机器运行过程中突然不能上网。测试ping外网失败。执行wifi操作得到如下崩溃信息：
[ 4390.640000] br-lan: port 2(ra0) entered disabled state
[ 4390.700000] WLAN:STA 00:a6:bc:6a:90:01(dev:ra0 rate:58Mbps singnal:-17dBm) disconnect
[ 4391.240000] CPU 0 Unable to handle kernel paging request at virtual address 00000000, epc == 8003b584, ra == 800221e4
[ 4391.250000] Oops[#2]:
[ 4391.250000] CPU: 0 PID: 6108 Comm: ifconfig Tainted: G D 3.18.29 #2
[ 4391.250000] task: 84f4ce88 ti: 84fa6000 task.ti: 84fa6000
[ 4391.250000] $ 0 : 00000000 00000000 00000000 00000001
[ 4391.250000] $ 4 : 00000000 ffffffe8 00000000 00000000
[ 4391.250000] $ 8 : 00000002 0000e400 00000000 00000000
[ 4391.250000] $12 : 000003fe 77601030 00000001 00000000
[ 4391.250000] $16 : 84e4c4d8 84e4c4d8 00000000 c0b55004
[ 4391.250000] $20 : 00000001 00000004 ffffffff 7feae804
[ 4391.250000] $24 : 00000000 80040c70
[ 4391.250000] $28 : 84fa6000 84fa7c48 00000000 800221e4
[ 4391.250000] Hi : 00000000
[ 4391.250000] Lo : 00000000
[ 4391.250000] epc : 8003b584 exit_creds+0x18/0x88
[ 4391.250000] Tainted: G D
[ 4391.250000] ra : 800221e4 __put_task_struct+0x60/0xa4
[ 4391.250000] Status: 1100e403 KERNEL EXL IE
[ 4391.250000] Cause : 00800008
[ 4391.250000] BadVA : 00000000
[ 4391.250000] PrId : 00019655 (MIPS 24KEc)
[ 4391.250000] Modules linked in: iptable_nat nf_nat_ipv4 nf_conntrack_ipv6 nf_conntrack_ipv4 ipt_REJECT ipt_MASQUERADE cp210x xt_time xt_tcpudp xt_state xt_nat xt_multiport xt_mark xt_mac xt_limit xt_id xt_conntrack xt_comment xt_TCPMSS xt_REDIRECT xt_LOG xt_CT usbserial nf_reject_ipv4 nf_nat_masquerade_ipv4 nf_nat_ftp nf_nat nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 nf_conntrack_rtcache nf_conntrack_ftp nf_conntrack iptable_raw iptable_mangle iptable_filter ip_tables i2c_ralink mt_wifi i2c_dev i2c_core ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 nf_log_common ip6table_raw ip6table_mangle ip6table_filter ip6_tables x_tables vfat fat autofs4 nls_utf8 nls_iso8859_1 nls_cp437 ipv6 usb_storage leds_gpio ohci_platform ohci_hcd ehci_platform ehci_hcd sd_mod scsi_mod gpio_button_hotplug ext4 jbd2 mbcache exfat drv_regopt usbcore nls_base usb_common crc16 crypto_hash
[ 4391.250000] Process ifconfig (pid: 6108, threadinfo=84fa6000, task=84f4ce88, tls=77fb0440)
[ 4391.250000] Stack : 84ca507c 00000004 ffffffff 7feae804 84e4c4d8 800221e4 00000004 84c7cadc
1100e403 00000000 84e4c4e0 8003a20c 00000000 00000001 00000001 00000008
c0b55000 00000004 871b7000 84c6fc58 00000010 c0b55000 00000010 00003548
84ca5060 84c07314 00000004 87122a00 00000004 84c7303c c0b55000 00000004
c0b55000 00000004 871b7000 84c2f184 83024800 80042e2c 83034af8 c0b55000
...
[ 4391.250000] Call Trace:
[ 4391.250000] [<8003b584>] exit_creds+0x18/0x88
[ 4391.250000] [<800221e4>] __put_task_struct+0x60/0xa4
[ 4391.250000] [<8003a20c>] kthread_stop+0x98/0xb4
[ 4391.250000] [<84c6fc58>] RtmpOSTaskKill+0x1c/0x34 [mt_wifi]
[ 4391.250000] [<84c07314>] MlmeHalt+0x20/0x1a8 [mt_wifi]
[ 4391.250000] [<84c2f184>] RTMPDrvClose+0xbc/0x274 [mt_wifi]
[ 4391.250000] [<84c70b1c>] rt28xx_close+0x24/0x38 [mt_wifi]
[ 4391.250000] [<84c244b0>] RTMP_COM_IoctlHandle+0x564/0x8d8 [mt_wifi]
[ 4391.250000] [<84c82d20>] ApCli_VirtualIF_Close+0x70/0x94 [mt_wifi]
[ 4391.250000] [<801e1c04>] __dev_close_many+0xb4/0xe4
[ 4391.250000] [<801e1d54>] __dev_close+0x28/0x44
[ 4391.250000] [<801e7dd0>] __dev_change_flags+0xb8/0x170
[ 4391.250000] [<801e7eb0>] dev_change_flags+0x28/0x70
[ 4391.250000] [<80245670>] devinet_ioctl+0x63c/0x674
[ 4391.250000] [<801cfc74>] sock_ioctl+0x2b0/0x30c
[ 4391.250000] [<800b007c>] do_vfs_ioctl+0x4d4/0x5e0
[ 4391.250000] [<800b01d8>] SyS_ioctl+0x50/0x94
[ 4391.250000] [<80006b5c>] handle_sys+0x11c/0x140
[ 4391.250000]
[ 4391.250000]
Code: 8c820244 00808021 8c840240 <8c420000> ae000240 c0830000 2462ffff e0820000 1040fffc
[ 4391.570000] ---[ end trace 35415dc3babe0560 ]---
请问这个可能是什么原因导致的呢？