system went unresponsive and had to hard reboot

without not much load on the machine, it suddenly went busy and went unresponsive. it could not respond to keyboard or mouse movement or neither would move to another other tty's. there is some log which may hint about the problem. can someone please help identify the problem? EDIT: also sometimes my internet just stalls; i cannot see any packets going through when using tcpdump. i have to reconnect again to the wifi network for the packets to start flowing again; but i have noticed these problems after i have recently changed my provider to Sky, Uk and they have provided a router with model number, SR101 sky router settings region: europe; channel: auto; mode: auto; auth: wpa2-psk (aes) /var/log/syslog kernel: [ 7593.778323] ------------[ cut here ]------------ kernel: [ 7593.778352] WARNING: at /build/buildd/linux-3.5.0/drivers/net/wireless/brcm80211/brcmsmac/main.c:7953 brcms_c_wait_for_tx_comp kernel: [ 7593.778355] Hardware name: Satellite R630 kernel: [ 7593.778357] Modules linked in: pci_stub vboxpci(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) bnep rfcomm parport_pc ppdev joydev kvm arc4 snd_hda_codec_hdmi snd_hda_codec_realtek brcmsmac mac80211 brcmutil cfg80211 cordic uvcvideo videobuf2_core videodev videobu snd_hwdep snd_pcm microcode snd_seq_midi snd_rawmidi toshiba_acpi sparse_keymap snd_seq_midi_event wmi toshiba_b mac_hid snd intel_ips lpc_ich soundcore snd_page_alloc i915 drm_kms_helper psmouse serio_raw mei bcma drm i2c_algo_bit video l [last unloaded: e1000e] kernel: [ 7593.778416] Pid: 18560, comm: kworker/u:1 Tainted: G O 3.5.0-17-generic #28-Ubuntu kernel: [ 7593.778418] Call Trace: kernel: [ 7593.778428] [] warn_slowpath_common+0x7f/0xc0 kernel: [ 7593.778432] [] warn_slowpath_null+0x1a/0x20 kernel: [ 7593.778445] [] brcms_c_wait_for_tx_completion+0x99/0xb0 [brcmsmac] kernel: [ 7593.778453] [] brcms_ops_flush+0x3b/0x60 [brcmsmac] kernel: [ 7593.778473] [] ieee80211_scan_work+0x34d/0x5e0 [mac80211] kernel: [ 7593.778481] [] ? finish_task_switch+0x4a/0xf0 kernel: [ 7593.778485] [] process_one_work+0x12a/0x420 kernel: [ 7593.778498] [] ? ieee80211_run_deferred_scan+0x80/0x80 [mac80211] kernel: [ 7593.778502] [] worker_thread+0x12e/0x2f0 kernel: [ 7593.778506] [] ? manage_workers.isra.26+0x200/0x200 kernel: [ 7593.778510] [] kthread+0x93/0xa0 kernel: [ 7593.778516] [] kernel_thread_helper+0x4/0x10 kernel: [ 7593.778520] [] ? kthread_freezable_should_stop+0x70/0x70 kernel: [ 7593.778523] [] ? gs_change+0x13/0x13 kernel: [ 7593.778526] ---[ end trace 6499cba8e2fb8557 ]--- kernel modules pci_stub vboxpci vboxnetadp vboxnetflt vboxdrv parport_pc ppdev bnep rfcomm joydev btusb bluetooth snd_hda_codec_hdmi snd_hda_codec_realtek coretemp kvm_intel kvm arc4 brcmsmac mac80211 brcmutil cfg80211 cordic snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_seq_midi uvcvideo videobuf2_core videodev videobuf2_vmalloc snd_rawmidi videobuf2_memops snd_seq_midi_event snd_seq snd_timer snd_seq_device toshiba_acpi sparse_keymap wmi toshiba_bluetooth snd mac_hid microcode i915 psmouse serio_raw lpc_ich bcma drm_kms_helper intel_ips drm soundcore snd_page_alloc lp i2c_algo_bit mei video parport sdhci_pci sdhci uname Linux 3.5.0-17-generic #28-Ubuntu SMP Tue Oct 9 19:31:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux network information from lshw *-network description: Wireless interface physical id: 4 logical name: wlan0 serial: b4:74:9f:5b:a0:57 capabilities: ethernet physical wireless configuration: broadcast=yes driver=brcmsmac driverversion=3.5.0-17-generic firmware=N/A ip=192.168.0.4 link=yes multicast=yes wireless=IEEE 802.11bgn EDIT: wireless info ~$ sudo lspci -vv -s 02:00.0 02:00.0 Network controller: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller (rev 01) .. Capabilities: [16c v1] Power Budgeting Kernel driver in use: bcma-pci-bridge Kernel modules: bcma log when wifi cannot send anymore packets and wifi needs to be turned off and on kernel: [ 1791.266956] Pid: 7728, comm: kworker/u:0 Tainted: G O 3.5.0-17-generic #28-Ubuntu kernel: [ 1791.266958] Call Trace: kernel: [ 1791.266968] [] warn_slowpath_common+0x7f/0xc0 kernel: [ 1791.266971] [] warn_slowpath_null+0x1a/0x20 kernel: [ 1791.266980] [] brcms_c_wait_for_tx_completion+0x99/0xb0 [brcmsmac] kernel: [ 1791.266986] [] brcms_ops_flush+0x3b/0x60 [brcmsmac] kernel: [ 1791.267006] [] ieee80211_scan_work+0x34d/0x5e0 [mac80211] kernel: [ 1791.267013] [] ? finish_task_switch+0x4a/0xf0 kernel: [ 1791.267016] [] process_one_work+0x12a/0x420 kernel: [ 1791.267027] [] ? ieee80211_run_deferred_scan+0x80/0x80 [mac80211] kernel: [ 1791.267030] [] worker_thread+0x12e/0x2f0 kernel: [ 1791.267033] [] ? manage_workers.isra.26+0x200/0x200 kernel: [ 1791.267037] [] kthread+0x93/0xa0 kernel: [ 1791.267042] [] kernel_thread_helper+0x4/0x10 kernel: [ 1791.267046] [] ? kthread_freezable_should_stop+0x70/0x70 kernel: [ 1791.267049] [] ? gs_change+0x13/0x13 kernel: [ 1791.267050] ---[ end trace 56f847a7c78d0da0 ]--- kernel: [ 2004.872993] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2006.035759] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2006.036162] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2006.546185] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2007.543524] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2008.542929] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2408.822335] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2408.868303] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2408.937553] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2408.953977] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2408.958060] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2408.976166] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2409.264878] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2409.766008] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2409.793456] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2409.807420] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2409.834179] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2409.994049] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2410.062283] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2410.067860] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2410.785801] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2410.837042] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2410.915746] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2411.060400] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2411.063439] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 NetworkManager: (wlan0): device state change: activated -> unavailable (reason 'none') [100 20 0] NetworkManager: (wlan0): deactivating device (reason 'none') kernel: [ 2411.249095] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2411.276068] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 kernel: [ 2411.276755] ieee80211 phy0: >brcms_c_prec_enq_head: No where to go, prec == 4 NetworkManager: (wlan0): canceled DHCP transaction, DHCP client pid 1768