[Bug 310734] [NEW] rfcomm does not release its devices sometimes

[Sergei (Nolar) Vasilyev]

Public bug reported:

I use rfcomm to connect to bluetooth GPS receiver.
/etc/bluetooth/rfcomm.conf is configured to bind four devices
(rfcomm0..3) to the same bt-addr and channel. There are these four
devices in /dev/. Sometimes it works perfectly: cat /dev/rfcomm0
connects to gps-device and prints data. Also 'gpsbabel' is used to
download mtk-log via this serial port.

But sometimes something inside the system locks this device. And since then it is impossible to connect to rfcomm0. It says:
  cat: /dev/rfcomm0: Connection timed out
OR, less often, silently exits with no error message (and no data being transfered). Using rfcomm1, rfcomm2, rfcomm3 solves the problem for a while, until they will be locked too. These devices never unlock on their own. Only rebooting helps.

During device being locked, `lsof` says nothing on them. After releasing
all rfcomms (`sudo rfcomm release all`) and ensuring all of them really
were released (`rfcomm -a`), `lsmod` says module rfcomm is still used
2-4 times with no dependencies. Number of dependencies seems to always
be even (2,4,6), never odd. Removing module rfcomm or bluetooth or any
other from bluez stack is impossible (they are being "used").

I suggest, this is some kind of kernel-side locking; maybe because the device is not released properly or something like that.
There is no any strict way to reproduce this behavior. Only intensive using (opening-closing) sometimes makes rfcomm devices 
"used to death".


Ubuntu Intrepid 8.10 (updated from 8.04) with all up-to-date updates.

$ lsb_release -rd
Description:	Ubuntu 8.10
Release:	8.10

$ uname -a
Linux Nolar-XPS 2.6.27-9-generic #1 SMP Thu Nov 20 21:57:00 UTC 2008 i686 GNU/Linux

$ dpkg-query -l | grep bluez
ii  bluez                                      4.12-0ubuntu5                           Bluetooth tools and daemons
ii  bluez-alsa                                 4.12-0ubuntu5                           Bluetooth audio support
rc  bluez-audio                                3.36-1ubuntu2                           Bluetooth audio support
ii  bluez-btsco                                1:0.50-0ubuntu3                         Bluez Bluetooth SCO tool
ii  bluez-cups                                 4.12-0ubuntu5                           Bluetooth printer driver for CUPS
ii  bluez-gnome                                1.8-0ubuntu1                            Bluetooth utilities for GNOME
ii  bluez-gstreamer                            4.12-0ubuntu5                           Bluetooth gstreamer support
ii  bluez-hcidump                              1.42-1build1                            Analyses Bluetooth HCI packets
rc  bluez-network                              3.36-1ubuntu2                           Bluetooth network support
ii  bluez-utils                                4.12-0ubuntu5                           Transitional package
ii  python-bluez                               0.15-1build1                            Python wrappers around BlueZ for rapid bluet


Write what to check if you need more info.

** Affects: bluez (Ubuntu)
     Importance: Undecided
         Status: New

-- 
rfcomm does not release its devices sometimes
https://bugs.launchpad.net/bugs/310734
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