Only the option driver implements the send_setup callback; it uses the
SET_CONTROL_LINE_STATE request in CDC ACM to generate DTR/RTS signals
on the port. This is not driver-specific though and is needed by other
drivers, so move the function to the usb_wwan driver (with formatting
tweaks), and replace the callback pointer with a flag that enables the
request.
Suggested-by: NBjørn Mork <bjorn@mork.no>
Suggested-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NDavid Ward <david.ward@ll.mit.edu>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Silence read-urb resubmission errors when the device is going away.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use tty-port initialised flag rather than private flag to determine when
port is closing down.

Since the tty-port flag is set prior to dropping DTR/RTS (when HUPCL is
set) this avoid submitting the read urbs when resuming the interface in
dtr_rts() only to immediately kill them again in shutdown().
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Promote failed-submission messages in open() and write() to error log
level.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove some more outdated or superfluous comments.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove superfluous and cryptic comment from close.

It should be obvious that we're balancing the autopm_put in open (and
that operation already mentions the autopm_get done in the USB serial
core).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Clean up and rename delay-urb submission function using a more
descriptive name.

Also add comment on locking assumptions.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use usb_get_serial_data() rather than accessing the private pointer
directly.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make resume error messages uniform.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As the port interrupt URB is submitted by the subdriver at open, we
should also kill it explicitly at suspend (even though this will be
taken care of by USB serial core otherwise).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove redundant usb_kill_urb from port remove, which is called
post-shutdown (close).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The driver does not implement set_termios so the operation can be left
unset (tty will do the tty_termios_copy_hw for us).

Note that the send_setup call is bogus as it really only sets DTR/RTS
to their current values.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The tty-port implementation has already made sure that DTR/RTS have been
raised by calling dtr_rts so remove the redundant call from open.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure that needs_remote_wake up is always set when there are open
ports.

Currently close() would unconditionally set needs_remote_wakeup to 0
even though there might still be open ports. This could lead to blocked
input and possibly dropped data on devices that do not support remote
wakeup (and which must therefore not be runtime suspended while open).

Add an open_ports counter (protected by the susp_lock) and only clear
needs_remote_wakeup when the last port is closed.

Note that there are currently no multi-port drivers using the usb_wwan
implementation.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There's no reason not to try sending off any further delayed write urbs,
should one urb-submission fail.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Keep trying to submit urbs rather than bail out on first read-urb
submission error, which would also prevent I/O for any further ports
from being resumed.

Instead keep an error count, for all types of failed submissions, and
let USB core know that something went wrong.

Also make sure to always clear the suspended flag. Currently a failed
read-urb submission would prevent cached writes as well as any
subsequent writes from being submitted until next suspend-resume cycle,
something which may not even necessarily happen.

Note that USB core currently only logs an error if an interface resume
failed.

Fixes: 383cedc3 ("USB: serial: full autosuspend support for the
option driver")

Cc: <stable@vger.kernel.org>	# v2.6.32
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The interrupt urb was submitted unconditionally at resume, something
which could lead to a NULL-pointer dereference in the urb completion
handler as resume may be called after the port and port data is gone.

Fix this by making sure the interrupt urb is only submitted and active
when the port is open.

Fixes: 383cedc3 ("USB: serial: full autosuspend support for the
option driver")

Cc: <stable@vger.kernel.org>  # v2.6.32: 032129cbSigned-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The delayed-write queue was never emptied at shutdown (close), something
which could lead to leaked urbs if the port is closed before being
runtime resumed due to a write.

When this happens the output buffer would not drain on close
(closing_wait timeout), and after consecutive opens, writes could be
corrupted with previously buffered data, transfered with reduced
throughput or completely blocked.

Note that unbusy_queued_urb() was simply moved out of CONFIG_PM.

Fixes: 383cedc3 ("USB: serial: full autosuspend support for the
option driver")

Cc: <stable@vger.kernel.org>	# v2.6.32
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix race between write() and suspend() which could lead to writes being
dropped (or I/O while suspended) if the device is runtime suspended
while a write request is being processed.

Specifically, suspend() releases the susp_lock after determining the
device is idle but before setting the suspended flag, thus leaving a
window where a concurrent write() can submit an urb.

Fixes: 383cedc3 ("USB: serial: full autosuspend support for the
option driver")

Cc: <stable@vger.kernel.org>	# v2.6.32
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We find a race between write and resume. usb_wwan_resume run play_delayed()
and spin_unlock, but intfdata->suspended still is not set to zero.
At this time usb_wwan_write is called and anchor the urb to delay
list. Then resume keep running but the delayed urb have no chance
to be commit until next resume. If the time of next resume is far
away, tty will be blocked in tty_wait_until_sent during time. The
race also can lead to writes being reordered.

This patch put play_Delayed and intfdata->suspended together in the
spinlock, it's to avoid the write race during resume.

Fixes: 383cedc3 ("USB: serial: full autosuspend support for the
option driver")
Signed-off-by: Nxiao jin <jin.xiao@intel.com>
Signed-off-by: NZhang, Qi1 <qi1.zhang@intel.com>
Reviewed-by: NDavid Cohen <david.a.cohen@linux.intel.com>
Cc: <stable@vger.kernel.org>	# v2.6.32
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When enable usb serial for modem data, sometimes the tty is blocked
in tty_wait_until_sent because portdata->out_busy always is set and
have no chance to be cleared.

We find a bug in write error path. usb_wwan_write set portdata->out_busy
firstly, then try autopm async with error. No out urb submit and no
usb_wwan_outdat_callback to this write, portdata->out_busy can't be
cleared.

This patch clear portdata->out_busy if usb_wwan_write try autopm async
with error.

Fixes: 383cedc3 ("USB: serial: full autosuspend support for the
option driver")
Signed-off-by: Nxiao jin <jin.xiao@intel.com>
Signed-off-by: NZhang, Qi1 <qi1.zhang@intel.com>
Reviewed-by: NDavid Cohen <david.a.cohen@linux.intel.com>
Cc: <stable@vger.kernel.org>	# v2.6.32
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Mostly scripted conversion of the smp_mb__* barriers.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Fix regression introduced by commit 8e493ca1 ("USB: usb_wwan: fix
bulk-urb allocation") by making sure to require both bulk-in and out
endpoints during port probe.

The original option driver (which usb_wwan is based on) was written
under the assumption that either endpoint could be missing, but
evidently this cannot have been tested properly. Specifically, it would
handle opening a device without bulk-in (but would blow up during resume
which was implemented later), but not a missing bulk-out in write()
(although it is handled in some places such as write_room()).

Fortunately (?), the driver also got the test for missing endpoints
wrong so the urbs were in fact always allocated, although they would be
initialised using the wrong endpoint address (0) and any submission of
such an urb would fail.

The commit mentioned above fixed the test for missing endpoints but
thereby exposed the other bugs which would now generate null-pointer
exceptions rather than failed urb submissions.

The regression was introduced in v3.7, but the offending commit was also
marked for stable.
Reported-by: NRafał Miłecki <zajec5@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Tested-by: NRafał Miłecki <zajec5@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove redundant error messages on allocation failures, which have
already been logged.

Cc: Joe Perches <joe@perches.com>
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This fixes an issue where the bulk-in urb used for incoming data transfer
is not resubmitted if the packet recieved contains an error status.  This
results in the driver locking until the port is closed and re-opened.

Tested on a custom board with a Cinterion GSM module.
Signed-off-by: NMatt Burtch <matt@grid-net.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This moves the allocation of minor device numbers from a static array to
be dynamic, using the idr interface.  This means that you could
potentially get "gaps" in a minor number range for a single USB serial
device with multiple ports, but all should still work properly.

We remove the 'minor' field from the usb_serial structure, as it no
longer makes any sense for it (use the field in the usb_serial_port
structure if you really want to know this number), and take the fact
that we were overloading a number in this field to determine if we had
initialized the minor numbers or not, and just use a flag variable
instead.

Note, we still have the limitation of 255 USB to serial devices in the
system, as that is all we are registering with the TTY layer at this
point in time.
Tested-by: NTobias Winter <tobias@linuxdingsda.de>
Reviewed-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The usb_serial_port structure had the number field, which was the minor
number for the port, which almost no one really cared about.  They
really wanted the number of the port within the device, which you had to
subtract from the minor of the parent usb_serial_device structure.  To
clean this up, provide the real minor number of the port, and the number
of the port within the serial device separately, as these numbers might
not be related in the future.

Bonus is that this cleans up a lot of logic in the drivers, and saves
lines overall.
Tested-by: NTobias Winter <tobias@linuxdingsda.de>
Reviewed-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

--
 drivers/staging/serqt_usb2/serqt_usb2.c |   21 +++--------
 drivers/usb/serial/ark3116.c            |    2 -
 drivers/usb/serial/bus.c                |    6 +--
 drivers/usb/serial/console.c            |    2 -
 drivers/usb/serial/cp210x.c             |    2 -
 drivers/usb/serial/cypress_m8.c         |    4 +-
 drivers/usb/serial/digi_acceleport.c    |    6 ---
 drivers/usb/serial/f81232.c             |    5 +-
 drivers/usb/serial/garmin_gps.c         |    6 +--
 drivers/usb/serial/io_edgeport.c        |   58 ++++++++++++--------------------
 drivers/usb/serial/io_ti.c              |   21 ++++-------
 drivers/usb/serial/keyspan.c            |   29 +++++++---------
 drivers/usb/serial/metro-usb.c          |    4 +-
 drivers/usb/serial/mos7720.c            |   37 +++++++++-----------
 drivers/usb/serial/mos7840.c            |   52 +++++++++-------------------
 drivers/usb/serial/opticon.c            |    2 -
 drivers/usb/serial/pl2303.c             |    2 -
 drivers/usb/serial/quatech2.c           |    7 +--
 drivers/usb/serial/sierra.c             |    2 -
 drivers/usb/serial/ti_usb_3410_5052.c   |   10 ++---
 drivers/usb/serial/usb-serial.c         |    7 ++-
 drivers/usb/serial/usb_wwan.c           |    2 -
 drivers/usb/serial/whiteheat.c          |   20 +++++------
 include/linux/usb/serial.h              |    6 ++-
 24 files changed, 133 insertions(+), 180 deletions(-)

Remove bogus (and unnecessary) test for serial->dev being NULL in close.

The device is never cleared, and close is never called after a completed
disconnect anyway.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure serial-driver dtr_rts is called with disc_mutex held after
checking the disconnected flag.

Due to a bug in the tty layer, dtr_rts may get called after a device has
been disconnected and the tty-device unregistered. Some drivers have had
individual checks for disconnect to make sure the disconnected interface
was not accessed, but this should really be handled in usb-serial core
(at least until the long-standing tty-bug has been fixed).

Note that the problem has been made more acute with commit 0998d063
("device-core: Ensure drvdata = NULL when no driver is bound") as the
port data is now also NULL when dtr_rts is called resulting in further
oopses.
Reported-by: NChris Ruehl <chris.ruehl@gtsys.com.hk>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

Now, the one where most of tty_port_tty_get gets removed:
tty_flip_buffer_push.

IOW we also closed all the races in drivers not using tty_port_tty_get
at all yet.

Also we move tty_flip_buffer_push declaration from include/linux/tty.h
to include/linux/tty_flip.h to all others while we are changing it
anyway.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

tty_insert_flip_string this time.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove all MODULE_VERSION macros and driver-version information (except
for garmin_gps which uses it in a status reply).

It is the kernel version that matters and not some private version
scheme which rarely even gets updated.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure we do not allocate urbs if we do not have a bulk endpoint.

Legacy code used incorrect assumption to test for bulk endpoints.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix port-data memory leak in usb-serial probe error path by moving port
data allocation to port_probe.

Since commit a1028f0a ("usb: usb_wwan: replace release and disconnect
with a port_remove hook") port data is deallocated in port_remove. This
leaves a possibility for memory leaks if usb-serial probe fails after
attach but before the port in question has been successfully registered.

Note that this patch also fixes two additional memory leaks in the error
path of attach should port initialisation fail for any port as the urbs
were never freed and neither was the data of any of the successfully
initialised ports.

Compile-only tested.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that the dbg() macro is no longer being used in the driver,
the debug module parameter doesn't do anything at all.  So remove
it so as to not confuse people.

CC: "Bjørn Mork" <bjorn@mork.no>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Mauro Carvalho Chehab <mchehab@redhat.com>
CC: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

dbg() was a very old USB-serial-specific macro.
This patch removes it from being used in the
driver and uses dev_dbg() instead.

CC: "Bjørn Mork" <bjorn@mork.no>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Mauro Carvalho Chehab <mchehab@redhat.com>
CC: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We cannot unconditionally access any usb-serial port specific
data from the interface driver.  Both supending and resuming
may happen after the port has been removed and portdata is
freed.

Treat ports with no portdata as closed ports to avoid a NULL
pointer dereference on resume.  No need to kill URBs for
removed ports on suspend, avoiding the same NULL pointer
reference there.
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Doing port specific cleanup in the .port_remove hook is a
lot simpler and safer than doing it in the USB driver
.release or .disconnect methods. The removal of the port
from the usb-serial bus will happen before the USB driver
cleanup, so we must be careful about accessing port specific
driver data from any USB driver functions.

This problem surfaced after the commit

 0998d063 device-core: Ensure drvdata = NULL when no driver is bound

which turned the previous unsafe access into a reliable NULL
pointer dereference.

Fixes the following Oops:

[  243.148471] BUG: unable to handle kernel NULL pointer dereference at           (null)
[  243.148508] IP: [<ffffffffa0468527>] stop_read_write_urbs+0x37/0x80 [usb_wwan]
[  243.148556] PGD 79d60067 PUD 79d61067 PMD 0
[  243.148590] Oops: 0000 [#1] SMP
[  243.148617] Modules linked in: sr_mod cdrom qmi_wwan usbnet option cdc_wdm usb_wwan usbserial usb_storage uas fuse af_packet ip6table_filter ip6_tables iptable_filter ip_tables x_tables tun edd
cpufreq_conservative cpufreq_userspace cpufreq_powersave snd_pcm_oss snd_mixer_oss acpi_cpufreq snd_seq mperf snd_seq_device coretemp arc4 sg hp_wmi sparse_keymap uvcvideo videobuf2_core
videodev videobuf2_vmalloc videobuf2_memops rtl8192ce rtl8192c_common rtlwifi joydev pcspkr microcode mac80211 i2c_i801 lpc_ich r8169 snd_hda_codec_idt cfg80211 snd_hda_intel snd_hda_codec rfkill
snd_hwdep snd_pcm wmi snd_timer ac snd soundcore snd_page_alloc battery uhci_hcd i915 drm_kms_helper drm i2c_algo_bit ehci_hcd thermal usbcore video usb_common button processor thermal_sys
[  243.149007] CPU 1
[  243.149027] Pid: 135, comm: khubd Not tainted 3.5.0-rc7-next-20120720-1-vanilla #1 Hewlett-Packard HP Mini 110-3700                /1584
[  243.149072] RIP: 0010:[<ffffffffa0468527>]  [<ffffffffa0468527>] stop_read_write_urbs+0x37/0x80 [usb_wwan]
[  243.149118] RSP: 0018:ffff880037e75b30  EFLAGS: 00010286
[  243.149133] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88005912aa28
[  243.149150] RDX: ffff88005e95f028 RSI: 0000000000000000 RDI: ffff88005f7c1a10
[  243.149166] RBP: ffff880037e75b60 R08: 0000000000000000 R09: ffffffff812cea90
[  243.149182] R10: 0000000000000000 R11: 0000000000000001 R12: ffff88006539b440
[  243.149198] R13: ffff88006539b440 R14: 0000000000000000 R15: 0000000000000000
[  243.149216] FS:  0000000000000000(0000) GS:ffff88007ee80000(0000) knlGS:0000000000000000
[  243.149233] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[  243.149248] CR2: 0000000000000000 CR3: 0000000079fe0000 CR4: 00000000000007e0
[  243.149264] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  243.149280] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  243.149298] Process khubd (pid: 135, threadinfo ffff880037e74000, task ffff880037d40600)
[  243.149313] Stack:
[  243.149323]  ffff880037e75b40 ffff88006539b440 ffff8800799bc830 ffff88005f7c1800
[  243.149348]  0000000000000001 ffff88006539b448 ffff880037e75b70 ffffffffa04685e9
[  243.149371]  ffff880037e75bc0 ffffffffa0473765 ffff880037354988 ffff88007b594800
[  243.149395] Call Trace:
[  243.149419]  [<ffffffffa04685e9>] usb_wwan_disconnect+0x9/0x10 [usb_wwan]
[  243.149447]  [<ffffffffa0473765>] usb_serial_disconnect+0xd5/0x120 [usbserial]
[  243.149511]  [<ffffffffa0046b48>] usb_unbind_interface+0x58/0x1a0 [usbcore]
[  243.149545]  [<ffffffff8139ebd7>] __device_release_driver+0x77/0xe0
[  243.149567]  [<ffffffff8139ec67>] device_release_driver+0x27/0x40
[  243.149587]  [<ffffffff8139e5cf>] bus_remove_device+0xdf/0x150
[  243.149608]  [<ffffffff8139bc78>] device_del+0x118/0x1a0
[  243.149661]  [<ffffffffa0044590>] usb_disable_device+0xb0/0x280 [usbcore]
[  243.149718]  [<ffffffffa003c6fd>] usb_disconnect+0x9d/0x140 [usbcore]
[  243.149770]  [<ffffffffa003da7d>] hub_port_connect_change+0xad/0x8a0 [usbcore]
[  243.149825]  [<ffffffffa0043bf5>] ? usb_control_msg+0xe5/0x110 [usbcore]
[  243.149878]  [<ffffffffa003e6e3>] hub_events+0x473/0x760 [usbcore]
[  243.149931]  [<ffffffffa003ea05>] hub_thread+0x35/0x1d0 [usbcore]
[  243.149955]  [<ffffffff81061960>] ? add_wait_queue+0x60/0x60
[  243.150004]  [<ffffffffa003e9d0>] ? hub_events+0x760/0x760 [usbcore]
[  243.150026]  [<ffffffff8106133e>] kthread+0x8e/0xa0
[  243.150047]  [<ffffffff8157ec04>] kernel_thread_helper+0x4/0x10
[  243.150068]  [<ffffffff810612b0>] ? flush_kthread_work+0x120/0x120
[  243.150088]  [<ffffffff8157ec00>] ? gs_change+0xb/0xb
[  243.150101] Code: fd 41 54 53 48 83 ec 08 80 7f 1a 00 74 57 49 89 fc 31 db 90 49 8b 7c 24 20 45 31 f6 48 81 c7 10 02 00 00 e8 bc 64 f3 e0 49 89 c7 <4b> 8b 3c 37 49 83 c6 08 e8 4c a5 bd ff 49 83 fe 20
75 ed 45 30
[  243.150257] RIP  [<ffffffffa0468527>] stop_read_write_urbs+0x37/0x80 [usb_wwan]
[  243.150282]  RSP <ffff880037e75b30>
[  243.150294] CR2: 0000000000000000
[  243.177170] ---[ end trace fba433d9015ffb8c ]---
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Reported-by: NThomas Schäfer <tschaefer@t-online.de>
Suggested-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This will let us sort out a whole pile of tty related races. The
alternative would be to keep points and refcount the termios objects.
However
1. They are tiny anyway
2. Many devices don't use the stored copies
3. We can remove a pty special case
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

dbg() was used a lot a long time ago to trace code flow.  Now that we have
ftrace, this isn't needed at all, so remove these calls.

CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Alan Stern <stern@rowland.harvard.edu>
CC: Mauro Carvalho Chehab <mchehab@redhat.com>
CC: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>