MTX caused Kernel Driver crash

Kernel failure message 1:
[153294.300898] ------------[ cut here ]------------
[153294.300957] WARNING: at /tmp/buildd/linux-2.6-2.6.32/debian/build/source_i386_none/drivers/usb/serial/usb-serial.c:440 serial_unthrottle+0x44/0x5a [usbserial]()
[153294.300976] Hardware name: AOA150
[153294.300984] Modules linked in: nls_utf8 nls_cp437 vfat fat usb_storage acpi_cpufreq cpufreq_stats cpufreq_conservative cpufreq_userspace cpufreq_powersave parport_pc ppdev lp parport sco bridge stp bnep rfcomm l2cap crc16 bluetooth binfmt_misc uinput fuse loop snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_midi arc4 snd_rawmidi ecb snd_seq_midi_event ath5k mac80211 snd_seq i915 uvcvideo drm_kms_helper ath drm videodev snd_timer snd_seq_device i2c_algo_bit v4l1_compat acerhdf ftdi_sio snd i2c_i801 joydev usbhid video soundcore cfg80211 usbserial i2c_core pcspkr hid output rng_core battery psmouse serio_raw button rfkill wmi evdev snd_page_alloc led_class ac processor ext3 jbd mbcache sd_mod crc_t10dif ata_generic ata_piix uhci_hcd libata ehci_hcd thermal r8169 scsi_mod usbcore mii nls_base thermal_sys [last unloaded: scsi_wait_scan]
[153294.301343] Pid: 20444, comm: megatunix Tainted: G        W  2.6.32-5-686 #1
[153294.301356] Call Trace:
[153294.301382]  [<c1030725>] ? warn_slowpath_common+0x5e/0x8a
[153294.301404]  [<c103075b>] ? warn_slowpath_null+0xa/0xc
[153294.301447]  [<f81844ac>] ? serial_unthrottle+0x44/0x5a [usbserial]
[153294.301469]  [<c1193061>] ? tty_unthrottle+0x2d/0x36
[153294.301488]  [<c1191f12>] ? n_tty_flush_buffer+0xa/0x5c
[153294.301508]  [<c11946b6>] ? tty_ldisc_flush+0x1c/0x2e
[153294.301527]  [<c1194dd1>] ? tty_port_close_end+0xf/0x99
[153294.301563]  [<f81847b3>] ? serial_close+0x60/0x72 [usbserial]
[153294.301583]  [<c1190084>] ? tty_release_dev+0x14c/0x3ee
[153294.301603]  [<c108df0c>] ? release_pages+0x11c/0x124
[153294.301646]  [<c118f66d>] ? tty_ioctl+0x0/0x8b1
[153294.301666]  [<c10bdad0>] ? vfs_ioctl+0x1c/0x5f
[153294.301686]  [<c1190335>] ? tty_release+0xf/0x18
[153294.301705]  [<c10b4207>] ? __fput+0xd5/0x170
[153294.301724]  [<c10b1900>] ? filp_close+0x4e/0x54
[153294.301742]  [<c10b1960>] ? sys_close+0x5a/0x8d
[153294.301762]  [<c10030fb>] ? sysenter_do_call+0x12/0x28
[153294.301777] ---[ end trace d755ea40ad66d0bc ]---