'ifconfig tun0 destroy' gets stuck

[Andriy Gapon]

I experience a problem where vpnc can not exit cleanly and gets stuck.
pstree shows this chain:
 |-+= 31375 root vpnc
 | \-+- 13412 root /bin/sh /usr/local/sbin/vpnc-script-custom
 |   \--- 13446 root ifconfig tun0 destroy

$ procstat -k 13446
  PID    TID COMM             TDNAME           KSTACK
13446 102739 ifconfig         -                mi_switch sleepq_switch
sleepq_wait _cv_wait_unlock tun_destroy tun_clone_destroy ifc_simple_destroy
if_clone_destroyif if_clone_destroy ifioctl soo_ioctl kern_ioctl sys_ioctl
amd64_syscall Xfast_syscall

My system is FreeBSD 10.0-CURRENT amd64 r236503.

I think that this started happening recently but I am not sure exactly when.
Maybe after recent vpnc-scripts update or maybe after base system + kernel update.

Any help/hint is very welcome.
Thank you!

-- 
Andriy Gapon