# cat /proc/766/stack 
[<c02abbe4>] usb_start_wait_urb+0x64/0x12c
[<c02abe98>] usb_control_msg+0xc4/0xf8
[<c0292fc8>] rt2x00usb_vendor_request+0xa4/0x128
[<c02931c8>] rt2x00usb_vendor_req_buff_lock+0xb8/0xe4
[<c0293360>] rt2x00usb_vendor_request_buff+0x70/0xcc
[<c029ef7c>] rt2x00usb_register_multiwrite+0x40/0x48
[<c0298070>] rt2800_config_wcid+0x68/0x70
[<c029893c>] rt2800_init_registers+0x8a4/0x1310
[<c029abe0>] rt2800_enable_radio+0x28/0x2118
[<c02a003c>] rt2800usb_set_device_state+0x130/0x18c
[<c028d6f8>] rt2x00lib_enable_radio+0x44/0xc0
[<c028e0d8>] rt2x00lib_start+0x58/0xd8
[<c028ed00>] rt2x00mac_start+0x28/0x2c
[<c041ec7c>] ieee80211_do_open+0x278/0x898
[<c041f318>] ieee80211_open+0x7c/0x80
[<c032bf38>] __dev_open+0xb8/0x118
[<c032c184>] __dev_change_flags+0x80/0x144
[<c032c2c4>] dev_change_flags+0x18/0x50
[<c0339184>] do_setlink+0x350/0x880
[<c033a5c8>] rtnl_newlink+0x430/0x4a0
[<c033a100>] rtnetlink_rcv_msg+0x160/0x1f8
[<c03450f0>] netlink_rcv_skb+0xb4/0xc8
[<c0338c6c>] rtnetlink_rcv+0x20/0x2c
[<c0344b48>] netlink_unicast+0x184/0x1e8
[<c0344ec8>] netlink_sendmsg+0x270/0x2e8
[<c0315fb8>] sock_sendmsg+0x80/0xa0
[<c0316e38>] ___sys_sendmsg.part.24+0x28c/0x29c
[<c0318040>] __sys_sendmsg+0x50/0x80
[<c0318080>] SyS_sendmsg+0x10/0x14
[<c00093a0>] ret_fast_syscall+0x0/0x2c
[<ffffffff>] 0xffffffff