Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761998AbYGBVWq (ORCPT ); Wed, 2 Jul 2008 17:22:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754407AbYGBVU7 (ORCPT ); Wed, 2 Jul 2008 17:20:59 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:44517 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760895AbYGBVUz (ORCPT ); Wed, 2 Jul 2008 17:20:55 -0400 Date: Wed, 2 Jul 2008 14:18:30 -0700 From: Greg KH To: Helge Hafting Cc: linux-kernel , linux-usb@vger.kernel.org Subject: Re: 2.6.26-rc2 WARNING from usb-serial, and then my gps is dead Message-ID: <20080702211830.GA26541@kroah.com> References: <485E984B.1030306@aitel.hist.no> <20080622184253.GB18502@kroah.com> <48622C5E.5020204@aitel.hist.no> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48622C5E.5020204@aitel.hist.no> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3683 Lines: 84 On Wed, Jun 25, 2008 at 01:30:38PM +0200, Helge Hafting wrote: > Greg KH wrote: >> On Sun, Jun 22, 2008 at 08:22:03PM +0200, Helge Hafting wrote: >>> This is what I got: >>> ------------[ cut here ]------------ >>> WARNING: at drivers/usb/serial/usb-serial.c:306 serial_write+0x62/0x89 >>> [usbserial]() >>> Modules linked in: pl2303 usbserial sbs sbshc coretemp piix pcmcia >>> ata_piix iTCO_wdt ata_generic bay hci_usb intel_agp >>> Pid: 10, comm: events/1 Tainted: G W 2.6.26-rc2-hh1 #1 >>> >>> Call Trace: >>> [] warn_on_slowpath+0x51/0x7a >>> [] __wake_up+0x38/0x4f >>> [] __queue_work+0x23/0x33 >>> [] queue_work+0x37/0x40 >>> [] :pl2303:pl2303_write+0xf2/0x101 >>> [] :usbserial:serial_write+0x62/0x89 >>> [] tty_put_char+0x2b/0x2d >>> [] echo_char+0x47/0x60 >>> [] n_tty_receive_buf+0x2b4/0xd76 >>> [] __switch_to+0xa2/0x396 >>> [] hrtick_set+0x88/0xf6 >>> [] thread_return+0x70/0xb4 >>> [] lock_timer_base+0x26/0x4c >>> [] flush_to_ldisc+0xf8/0x185 >>> [] flush_to_ldisc+0x0/0x185 >>> [] run_workqueue+0x80/0x112 >>> [] worker_thread+0xd9/0xe8 >>> [] autoremove_wake_function+0x0/0x2e >>> [] worker_thread+0x0/0xe8 >>> [] kthread+0x47/0x73 >>> [] schedule_tail+0x28/0x5d >>> [] child_rip+0xa/0x12 >>> [] kthread+0x0/0x73 >>> [] child_rip+0x0/0x12 >>> >>> ---[ end trace 656e180042992f9e ]--- >>> I looked at the dmesg log because I have had lots of trouble with my gps >>> lately. I first suspected the cable, but then I saw this. >>> >>> After this, I have to restart gpsd, and perhaps replug the cable to get >>> things going again. Until it happens again. This is a 64-bit dualcore >>> laptop. >> Ick, that's not nice. >> Can you enable debugging for the usb-serial core: >> echo 1 > /sys/module/usbserial/parameters/debug >> and then run whatever program you were running that causes this warning >> and then send us the kernel log? > > USB logging sure creates lots of data. > 8.4M of log bzipped into 237kB here: > http://www.aitel.hist.no/~helgehaf/usbtrouble1.log.bz2 > > This contains: > * Kernel log all the way from bootup (2.6.26-rc8) > * An USB incident before I turned USB logging on > * An USB incident after I turned USB logging on > > Almost all of it is these two lines repeating forewer: > drivers/usb/serial/usb-serial.c: serial_chars_in_buffer = port 0 > drivers/usb/serial/usb-serial.c: serial_write_room - port 0 > > The port numbers change a couple of times throughout the log. Ah, sorry for the delay, got sidetracked with other bugs... In looking at this further, it's just a warning that is triggering, nothing to really be woried about right now. Alan Cox has done a lot of work in this area in the tty layer rework for 2.6.27 that should keep this race from happening in the future (something is calling write_room on a port that was previously closed, not very nice.) So you can safely ignore it, it should not be causing any problems, only showing examples of a flaky connection/hardware. thanks for your patience, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/