Commit graph

1600 commits

Author SHA1 Message Date
Michael Spang
d09a7308e9 serial: samsung: Restore IRQ mask during noirq resume
This closes a window where the system may hang in resume as soon as the
UART interrupt is enabled and before the mask is restored. The hang occurs
because the driver can't handle IRQs it thinks are masked.

Signed-off-by: Michael Spang <spang@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-28 16:04:19 -07:00
Tomasz Figa
b6ad293555 tty: serial: samsung: Disable interrupts in a suspend-friendly way
Since the interrupt mask register is not preserved across system suspend
and it defaults to all interrupts enabled, it is not enough to disable
UART interrupt.

This patch adds free_irq to port shutdown and mask setting to port
startup to handle IRQ disabling in a suspend-friendly way. In addition,
a bug caused by multiple request_irq calls in port startup callback is
fixed.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-28 16:03:54 -07:00
Karthik Manamcheri
cfcec52e97 serial: 8250: Make SERIAL_8250_RUNTIME_UARTS work correctly
Consider a situation where I have an ARM based system
and therefore no legacy ports. Say, I have two
memory-mapped ports. I use device tree to describe the
ports. What would be the config options I set so that
I get only the two ports in my system? I do not want
legacy ports being created automatically and I want
it to be flexible enough that it creates the devices
based only on the device tree. I expected setting
SERIAL_8250_RUNTIME_UARTS = 0 to work because the
description said, "Set this to the maximum number of
serial ports you want the kernel to register at boot
time." Unfortunately, even though SERIAL_8250_NR_UARTS
was set to the default value of 4, I did not get any device
nodes (because SERIAL_8250_RUNTIME_UARTS was 0). This
is what this change is addressing.

SERIAL_8250_NR_UARTS controls the maximum number of ports
you can support. SERIAL_8250_RUNTIME_UARTS specifies the
number of ports you want to create automatically for legacy
ports at boot time. All other ports will be created
when serial8250_register_port is called (and if does not exceed
the total number of supported ports as specified by
SERIAL_8250_NR_UARTS).

Signed-off-by: Karthik Manamcheri <karthik.manamcheri@ni.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-28 15:50:40 -07:00
Paul Bolle
65c1b12b45 serial: 8250: remove a few lines of dead code
Support for the WindRiver SBC8560 board was removed in v3.6. But there
are still a few lines depending on its obsolete Kconfig macro. Remove
these now.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-25 16:36:48 -07:00
Heikki Krogerus
b0b8c84cf5 serial: of_serial: Handle auto-flow-control property
Automatic Flow Control capability is not tied to this
property. This is only one way of detecting it. The property
is limited to be used only with 8250 driver.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-25 16:36:48 -07:00
Changlong Xie
44a459fd83 tty: tty_vhangup_session can be static
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Peter Hurley <peter@hurleysoftware.com>

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-25 14:07:34 -07:00
Steffen Trumtrar
30215c3b8f serial: xilinx_uartps: remove superfluous IDR write
The datesheet clearly states, that writing low bits to the
XUARTPS_IDR register have no effect. Remove the write.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-25 14:06:45 -07:00
Paul Bolle
b250a6b001 serial: sh-sci: remove obsolete Kconfig macros
Support for SH7367 and SH7377 got removed in v3.8. Now remove their
last Kconfig macros.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-25 14:06:45 -07:00
Heikki Krogerus
9f1ca068ea serial: of_serial: Handle fifo-size property
This will reduce the need for extra types in 8250.c just
in case the fifo size differs from the standard.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-25 14:06:44 -07:00
Heikki Krogerus
6a3f45dccf serial: 8250: Allow probe drivers to ignore tx_loadsz
In most cases the tx_loadsz is the same as fifosize. This
will store the fifosize in it if it was not separately
delivered from the driver.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-25 14:06:44 -07:00
Greg Kroah-Hartman
23a376f98c Merge 3.9-rc3 into tty-next 2013-03-21 16:07:34 -07:00
Zhang Yanfei
8358f6242d driver: tty: vt: remove cast for kmalloc return value
remove cast for kmalloc return value.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 17:09:37 -07:00
Zhang Yanfei
b9a129f481 driver: tty: serial: remove cast for kzalloc return value
remove cast for kzalloc return value.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 17:09:37 -07:00
Jiri Slaby
7bbe08d6b8 TTY: serial, stop accessing potential NULLs
The following commits:
* 6732c8bb86 (TTY: switch
  tty_schedule_flip)
* 2e124b4a39 (TTY: switch
  tty_flip_buffer_push)
* 05c7cd3990 (TTY: switch
  tty_insert_flip_string)
* 92a19f9cec (TTY: switch
  tty_insert_flip_char)
* 227434f898 (TTY: switch
  tty_buffer_request_room to tty_port)

introduced a potential NULL dereference to some drivers. In
particular, when the device is used as a console, incoming bytes can
kill the box. This is caused by removed checks for TTY against NULL.

It happened because it was unclear to me why the checks were there. I
assumed them superfluous because the interrupts were unbound or
otherwise stopped. But this is not the case for consoles for these
drivers, as was pointed out by David Miller.

Now, this patch re-introduces the checks (at this point we check
port->state, not the tty proper, as we do not care about tty pointers
anymore). For both of the drivers, we place the check below the
handling of break signal so that sysrq can actually work. (One needs
to issue a break and then sysrq key within the following 5 seconds.)

We do not change sc26xx, sunhv, and sunsu here because they behave the
same as before.  People having that hardware should fix the driver
eventually, however. They always could unconditionally dereference tty
in receive_chars, port->state in uart_handle_dcd_change, and
up->port.state->port.tty.

There is perhaps more to fix in all those drivers, but they are at
least in a state they were before.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: sparclinux@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 17:09:37 -07:00
Peter Hurley
e7f3880cd9 tty: Fix recursive deadlock in tty_perform_flush()
tty_perform_flush() can deadlock when called while holding
a line discipline reference. By definition, all ldisc drivers
hold a ldisc reference, so calls originating from ldisc drivers
must not block for a ldisc reference.

The deadlock can occur when:
  CPU 0                    |  CPU 1
                           |
tty_ldisc_ref(tty)         |
....                       | <line discipline halted>
tty_ldisc_ref_wait(tty)    |
                           |

CPU 0 cannot progess because it cannot obtain an ldisc reference
with the line discipline has been halted (thus no new references
are granted).
CPU 1 cannot progress because an outstanding ldisc reference
has not been released.

An in-tree call-tree audit of tty_perform_flush() [1] shows 5
ldisc drivers calling tty_perform_flush() indirectly via
n_tty_ioctl_helper() and 2 ldisc drivers calling directly.
A single tty driver safely uses the function.

[1]
Recursive usage:

/* These functions are line discipline ioctls and thus
 * recursive wrt line discipline references */

tty_perform_flush() - ./drivers/tty/tty_ioctl.c
    n_tty_ioctl_helper()
        hci_uart_tty_ioctl(default) - drivers/bluetooth/hci_ldisc.c (N_HCI)
        n_hdlc_tty_ioctl(default) - drivers/tty/n_hdlc.c (N_HDLC)
        gsmld_ioctl(default) - drivers/tty/n_gsm.c (N_GSM0710)
        n_tty_ioctl(default) - drivers/tty/n_tty.c (N_TTY)
        gigaset_tty_ioctl(default) - drivers/isdn/gigaset/ser-gigaset.c (N_GIGASET_M101)
    ppp_synctty_ioctl(TCFLSH) - drivers/net/ppp/pps_synctty.c
    ppp_asynctty_ioctl(TCFLSH) - drivers/net/ppp/ppp_async.c

Non-recursive use:

tty_perform_flush() - drivers/tty/tty_ioctl.c
    ipw_ioctl(TCFLSH) - drivers/tty/ipwireless/tty.c
       /* This function is a tty i/o ioctl method, which
        * is invoked by tty_ioctl() */

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:52:24 -07:00
Peter Hurley
be3971166d tty: Remove redundant tty_wait_until_sent()
tty_ioctl() already waits until sent.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:48:42 -07:00
Peter Hurley
734de249fb tty: Locate get/put ldisc functions together
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:48:42 -07:00
Peter Hurley
f48070457c tty: Fold one-line assign function into callers
Now that tty_ldisc_assign() is a one-line file-scoped function,
remove it and perform the simple assignment at its call sites.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:48:42 -07:00
Peter Hurley
16759f6cd8 tty: Document unsafe ldisc reference acquire
Merge get_ldisc() into its only call site.
Note how, after merging, the unsafe acquire of an ldisc reference
is obvious.

   CPU 0 in tty_ldisc_try()         |  CPU 1 in tty_ldisc_halt()
                                    |
test_bit(TTY_LDISC, &tty_flags)     |
if (true)                           |  clear_bit(TTY_LDISC, &tty_flags)
  tty->ldisc != 0?                  |  atomic_read(&tty->ldisc->users)
  if (true)                         |  ret_val == 1?
    atomic_inc(&tty->ldisc->users)  |  if (false)
                                    |    wait
                                    |
<goes on assuming safe ldisc use>   |  <doesn't wait - proceeds w/ close>
                                    |

The spin lock in tty_ldisc_try() does nothing wrt synchronizing
the ldisc halt since it's not acquired as part of halting.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:48:42 -07:00
Peter Hurley
ebc9baed42 tty: Separate release semantics of ldisc reference
tty_ldisc_ref()/tty_ldisc_unref() have usage semantics
equivalent to down_read_trylock()/up_read(). Only
callers of tty_ldisc_put() are performing the additional
operations necessary for proper ldisc teardown, and then only
after ensuring no outstanding 'read lock' remains.

Thus, tty_ldisc_unref() should never be the last reference;
WARN if it is. Conversely, tty_ldisc_put() should never be
destructing if the use count != 1.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:48:42 -07:00
Peter Hurley
8842dda236 tty: Don't protect atomic operation with mutex
test_bit() is already atomic; drop mutex lock/unlock.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:46:31 -07:00
Peter Hurley
fc575ee6ea tty: Add ldisc hangup debug messages
Expected typical debug log:
[  582.721965] tty_open: opening pts3...
[  582.721970] tty_open: opening pts3...
[  582.721977] tty_release: pts3 (tty count=3)...
[  582.721980] tty_release: ptm3 (tty count=1)...
[  582.722015] pts3 vhangup...
[  582.722020] tty_ldisc_hangup: pts3: closing ldisc: ffff88007a920540
[  582.724128] tty_release: pts3 (tty count=2)...
[  582.724217] tty_ldisc_hangup: pts3: re-opened ldisc: ffff88007a920580
[  582.724221] tty_release: ptm3: final close
[  582.724234] tty_ldisc_release: ptm3: closing ldisc: ffff88007a920a80
[  582.724238] tty_ldisc_release: ptm3: ldisc closed
[  582.724241] tty_release: ptm3: freeing structure...
[  582.724741] tty_open: opening pts3...

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:46:30 -07:00
Peter Hurley
96433d104a tty: Bracket ldisc release with TTY_DEBUG_HANGUP messages
Expected typical log output:
[    2.437211] tty_open: opening pts1...
[    2.443376] tty_open: opening pts5...
[    2.447830] tty_release: ptm0 (tty count=1)...
[    2.447849] pts0 vhangup...
[    2.447865] tty_release: ptm0: final close
[    2.447876] tty_release: ptm0: freeing structure...
[    2.451634] tty_release: tty1 (tty count=1)...
[    2.451638] tty_release: tty1: final close
[    2.451654] tty_release: tty1: freeing structure...
[    2.452505] tty_release: pts5 (tty count=2)...
[    2.453029] tty_open: opening pts0...

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:46:30 -07:00
Peter Hurley
c878524174 tty: Fix 'deferred reopen' ldisc comment
This comment is a victim of code migration from
"tty: Fix the ldisc hangup race"; re-parent it.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:44:02 -07:00
Peter Hurley
a2965b7bee tty: Make core responsible for synchronizing its work
The tty core relies on the ldisc layer for synchronizing destruction
of the tty. Instead, the final tty release must wait for any pending tty
work to complete prior to tty destruction.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:44:02 -07:00
Peter Hurley
4f98d46751 tty: Complete ownership transfer of flip buffers
Waiting for buffer work to complete is not required for safely
performing changes to the line discipline, once the line discipline
is halted. The buffer work routine, flush_to_ldisc(), will be
unable to acquire an ldisc ref and all existing references were
waited until released (so it can't already have one).

Ensure running buffer work which may reference the soon-to-be-gone
tty completes and any buffer work running after this point retrieves
a NULL tty.

Also, ensure all buffer work is cancelled on port destruction.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:44:02 -07:00
Peter Hurley
d912156605 tty: Don't reenable already enabled ldisc
tty_ldisc_hangup() guarantees the ldisc is enabled (or that there
is no ldisc). Since __tty_hangup() was the only user, re-define
tty_ldisc_enable() in file-scope.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:44:02 -07:00
Peter Hurley
b66f4fa509 n_tty: Fully initialize ldisc before restarting buffer work
Buffer work may already be pending when the n_tty ldisc is re-opened,
eg., when setting the ldisc (via TIOCSETD ioctl) and when hanging up
the tty. Since n_tty_set_room() may restart buffer work, first ensure
the ldisc is completely initialized.

Factor n_tty_set_room() out of reset_buffer_flags() (only 2 callers)
and reorganize n_tty_open() to set termios last; buffer work will
be restarted there if necessary, after the char_map is properly
initialized.

Fixes this WARNING:

[  549.561769] ------------[ cut here ]------------
[  549.598755] WARNING: at drivers/tty/n_tty.c:160 n_tty_set_room+0xff/0x130()
[  549.604058] scheduling buffer work for halted ldisc
[  549.607741] Pid: 9417, comm: trinity-child28 Tainted: G      D W 3.7.0-next-20121217-sasha-00023-g8689ef9 #219
[  549.652580] Call Trace:
[  549.662754]  [<ffffffff81c432cf>] ? n_tty_set_room+0xff/0x130
[  549.665458]  [<ffffffff8110cae7>] warn_slowpath_common+0x87/0xb0
[  549.668257]  [<ffffffff8110cb71>] warn_slowpath_fmt+0x41/0x50
[  549.671007]  [<ffffffff81c432cf>] n_tty_set_room+0xff/0x130
[  549.673268]  [<ffffffff81c44597>] reset_buffer_flags+0x137/0x150
[  549.675607]  [<ffffffff81c45b71>] n_tty_open+0x131/0x1c0
[  549.677699]  [<ffffffff81c47824>] tty_ldisc_open.isra.5+0x54/0x70
[  549.680147]  [<ffffffff81c482bf>] tty_ldisc_hangup+0x11f/0x1e0
[  549.682409]  [<ffffffff81c3fa17>] __tty_hangup+0x137/0x440
[  549.684634]  [<ffffffff81c3fd49>] tty_vhangup+0x9/0x10
[  549.686443]  [<ffffffff81c4a42c>] pty_close+0x14c/0x160
[  549.688446]  [<ffffffff81c41225>] tty_release+0xd5/0x490
[  549.690460]  [<ffffffff8127d8a2>] __fput+0x122/0x250
[  549.692577]  [<ffffffff8127d9d9>] ____fput+0x9/0x10
[  549.694534]  [<ffffffff811348c2>] task_work_run+0xb2/0xf0
[  549.696349]  [<ffffffff81113c6d>] do_exit+0x36d/0x580
[  549.698286]  [<ffffffff8107d964>] ? syscall_trace_enter+0x24/0x2e0
[  549.702729]  [<ffffffff81113f4a>] do_group_exit+0x8a/0xc0
[  549.706775]  [<ffffffff81113f92>] sys_exit_group+0x12/0x20
[  549.711088]  [<ffffffff83cfab18>] tracesys+0xe1/0xe6
[  549.728001] ---[ end trace 73eb41728f11f87e ]---

Reported-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:44:01 -07:00
Peter Hurley
25518c68b3 n_tty: Correct unthrottle-with-buffer-flush comments
The driver is no longer unthrottled on buffer reset, so remove
comments that claim it is.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:38:58 -07:00
Peter Hurley
977066e758 tty: Wait for SAK work before waiting for hangup work
SAK work may schedule hangup work (if TTY_SOFT_SAK is defined), thus
SAK work must be flushed before hangup work.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:38:58 -07:00
Peter Hurley
f4cf7a3845 tty: Halt both ldiscs concurrently
The pty driver does not obtain an ldisc reference to the linked
tty when writing. When the ldiscs are sequentially halted, it
is possible for one ldisc to be halted, and before the second
ldisc can be halted, a concurrent write schedules buffer work on
the first ldisc. This can lead to an access-after-free error when
the scheduled buffer work starts on the closed ldisc.

Prevent subsequent use after halt by performing each stage
of the halt on both ttys.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:38:58 -07:00
Peter Hurley
cf52847658 tty: Strengthen no-subsequent-use guarantee of tty_ldisc_halt()
In preparation for destructing and freeing the tty, the line discipline
must first be brought to an inactive state before it can be destructed.
This line discipline shutdown must:
 - disallow new users of the ldisc
 - wait for existing ldisc users to finish
 - only then, cancel/flush their pending/running work

Factor tty_ldisc_wait_idle() from tty_set_ldisc() and tty_ldisc_kill()
to ensure this shutdown order.

Failure to provide this guarantee can result in scheduled work
running after the tty has already been freed, as indicated in the
following log message:

[   88.331234] WARNING: at drivers/tty/tty_buffer.c:435 flush_to_ldisc+0x194/0x1d0()
[   88.334505] Hardware name: Bochs
[   88.335618] tty is bad=-1
[   88.335703] Modules linked in: netconsole configfs bnep rfcomm bluetooth ......
[   88.345272] Pid: 39, comm: kworker/1:1 Tainted: G        W    3.7.0-next-20121129+ttydebug-xeon #20121129+ttydebug
[   88.347736] Call Trace:
[   88.349024]  [<ffffffff81058aff>] warn_slowpath_common+0x7f/0xc0
[   88.350383]  [<ffffffff81058bf6>] warn_slowpath_fmt+0x46/0x50
[   88.351745]  [<ffffffff81432bd4>] flush_to_ldisc+0x194/0x1d0
[   88.353047]  [<ffffffff816f7fe1>] ? _raw_spin_unlock_irq+0x21/0x50
[   88.354190]  [<ffffffff8108a809>] ? finish_task_switch+0x49/0xe0
[   88.355436]  [<ffffffff81077ad1>] process_one_work+0x121/0x490
[   88.357674]  [<ffffffff81432a40>] ? __tty_buffer_flush+0x90/0x90
[   88.358954]  [<ffffffff81078c84>] worker_thread+0x164/0x3e0
[   88.360247]  [<ffffffff81078b20>] ? manage_workers+0x120/0x120
[   88.361282]  [<ffffffff8107e230>] kthread+0xc0/0xd0
[   88.362284]  [<ffffffff816f0000>] ? cmos_do_probe+0x2eb/0x3bf
[   88.363391]  [<ffffffff8107e170>] ? flush_kthread_worker+0xb0/0xb0
[   88.364797]  [<ffffffff816fff6c>] ret_from_fork+0x7c/0xb0
[   88.366087]  [<ffffffff8107e170>] ? flush_kthread_worker+0xb0/0xb0
[   88.367266] ---[ end trace 453a7c9f38fbfec0 ]---

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:38:58 -07:00
Peter Hurley
11cf48eab2 tty: Relocate tty_ldisc_halt() to avoid forward declaration
tty_ldisc_halt() will use the file-scoped function, tty_ldisc_wait_idle(),
in the following patch.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:38:58 -07:00
Peter Hurley
76bc35e78f tty: Fix ldisc halt sequence on hangup
Flip buffer work cannot be cancelled until all outstanding ldisc
references have been released. Convert the ldisc ref wait into
a full ldisc halt with buffer work cancellation.

Note that the legacy mutex is not held while cancelling.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Peter Hurley
2276ad9765 tty: Remove unnecessary re-test of ldisc ref count
Since the tty->ldisc is prevented from being changed by tty_set_ldisc()
when a tty is being hung up, re-testing the ldisc user count is
unnecessary -- ie, it cannot be a different ldisc and the user count
cannot have increased (assuming the caller meets the precondition that
TTY_LDISC flag is cleared)

Removal of the 'early-out' locking optimization is necessary for
the subsequent patch 'tty: Fix ldisc halt sequence on hangup'.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Peter Hurley
168942c9fa tty: Refactor wait for ldisc refs out of tty_ldisc_hangup()
Refactor tty_ldisc_hangup() to extract standalone function,
tty_ldisc_hangup_wait_idle(), to wait for ldisc references
to be released.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Peter Hurley
79901317ce n_tty: Don't flush buffer when closing ldisc
A buffer flush is both undesirable and unnecessary when the ldisc
is closing. A buffer flush performs the following:
 1. resets ldisc data fields to their initial state
 2. resets tty->receive_room to indicate more data can be sent
 3. schedules buffer work to receive more data
 4. signals a buffer flush has happened to linked pty in packet mode

Since the ldisc has been halted and the tty may soon be destructed,
buffer work must not be scheduled as that work might access
an invalid tty and ldisc state. Also, the ldisc read buffer is about
to be freed, so that's pointless.

Resetting the ldisc data fields is pointless as well since that
structure is about to be freed.

Resetting tty->receive_room is unnecessary, as it will be properly
reset if a new ldisc is reopened. Besides, resetting the original
receive_room value would be wrong since the read buffer will be
gone.

Since the packet mode flush is observable from userspace, this
behavior has been preserved.

The test jig originally authored by Ilya Zykov <ilya@ilyx.ru> and
signed off by him is included below. The test jig prompts the
following warnings which this patch fixes.

[   38.051111] ------------[ cut here ]------------
[   38.052113] WARNING: at drivers/tty/n_tty.c:160 n_tty_set_room.part.6+0x8b/0xa0()
[   38.053916] Hardware name: Bochs
[   38.054819] Modules linked in: netconsole configfs bnep rfcomm bluetooth parport_pc ppdev snd_hda_intel snd_hda_codec
snd_hwdep snd_pcm snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq psmouse snd_timer serio_raw mac_hid snd_seq_device
snd microcode lp parport virtio_balloon soundcore i2c_piix4 snd_page_alloc floppy 8139too 8139cp
[   38.059704] Pid: 1564, comm: pty_kill Tainted: G        W    3.7.0-next-20121130+ttydebug-xeon #20121130+ttydebug
[   38.061578] Call Trace:
[   38.062491]  [<ffffffff81058b4f>] warn_slowpath_common+0x7f/0xc0
[   38.063448]  [<ffffffff81058baa>] warn_slowpath_null+0x1a/0x20
[   38.064439]  [<ffffffff8142dc2b>] n_tty_set_room.part.6+0x8b/0xa0
[   38.065381]  [<ffffffff8142dc82>] n_tty_set_room+0x42/0x80
[   38.066323]  [<ffffffff8142e6f2>] reset_buffer_flags+0x102/0x160
[   38.077508]  [<ffffffff8142e76d>] n_tty_flush_buffer+0x1d/0x90
[   38.078782]  [<ffffffff81046569>] ? default_spin_lock_flags+0x9/0x10
[   38.079734]  [<ffffffff8142e804>] n_tty_close+0x24/0x60
[   38.080730]  [<ffffffff81431b61>] tty_ldisc_close.isra.2+0x41/0x60
[   38.081680]  [<ffffffff81431bbb>] tty_ldisc_kill+0x3b/0x80
[   38.082618]  [<ffffffff81432a07>] tty_ldisc_release+0x77/0xe0
[   38.083549]  [<ffffffff8142b781>] tty_release+0x451/0x4d0
[   38.084525]  [<ffffffff811950be>] __fput+0xae/0x230
[   38.085472]  [<ffffffff8119524e>] ____fput+0xe/0x10
[   38.086401]  [<ffffffff8107aa88>] task_work_run+0xc8/0xf0
[   38.087334]  [<ffffffff8105ea56>] do_exit+0x196/0x4b0
[   38.088304]  [<ffffffff8106c77b>] ? __dequeue_signal+0x6b/0xb0
[   38.089240]  [<ffffffff8105ef34>] do_group_exit+0x44/0xa0
[   38.090182]  [<ffffffff8106f43d>] get_signal_to_deliver+0x20d/0x4e0
[   38.091125]  [<ffffffff81016979>] do_signal+0x29/0x130
[   38.092096]  [<ffffffff81431a9e>] ? tty_ldisc_deref+0xe/0x10
[   38.093030]  [<ffffffff8142a317>] ? tty_write+0xb7/0xf0
[   38.093976]  [<ffffffff81193f53>] ? vfs_write+0xb3/0x180
[   38.094904]  [<ffffffff81016b20>] do_notify_resume+0x80/0xc0
[   38.095830]  [<ffffffff81700492>] int_signal+0x12/0x17
[   38.096788] ---[ end trace 5f6f7a9651cd999b ]---

[ 2730.570602] ------------[ cut here ]------------
[ 2730.572130] WARNING: at drivers/tty/n_tty.c:160 n_tty_set_room+0x107/0x140()
[ 2730.574904] scheduling buffer work for halted ldisc
[ 2730.578303] Pid: 9691, comm: trinity-child15 Tainted: G        W 3.7.0-rc8-next-20121205-sasha-00023-g59f0d85 #207
[ 2730.588694] Call Trace:
[ 2730.590486]  [<ffffffff81c41d77>] ? n_tty_set_room+0x107/0x140
[ 2730.592559]  [<ffffffff8110c827>] warn_slowpath_common+0x87/0xb0
[ 2730.595317]  [<ffffffff8110c8b1>] warn_slowpath_fmt+0x41/0x50
[ 2730.599186]  [<ffffffff81c41d77>] n_tty_set_room+0x107/0x140
[ 2730.603141]  [<ffffffff81c42fe7>] reset_buffer_flags+0x137/0x150
[ 2730.607166]  [<ffffffff81c43018>] n_tty_flush_buffer+0x18/0x90
[ 2730.610123]  [<ffffffff81c430af>] n_tty_close+0x1f/0x60
[ 2730.612068]  [<ffffffff81c461f2>] tty_ldisc_close.isra.4+0x52/0x60
[ 2730.614078]  [<ffffffff81c462ab>] tty_ldisc_reinit+0x3b/0x70
[ 2730.615891]  [<ffffffff81c46db2>] tty_ldisc_hangup+0x102/0x1e0
[ 2730.617780]  [<ffffffff81c3e537>] __tty_hangup+0x137/0x440
[ 2730.619547]  [<ffffffff81c3e869>] tty_vhangup+0x9/0x10
[ 2730.621266]  [<ffffffff81c48f1c>] pty_close+0x14c/0x160
[ 2730.622952]  [<ffffffff81c3fd45>] tty_release+0xd5/0x490
[ 2730.624674]  [<ffffffff8127fbe2>] __fput+0x122/0x250
[ 2730.626195]  [<ffffffff8127fd19>] ____fput+0x9/0x10
[ 2730.627758]  [<ffffffff81134602>] task_work_run+0xb2/0xf0
[ 2730.629491]  [<ffffffff811139ad>] do_exit+0x36d/0x580
[ 2730.631159]  [<ffffffff81113c8a>] do_group_exit+0x8a/0xc0
[ 2730.632819]  [<ffffffff81127351>] get_signal_to_deliver+0x501/0x5b0
[ 2730.634758]  [<ffffffff8106de34>] do_signal+0x24/0x100
[ 2730.636412]  [<ffffffff81204865>] ? user_exit+0xa5/0xd0
[ 2730.638078]  [<ffffffff81183cd8>] ? trace_hardirqs_on_caller+0x118/0x140
[ 2730.640279]  [<ffffffff81183d0d>] ? trace_hardirqs_on+0xd/0x10
[ 2730.642164]  [<ffffffff8106df78>] do_notify_resume+0x48/0xa0
[ 2730.643966]  [<ffffffff83cdff6a>] int_signal+0x12/0x17
[ 2730.645672] ---[ end trace a40d53149c07fce0 ]---

/*
 * pty_thrash.c
 *
 * Based on original test jig by Ilya Zykov <ilya@ilyx.ru>
 *
 * Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
 * Signed-off-by: Ilya Zykov <ilya@ilyx.ru>
 */

static int fd;

static void error_exit(char *f, ...)
{
        va_list va;

        va_start(va, f);
        vprintf(f, va);
        printf(": %s\n", strerror(errno));
        va_end(va);

        if (fd >= 0)
                close(fd);

        exit(EXIT_FAILURE);
}

int main(int argc, char *argv[]) {
        int parent;
        char pts_name[24];
        int ptn, unlock;

        while (1) {

                fd = open("/dev/ptmx", O_RDWR);
                if (fd < 0)
                        error_exit("opening pty master");
                unlock = 0;
                if (ioctl(fd, TIOCSPTLCK, &unlock) < 0)
                        error_exit("unlocking pty pair");
                if (ioctl(fd, TIOCGPTN, &ptn) < 0)
                        error_exit("getting pty #");
                snprintf(pts_name, sizeof(pts_name), "/dev/pts/%d", ptn);

                child_id = fork();
                if (child_id == -1)
                        error_exit("forking child");

                if (parent) {
                        int err, id, status;
                        char buf[128];
                        int n;

                        n = read(fd, buf, sizeof(buf));
                        if (n < 0)
                                error_exit("master reading");
                        printf("%.*s\n", n-1, buf);

                        close(fd);

                        err = kill(child_id, SIGKILL);
                        if (err < 0)
                                error_exit("killing child");
                        id = waitpid(child_id, &status, 0);
                        if (id < 0 || id != child_id)
                                error_exit("waiting for child");

                } else { /* Child */

                        close(fd);
                        printf("Test cycle on slave pty %s\n", pts_name);
                        fd = open(pts_name, O_RDWR);
                        if (fd < 0)
                                error_exit("opening pty slave");

                        while (1) {
                                char pattern[] = "test\n";
                                if (write(fd, pattern, strlen(pattern)) < 0)
                                        error_exit("slave writing");
                        }

                }
        }

        /* never gets here */
        return 0;
}

Reported-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Peter Hurley
a30737ab7d n_tty: Factor packet mode status change for reuse
Factor the packet mode status change from n_tty_flush_buffer
for use by follow-on patch.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Peter Hurley
21622939fc tty: Add diagnostic for halted line discipline
Flip buffer work must not be scheduled by the line discipline
after the line discipline has been halted; issue warning.

Note: drivers can still schedule flip buffer work.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Lars-Peter Clausen
91debb0383 tty: ifx6x60: Remove unused suspend/resume callbacks
The ifx6x60 driver implements both legacy suspend/resume callbacks and
dev_pm_ops. The SPI core is going to ignore legacy suspend/resume
callbacks if a driver implements dev_pm_ops. Since the legacy suspend/resume
callbacks are empty in this case it is safe to just remove them.

Cc: Bi Chao <chao.bi@intel.com>
Cc: Chen Jun <jun.d.chen@intel.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:29:29 -07:00
Lars-Peter Clausen
c2ee91bd66 tty: mrst_max3110: Use dev_pm_ops
Use dev_pm_ops instead of the deprecated legacy suspend/resume for the
mrst_max3110 driver.

Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:29:29 -07:00
Lars-Peter Clausen
b7df719db7 tty: max310x: Use dev_pm_ops
Use dev_pm_ops instead of the deprecated legacy suspend/resume for the
max310x driver.

Cc: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:29:29 -07:00
Lars-Peter Clausen
c47ddc26db tty: max3100: Use dev_pm_ops
Use dev_pm_ops instead of the deprecated legacy suspend/resume for the
max3100 driver.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:29:29 -07:00
Johan Hovold
0b2588cadf TTY: fix close of uninitialised ports
Make sure we do not make tty-driver callbacks or wait for port to drain
on uninitialised ports (e.g. when open failed) in
tty_port_close_start().

No callback, such as flush_buffer or wait_until_sent, needs to be made
on a port that has never been opened. Neither does it make much sense to
add drain delay for an uninitialised port.

Currently a drain delay of up to two seconds could be added when a tty
fails to open.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:54 -07:00
Johan Hovold
b74414f5f3 TTY: clean up port drain-delay handling
Move port drain-delay handling to a separate function.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:54 -07:00
Johan Hovold
957dacaee5 TTY: fix DTR not being dropped on hang up
Move HUPCL handling to port shutdown so that DTR is dropped also on hang
up (tty_port_close is a noop for hung-up ports).

Also do not try to drop DTR for uninitialised ports where it has never
been raised (e.g. after a failed open).

Note that this is also the current behaviour of serial-core.

Nine drivers currently call tty_port_close_start directly (rather than
through tty_port_close) and seven of them lower DTR as part of their
close (if the port has been initialised). Fixup the remaining two
drivers so that it continues to be lowered also on normal (non-HUP)
close. [ Note that most of those other seven drivers did not expect DTR
to have been dropped by tty_port_close_start in the first place. ]

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:53 -07:00
Johan Hovold
e584a02cf5 TTY: fix DTR being raised on hang up
Make sure to check ASYNC_INITIALISED before raising DTR when waking up
from blocked open in tty_port_block_til_ready.

Currently DTR could get raised at hang up as a blocked process would
raise DTR unconditionally before checking for hang up and returning.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:53 -07:00
Johan Hovold
31ca020b57 TTY: wake up processes last at hangup
Move wake up of processes on blocked-open and modem-status wait queues
to after port shutdown at hangup.

This way the woken up processes can use the ASYNC_INITIALIZED flag to
detect port shutdown.

Note that this is the order currently used by serial-core.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:53 -07:00
Johan Hovold
8bde9658a0 TTY: clean up port shutdown
Untangle port-shutdown logic and make sure the initialised flag is
always cleared for non-console ports.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:53 -07:00
Jiri Slaby
b12d8dc2db crisv10: use counts from tty_port
The same as flags, convert to using open/close counts from tty_port.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:26:33 -07:00