Comment 22 for bug 556317

I'm seeing very similar (identical?) behavior. For me, the problem seems to occur almost immediately when the device (an ftdi FT232RL) is opened. Reinserting the device often seems to resolve the problem.

This particular device spews a very large amount of data at 230.4kbps, beginning the moment the device is opened. (Perhaps this is helpful info?)

May 27 19:58:30 ebolson-laptop kernel: [26123.514212] ------------[ cut here ]------------
May 27 19:58:30 ebolson-laptop kernel: [26123.514227] WARNING: at /home/achiang/kernels/ubuntu-lucid/drivers/usb/serial/usb-serial.c:440 serial_unthrottle+0x8e/0x90 [usbserial]()
May 27 19:58:30 ebolson-laptop kernel: [26123.514232] Hardware name: 2516CTO
May 27 19:58:30 ebolson-laptop kernel: [26123.514235] Modules linked in: ftdi_sio usbserial binfmt_misc ppdev vboxnetadp vboxnetflt vboxdrv rfcomm arc4 iwlagn thinkpad_acpi sco iwlcore bridge stp mac80211 snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq bnep snd_timer snd_seq_device l2cap btusb bluetooth joydev uvcvideo videodev v4l1_compat v4l2_compat_ioctl32 fbcon tileblit font bitblit softcursor snd sdhci_pci nvram video nvidia(P) sdhci psmouse soundcore snd_page_alloc output cfg80211 serio_raw led_class vga16fb vgastate intel_agp lp parport usbhid hid ohci1394 ahci e1000e ieee1394
May 27 19:58:30 ebolson-laptop kernel: [26123.514310] Pid: 16014, comm: java Tainted: P 2.6.32-22-generic #33
May 27 19:58:30 ebolson-laptop kernel: [26123.514313] Call Trace:
May 27 19:58:30 ebolson-laptop kernel: [26123.514327] [<ffffffff81066d0b>] warn_slowpath_common+0x7b/0xc0
May 27 19:58:30 ebolson-laptop kernel: [26123.514332] [<ffffffff81066d64>] warn_slowpath_null+0x14/0x20
May 27 19:58:30 ebolson-laptop kernel: [26123.514339] [<ffffffffa0b6d61e>] serial_unthrottle+0x8e/0x90 [usbserial]
May 27 19:58:30 ebolson-laptop kernel: [26123.514346] [<ffffffff8132fa99>] tty_unthrottle+0x49/0x60
May 27 19:58:30 ebolson-laptop kernel: [26123.514351] [<ffffffff8132d801>] reset_buffer_flags+0xd1/0x100
May 27 19:58:30 ebolson-laptop kernel: [26123.514356] [<ffffffff8132d84d>] n_tty_flush_buffer+0x1d/0x90
May 27 19:58:30 ebolson-laptop kernel: [26123.514361] [<ffffffff81330bdf>] ? tty_ldisc_try+0x4f/0x60
May 27 19:58:30 ebolson-laptop kernel: [26123.514366] [<ffffffff81331307>] tty_ldisc_flush+0x37/0x60
May 27 19:58:30 ebolson-laptop kernel: [26123.514371] [<ffffffff813324be>] tty_port_close_end+0x2e/0x100
May 27 19:58:30 ebolson-laptop kernel: [26123.514377] [<ffffffffa0b6dc79>] serial_close+0x89/0xc0 [usbserial]
May 27 19:58:30 ebolson-laptop kernel: [26123.514384] [<ffffffff8132ac13>] tty_release_dev+0x163/0x5e0
May 27 19:58:30 ebolson-laptop kernel: [26123.514390] [<ffffffff81159f1f>] ? destroy_inode+0x2f/0x60
May 27 19:58:30 ebolson-laptop kernel: [26123.514397] [<ffffffff8132b0ae>] tty_release+0x1e/0x30
May 27 19:58:30 ebolson-laptop kernel: [26123.514403] [<ffffffff81144305>] __fput+0xf5/0x210
May 27 19:58:30 ebolson-laptop kernel: [26123.514408] [<ffffffff81144445>] fput+0x25/0x30
May 27 19:58:30 ebolson-laptop kernel: [26123.514412] [<ffffffff8114053d>] filp_close+0x5d/0x90
May 27 19:58:30 ebolson-laptop kernel: [26123.514418] [<ffffffff81068d8f>] put_files_struct+0x7f/0xf0
May 27 19:58:30 ebolson-laptop kernel: [26123.514424] [<ffffffff81068e54>] exit_files+0x54/0x70
May 27 19:58:30 ebolson-laptop kernel: [26123.514429] [<ffffffff8106b3ab>] do_exit+0x14b/0x380
May 27 19:58:30 ebolson-laptop kernel: [26123.514436] [<ffffffff81540cce>] ? _spin_lock+0xe/0x20
May 27 19:58:30 ebolson-laptop kernel: [26123.514442] [<ffffffff8106b635>] do_group_exit+0x55/0xd0
May 27 19:58:30 ebolson-laptop kernel: [26123.514449] [<ffffffff8107bf77>] get_signal_to_deliver+0x1d7/0x3d0
May 27 19:58:30 ebolson-laptop kernel: [26123.514458] [<ffffffff81012a35>] do_signal+0x75/0x1c0
May 27 19:58:30 ebolson-laptop kernel: [26123.514463] [<ffffffff81096562>] ? futex_wake+0x112/0x130
May 27 19:58:30 ebolson-laptop kernel: [26123.514468] [<ffffffff81098ce9>] ? do_futex+0xc9/0x1b0
May 27 19:58:30 ebolson-laptop kernel: [26123.514474] [<ffffffff81012bdd>] do_notify_resume+0x5d/0x80
May 27 19:58:30 ebolson-laptop kernel: [26123.514479] [<ffffffff8101347e>] int_signal+0x12/0x17
May 27 19:58:30 ebolson-laptop kernel: [26123.514484] ---[ end trace 64101a36f4c835ca ]---
May 27 19:58:55 ebolson-laptop kernel: [26148.088296] ------------[ cut here ]------------

Linux ebolson-laptop 2.6.32-22-generic #33 SMP Thu Apr 22 14:56:10 MDT 2010 x86_64 GNU/Linux