_add_del_ioeventfds ()
#4  0x000000000045fa0e in address_space_update_ioeventfds ()
#5  0x0000000000460f40 in memory_region_transaction_commit ()
#6  0x0000000000461ce5 in memory_region_add_eventfd ()
#7  0x000000000066a1e5 in virtio_pci_set_host_notifier_internal ()
#8  0x00000000004ae08a in vhost_dev_enable_notifiers ()
#9  0x0000000000492743 in vhost_net_start_one ()
#10 0x00000000004930bf in vhost_net_start ()
#11 0x000000000048efd4 in virtio_net_vhost_status ()
#12 0x000000000048f16a in virtio_net_set_status ()
#13 0x0000000000686bcd in qmp_set_link ()
#14 0x000000000068dcc3 in net_vhost_user_event ()
#15 0x000000000051f043 in tcp_chr_new_client ()
#16 0x000000000051f10f in qemu_chr_socket_connected ()
#17 0x000000000073cb10 in qio_task_complete ()
#18 0x000000000073cb7b in gio_task_thread_result ()
#19 0x00007f0f929fb99a in g_main_context_dispatch () from 
/usr/lib64/libglib-2.0.so.0
#20 0x00000000006d2275 in os_host_main_loop_wait ()
#21 0x00000000006d2393 in main_loop_wait ()
#22 0x000000000052a0f2 in main_loop ()
#23 0x000000000041bcd3 in main ()

This seems a bug triggering when backend starts vhost_net and meanwhile the 
frontend rmmod/modprobe virtio-net.
Is this a known issue or any patch can fix this?

Thanks all~