linux-stable.git/drivers/tty/tty_ldisc.c, branch v4.15

Merge tag 'tty-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2017-11-14T05:05:31+00:00

Pull tty/serial updates from Greg KH:
 "Here is the big tty/serial driver pull request for 4.15-rc1.

  Lots of serial driver updates in here, some small vt cleanups, and a
  raft of SPDX and license boilerplate cleanups, messing up the diffstat
  a bit.

  Nothing major, with no realy functional changes except better hardware
  support for some platforms.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (110 commits)
  tty: ehv_bytechan: fix spelling mistake
  tty: serial: meson: allow baud-rates lower than 9600
  serial: 8250_fintek: Fix crash with baud rate B0
  serial: 8250_fintek: Disable delays for ports != 0
  serial: 8250_fintek: Return -EINVAL on invalid configuration
  tty: Remove redundant license text
  tty: serdev: Remove redundant license text
  tty: hvc: Remove redundant license text
  tty: serial: Remove redundant license text
  tty: add SPDX identifiers to all remaining files in drivers/tty/
  tty: serial: jsm: remove redundant pointer ts
  tty: serial: jsm: add space before the open parenthesis '('
  tty: serial: jsm: fix coding style
  tty: serial: jsm: delete space between function name and '('
  tty: serial: jsm: add blank line after declarations
  tty: serial: jsm: change the type of local variable
  tty: serial: imx: remove dead code imx_dma_rxint
  tty: serial: imx: disable ageing timer interrupt if dma in use
  serial: 8250: fix potential deadlock in rs485-mode
  serial: m32r_sio: Drop redundant .data assignment
  ...

tty: add SPDX identifiers to all remaining files in drivers/tty/

2017-11-08T12:08:12+00:00

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/tty files files with the correct SPDX license
identifier based on the license text in the file itself.  The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Jiri Slaby 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Chris Metcalf 
Cc: Jiri Kosina 
Cc: David Sterba 
Cc: James Hogan 
Cc: Rob Herring 
Cc: Eric Anholt 
Cc: Stefan Wahren 
Cc: Florian Fainelli 
Cc: Ray Jui 
Cc: Scott Branden 
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Joachim Eastwood 
Cc: Matthias Brugger 
Cc: Masahiro Yamada 
Cc: Tobias Klauser 
Cc: Russell King 
Cc: Vineet Gupta 
Cc: Richard Genoud 
Cc: Alexander Shiyan 
Cc: Baruch Siach 
Cc: "Maciej W. Rozycki" 
Cc: "Uwe Kleine-König" 
Cc: Pat Gefre 
Cc: "Guilherme G. Piccoli" 
Cc: Jason Wessel 
Cc: Vladimir Zapolskiy 
Cc: Sylvain Lemieux 
Cc: Carlo Caione 
Cc: Kevin Hilman 
Cc: Liviu Dudau 
Cc: Sudeep Holla 
Cc: Lorenzo Pieralisi 
Cc: Andy Gross 
Cc: David Brown 
Cc: "Andreas Färber" 
Cc: Kevin Cernekee 
Cc: Laxman Dewangan 
Cc: Thierry Reding 
Cc: Jonathan Hunter 
Cc: Barry Song 
Cc: Patrice Chotard 
Cc: Maxime Coquelin 
Cc: Alexandre Torgue 
Cc: "David S. Miller" 
Cc: Peter Korsgaard 
Cc: Timur Tabi 
Cc: Tony Prisk 
Cc: Michal Simek 
Cc: "Sören Brinkmann" 
Cc: Thomas Gleixner 
Cc: Kate Stewart 
Cc: Philippe Ombredanne 
Cc: Jiri Slaby 
Signed-off-by: Greg Kroah-Hartman

tty: fall back to N_NULL if switching to N_TTY fails during hangup

2017-10-13T23:18:33+00:00

We have seen NULL-pointer dereference crashes in tty->disc_data when the
N_TTY fallback driver failed to open during hangup.  The immediate cause
of this open to fail has been addressed in the preceding patch to
vmalloc(), but this code could be more robust.

As Alan pointed out in commit 8a8dabf2dd68 ("tty: handle the case where
we cannot restore a line discipline"), the N_TTY driver, historically
the safe fallback that could never fail, can indeed fail, but the
surrounding code is not prepared to handle this.  To avoid crashes he
added a new N_NULL driver to take N_TTY's place as the last resort.

Hook that fallback up to the hangup path.  Update tty_ldisc_reinit() to
reflect the reality that n_tty_open can indeed fail.

Link: http://lkml.kernel.org/r/20171004185959.GC2136@cmpxchg.org
Signed-off-by: Johannes Weiner 
Cc: Alan Cox 
Cc: Christoph Hellwig 
Cc: Dmitry Vyukov 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'tty-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2017-07-04T03:04:16+00:00

Pull tty/serial updates from Greg KH:
 "Here is the large tty/serial patchset for 4.13-rc1.

  A lot of tty and serial driver updates are in here, along with some
  fixups for some __get/put_user usages that were reported. Nothing
  huge, just lots of development by a number of different developers,
  full details in the shortlog.

  All of these have been in linux-next for a while"

* tag 'tty-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (71 commits)
  tty: serial: lpuart: add a more accurate baud rate calculation method
  tty: serial: lpuart: add earlycon support for imx7ulp
  tty: serial: lpuart: add imx7ulp support
  dt-bindings: serial: fsl-lpuart: add i.MX7ULP support
  tty: serial: lpuart: add little endian 32 bit register support
  tty: serial: lpuart: refactor lpuart32_{read|write} prototype
  tty: serial: lpuart: introduce lpuart_soc_data to represent SoC property
  serial: imx-serial - move DMA buffer configuration to DT
  serial: imx: Enable RTSD only when needed
  serial: imx: Remove unused members from imx_port struct
  serial: 8250: 8250_omap: Fix race b/w dma completion and RX timeout
  serial: 8250: Fix THRE flag usage for CAP_MINI
  tty/serial: meson_uart: update to stable bindings
  dt-bindings: serial: Add bindings for the Amlogic Meson UARTs
  serial: Delete dead code for CIR serial ports
  serial: sirf: make of_device_ids const
  serial/mpsc: switch to dma_alloc_attrs
  tty: serial: Add Actions Semi Owl UART earlycon
  dt-bindings: serial: Document Actions Semi Owl UARTs
  tty/serial: atmel: make the driver DT only
  ...

tty: handle the case where we cannot restore a line discipline

2017-06-03T09:43:46+00:00

Historically the N_TTY driver could never fail but this has become broken over
time. Rather than trying to rewrite half the ldisc layer to fix the breakage
introduce a second level of fallback with an N_NULL ldisc which cannot fail,
and thus restore the guarantees required by the ldisc layer.

We still try and fail to N_TTY first. It's much more useful to find yourself
back in your old ldisc (first attempt) or in N_TTY (second attempt), and while
I'm not aware of any code out there that makes those assumptions it's good to
drive(r) defensively.

Signed-off-by: Alan Cox 
Reported-by: Dmitry Vyukov 
Tested-by: Dmitry Vyukov 
Signed-off-by: Greg Kroah-Hartman

staging: speakup: add tty-based comms functions

2017-05-16T12:05:42+00:00

This adds spk_ttyio.c file. It contains a set of functions which implement
those methods in spk_synth struct which relate to sending bytes out using
serial comms. Implementations in this file perform the same function but
using TTY subsystem instead. Currently synths access serial ports, directly
poking standard ISA ports by trying to steal them from serial driver. Some ISA
cards actually need this way of doing it, but most other synthesizers don't,
and can actually work by using the proper TTY subsystem through a new N_SPEAKUP
line discipline. So this adds the methods for drivers to switch to accessing
serial ports through the TTY subsystem, whenever appropriate.

Signed-off-by: Okash Khawaja 
Reviewed-by: Samuel Thibault 
Signed-off-by: Greg Kroah-Hartman

Revert "tty: don't panic on OOM in tty_set_ldisc()"

2017-04-14T08:59:56+00:00

This reverts commit 5362544bebe85071188dd9e479b5a5040841c895 as it is
reported to cause a reproducable crash.

Fixes: 5362544bebe8 ("tty: don't panic on OOM in tty_set_ldisc()")
Reported-by: Vegard Nossum 
Cc: Dmitry Vyukov 
Cc: 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Peter Hurley 
Cc: One Thousand Gnomes 
Cc: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

tty: fix data race in tty_ldisc_ref_wait()

2017-03-17T05:07:10+00:00

tty_ldisc_ref_wait() checks tty->ldisc under tty->ldisc_sem.
But if ldisc==NULL it releases them sem and reloads
tty->ldisc without holding the sem. This is wrong and
can lead to returning non-NULL ldisc without protection.

Don't reload tty->ldisc second time.

Signed-off-by: Dmitry Vyukov 
Cc: syzkaller@googlegroups.com
Cc: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Peter Hurley 
Cc: One Thousand Gnomes 
Signed-off-by: Greg Kroah-Hartman

tty: don't panic on OOM in tty_set_ldisc()

2017-03-17T05:07:10+00:00

If tty_ldisc_open() fails in tty_set_ldisc(), it tries to go back
to the old discipline or N_TTY. But that can fail as well, in such
case it panics. This is not a graceful way to handle OOM.

Leave ldisc==NULL if all attempts fail instead.
Also use existing tty_ldisc_reinit() helper function instead of
tty_ldisc_restore(). Also don't WARN/BUG in tty_ldisc_reinit()
if N_TTY fails, which would have the same net effect of bringing
kernel down on OOM. Instead print a single line message about
what has happened.

Signed-off-by: Dmitry Vyukov 
Cc: syzkaller@googlegroups.com
Cc: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Peter Hurley 
Cc: One Thousand Gnomes 
Signed-off-by: Greg Kroah-Hartman

tty: Eliminate global symbol tty_ldisc_N_TTY

2016-01-27T23:13:28+00:00

Reduce global tty symbols; move and rename tty_ldisc_begin() as
n_tty_init() and redefine the N_TTY ldisc ops as file scope.

Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman