I have just had 3 of these kernel warnings with backtraces while using my USB serial adapter. I'm using the current kernel released with Lucid, on 32-bit x86. My serial adapter is an Arkmicro Technologies Inc. ARK3116 Serial.
It's not just innocuous warnings. A script talking to the device at the other and of the serial cable is getting garbage back from the serial port. I've seen the garbage repeatedly during an hour long session (in fact, can't use the script - the data coming back is too unreliable). Specifically, it contains repeated portions of text sent earlier, over and over. strace confirms the kernel serial driver is returning these repeated bits of text, not a bug in the script. It's using Perl and libexpect-perl. Strangely, when I use minicom to talk to the device manually I don't get these repeated selections of old text back. I had suspected the device at the other end, until I started getting apport crash reports towards the end of my hour long session. Now I suspect a bug in the usb-serial driver or the tty layer - both were changed near this kernel version. I will keep a copy of my script, to see if this can be reproduced another time. Rather than a one-off, this looks quite likely to duplicated as at least some of these other reports: #533982 WARNING: at /build/buildd/linux-2.6.32/drivers/usb/serial/usb-serial.c:440 serial_unthrottle 0x7b/0x80 [usbserial]() #433604 WARNING: at /build/buildd/linux-2.6.31/drivers/usb/serial/usb-serial.c:448 serial_unthrottle+0x76/0x80 [usbserial]() #471157 WARNING: at /build/buildd/linux-2.6.31/drivers/usb/serial/usb-serial.c:446 serial_unthrottle+0x76/0x80 [usbserial]() #470007 WARNING: at /build/buildd/linux-2.6.31/drivers/usb/serial/usb-serial.c:446 serial_unthrottle+0x76/0x80 [usbserial]() #407939 System freeze after WARNING: at /build/buildd/linux-2.6.31/drivers/usb/serial/usb-serial.c:374 serial_write+0xb9/0xc0 [usbserial]() #286703 WARNING: at /build/buildd/linux-2.6.27/drivers/usb/serial/usb-serial.c:311 serial_write+0xa4/0xb0 [usbserial]() #438311 WARNING: at /build/buildd/linux-2.6.31/drivers/usb/serial/usb-serial.c:401 serial_write+0xbb/0xc0 [usbserial]() Notice a common theme? They are all USB serial. These are my variations on the warnings: Mar 19 10:16:17 localhost kernel: [33130.516205] usb 3-2: new full speed USB device using uhci_hcd and address 2 Mar 19 10:16:17 localhost kernel: [33130.672508] usb 3-2: configuration #1 chosen from 1 choice Mar 19 10:16:18 localhost kernel: [33130.698253] usbcore: registered new interface driver usbserial Mar 19 10:16:18 localhost kernel: [33130.698283] USB Serial support registered for generic Mar 19 10:16:18 localhost kernel: [33130.698343] usbcore: registered new interface driver usbserial_generic Mar 19 10:16:18 localhost kernel: [33130.698348] usbserial: USB Serial Driver core Mar 19 10:16:18 localhost kernel: [33130.700253] USB Serial support registered for ark3116 Mar 19 10:16:18 localhost kernel: [33130.700275] ark3116 3-2:1.0: ark3116 converter detected Mar 19 10:16:18 localhost kernel: [33130.727487] usb 3-2: ark3116 converter now attached to ttyUSB0 Mar 19 10:16:18 localhost kernel: [33130.727527] usbcore: registered new interface driver ark3116 Mar 19 12:34:53 localhost kernel: [41446.080220] ------------[ cut here ]------------ Mar 19 12:34:53 localhost kernel: [41446.080240] WARNING: at /build/buildd/linux-2.6.32/drivers/usb/serial/usb-serial.c:406 serial_write_room+0x75/0x80 [usbserial]() Mar 19 12:34:53 localhost kernel: [41446.080247] Hardware name: Amilo Si 1520 Mar 19 12:34:53 localhost kernel: [41446.080251] Modules linked in: ark3116 usbserial binfmt_misc ppdev kqemu kvm_intel kvm sha256_generic aes_i586 aes_generic dm_crypt joydev snd_hda_codec_conexant snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy arc4 snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device sbp2 iwl3945 snd iwlcore soundcore mac80211 ricoh_mmc sdhci_pci sdhci led_class psmouse serio_raw snd_page_alloc cfg80211 lp parport fbcon tileblit font bitblit softcursor vga16fb vgastate ohci1394 i915 drm_kms_helper drm i2c_algo_bit e100 mii ieee1394 video intel_agp output agpgart Mar 19 12:34:53 localhost kernel: [41446.080367] Pid: 9, comm: events/0 Not tainted 2.6.32-16-generic #25-Ubuntu Mar 19 12:34:53 localhost kernel: [41446.080372] Call Trace: Mar 19 12:34:53 localhost kernel: [41446.080386] [<c014a9d2>] warn_slowpath_common+0x72/0xa0 Mar 19 12:34:53 localhost kernel: [41446.080396] [<fe486735>] ? serial_write_room+0x75/0x80 [usbserial] Mar 19 12:34:53 localhost kernel: [41446.080406] [<fe486735>] ? serial_write_room+0x75/0x80 [usbserial] Mar 19 12:34:53 localhost kernel: [41446.080413] [<c014aa1a>] warn_slowpath_null+0x1a/0x20 Mar 19 12:34:53 localhost kernel: [41446.080422] [<fe486735>] serial_write_room+0x75/0x80 [usbserial] Mar 19 12:34:53 localhost kernel: [41446.080432] [<c03ad8d3>] ? tty_put_char+0x33/0x40 Mar 19 12:34:53 localhost kernel: [41446.080440] [<c03b3ecd>] tty_write_room+0x1d/0x20 Mar 19 12:34:53 localhost kernel: [41446.080447] [<c03b191d>] process_echoes+0x4d/0x2d0 Mar 19 12:34:53 localhost kernel: [41446.080453] [<c03b148d>] ? echo_char+0x4d/0xa0 Mar 19 12:34:53 localhost kernel: [41446.080461] [<c03b35a1>] n_tty_receive_char+0x3a1/0x780 Mar 19 12:34:53 localhost kernel: [41446.080468] [<c03b3b4e>] n_tty_receive_buf+0x1ce/0x410 Mar 19 12:34:53 localhost kernel: [41446.080478] [<c012a2f8>] ? default_spin_lock_flags+0x8/0x10 Mar 19 12:34:53 localhost kernel: [41446.080488] [<c059dcbf>] ? _spin_lock_irqsave+0x2f/0x50 Mar 19 12:34:53 localhost kernel: [41446.080496] [<c012a2f8>] ? default_spin_lock_flags+0x8/0x10 Mar 19 12:34:53 localhost kernel: [41446.080504] [<c03b62a1>] flush_to_ldisc+0x151/0x180 Mar 19 12:34:53 localhost kernel: [41446.080513] [<c0161c6e>] run_workqueue+0x8e/0x150 Mar 19 12:34:53 localhost kernel: [41446.080520] [<c03b6150>] ? flush_to_ldisc+0x0/0x180 Mar 19 12:34:53 localhost kernel: [41446.080528] [<c0161db4>] worker_thread+0x84/0xe0 Mar 19 12:34:53 localhost kernel: [41446.080536] [<c0165d30>] ? autoremove_wake_function+0x0/0x50 Mar 19 12:34:53 localhost kernel: [41446.080544] [<c0161d30>] ? worker_thread+0x0/0xe0 Mar 19 12:34:53 localhost kernel: [41446.080550] [<c0165aa4>] kthread+0x74/0x80 Mar 19 12:34:53 localhost kernel: [41446.080557] [<c0165a30>] ? kthread+0x0/0x80 Mar 19 12:34:53 localhost kernel: [41446.080565] [<c0104087>] kernel_thread_helper+0x7/0x10 Mar 19 12:34:53 localhost kernel: [41446.080570] ---[ end trace 5d571f4d930148a4 ]--- Mar 19 12:36:14 localhost kernel: [41526.840310] ------------[ cut here ]------------ Mar 19 12:36:14 localhost kernel: [41526.840329] WARNING: at /build/buildd/linux-2.6.32/drivers/usb/serial/usb-serial.c:440 serial_unthrottle+0x7b/0x80 [usbserial]() Mar 19 12:36:14 localhost kernel: [41526.840335] Hardware name: Amilo Si 1520 Mar 19 12:36:14 localhost kernel: [41526.840339] Modules linked in: ark3116 usbserial binfmt_misc ppdev kqemu kvm_intel kvm sha256_generic aes_i586 aes_generic dm_crypt joydev snd_hda_codec_conexant snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy arc4 snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device sbp2 iwl3945 snd iwlcore soundcore mac80211 ricoh_mmc sdhci_pci sdhci led_class psmouse serio_raw snd_page_alloc cfg80211 lp parport fbcon tileblit font bitblit softcursor vga16fb vgastate ohci1394 i915 drm_kms_helper drm i2c_algo_bit e100 mii ieee1394 video intel_agp output agpgart Mar 19 12:36:14 localhost kernel: [41526.840454] Pid: 8076, comm: catch_bootloade Tainted: G W 2.6.32-16-generic #25-Ubuntu Mar 19 12:36:14 localhost kernel: [41526.840460] Call Trace: Mar 19 12:36:14 localhost kernel: [41526.840473] [<c014a9d2>] warn_slowpath_common+0x72/0xa0 Mar 19 12:36:14 localhost kernel: [41526.840484] [<fe48658b>] ? serial_unthrottle+0x7b/0x80 [usbserial] Mar 19 12:36:14 localhost kernel: [41526.840493] [<fe48658b>] ? serial_unthrottle+0x7b/0x80 [usbserial] Mar 19 12:36:14 localhost kernel: [41526.840501] [<c014aa1a>] warn_slowpath_null+0x1a/0x20 Mar 19 12:36:14 localhost kernel: [41526.840509] [<fe48658b>] serial_unthrottle+0x7b/0x80 [usbserial] Mar 19 12:36:14 localhost kernel: [41526.840519] [<c059cb49>] ? mutex_lock+0x19/0x40 Mar 19 12:36:14 localhost kernel: [41526.840527] [<c03b448b>] tty_unthrottle+0x3b/0x50 Mar 19 12:36:14 localhost kernel: [41526.840534] [<c03b253e>] reset_buffer_flags+0xbe/0xf0 Mar 19 12:36:14 localhost kernel: [41526.840541] [<c03b258b>] n_tty_flush_buffer+0x1b/0x80 Mar 19 12:36:14 localhost kernel: [41526.840548] [<c03b598c>] tty_ldisc_flush+0x2c/0x50 Mar 19 12:36:14 localhost kernel: [41526.840555] [<c03b68a0>] tty_port_close_end+0x20/0xe0 Mar 19 12:36:14 localhost kernel: [41526.840564] [<fe486b6a>] serial_close+0x6a/0xb0 [usbserial] Mar 19 12:36:14 localhost kernel: [41526.840573] [<c03adc43>] ? tty_fasync+0x43/0x140 Mar 19 12:36:14 localhost kernel: [41526.840581] [<c03afef0>] tty_release_dev+0x120/0x500 Mar 19 12:36:14 localhost kernel: [41526.840590] [<c015d0cf>] ? ptrace_stop+0xbf/0x160 Mar 19 12:36:14 localhost kernel: [41526.840597] [<c015d209>] ? ptrace_notify+0x99/0xc0 Mar 19 12:36:14 localhost kernel: [41526.840606] [<c03b02e7>] tty_release+0x17/0x30 Mar 19 12:36:14 localhost kernel: [41526.840614] [<c0206c3f>] __fput+0xdf/0x1f0 Mar 19 12:36:14 localhost kernel: [41526.840622] [<c0206d6d>] fput+0x1d/0x30 Mar 19 12:36:14 localhost kernel: [41526.840629] [<c02032ac>] filp_close+0x4c/0x80 Mar 19 12:36:14 localhost kernel: [41526.840636] [<c0203358>] sys_close+0x78/0xc0 Mar 19 12:36:14 localhost kernel: [41526.840643] [<c01033ec>] syscall_call+0x7/0xb Mar 19 12:36:14 localhost kernel: [41526.840649] ---[ end trace 5d571f4d930148a5 ]--- -- WARNING: at /build/buildd/linux-2.6.32/drivers/usb/serial/usb-serial.c:440 serial_unthrottle 0x7b/0x80 [usbserial]() https://bugs.launchpad.net/bugs/533982 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs