Commit Graph

265 Commits

Author SHA1 Message Date
Greg Kroah-Hartman 27cfb3a53b tty: Handle problem if line discipline does not have receive_buf
Some tty line disciplines do not have a receive buf callback, so
properly check for that before calling it.  If they do not have this
callback, just eat the character quietly, as we can't fail this call.

Reported-by: Jann Horn <jannh@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-21 17:41:02 +01:00
Dmitry Safonov d3736d82e8 tty: Don't hold ldisc lock in tty_reopen() if ldisc present
Try to get reference for ldisc during tty_reopen().
If ldisc present, we don't need to do tty_ldisc_reinit() and lock the
write side for line discipline semaphore.
Effectively, it optimizes fast-path for tty_reopen(), but more
importantly it won't interrupt ongoing IO on the tty as no ldisc change
is needed.
Fixes user-visible issue when tty_reopen() interrupted login process for
user with a long password, observed and reported by Lukas.

Fixes: c96cf923a9 ("tty: Don't block on IO when ldisc change is pending")
Fixes: 83d817f410 ("tty: Hold tty_ldisc_lock() during tty_reopen()")
Cc: Jiri Slaby <jslaby@suse.com>
Reported-by: Lukas F. Hartmann <lukas@mntmn.com>
Tested-by: Lukas F. Hartmann <lukas@mntmn.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-11 17:03:42 +01:00
Greg Kroah-Hartman 9c96f401e9 Merge 4.20-rc6 into tty-next
We want the TTY changes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-10 10:17:45 +01:00
Dmitry Safonov cf62a1a137 tty: Simplify tty->count math in tty_reopen()
As notted by Jiri, tty_ldisc_reinit() shouldn't rely on tty counter.
Simplify math by increasing the counter after reinit success.

Cc: Jiri Slaby <jslaby@suse.com>
Link: lkml.kernel.org/r/<20180829022353.23568-2-dima@arista.com>
Suggested-by: Jiri Slaby <jslaby@suse.com>
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-05 12:16:33 +01:00
Dmitry Safonov 83d817f410 tty: Hold tty_ldisc_lock() during tty_reopen()
tty_ldisc_reinit() doesn't race with neither tty_ldisc_hangup()
nor set_ldisc() nor tty_ldisc_release() as they use tty lock.
But it races with anyone who expects line discipline to be the same
after hoding read semaphore in tty_ldisc_ref().

We've seen the following crash on v4.9.108 stable:

BUG: unable to handle kernel paging request at 0000000000002260
IP: [..] n_tty_receive_buf_common+0x5f/0x86d
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 [..] n_tty_receive_buf2
 [..] tty_ldisc_receive_buf
 [..] flush_to_ldisc
 [..] process_one_work
 [..] worker_thread
 [..] kthread
 [..] ret_from_fork

tty_ldisc_reinit() should be called with ldisc_sem hold for writing,
which will protect any reader against line discipline changes.

Cc: Jiri Slaby <jslaby@suse.com>
Cc: stable@vger.kernel.org # b027e2298b ("tty: fix data race between tty_init_dev and flush of buf")
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: syzbot+3aa9784721dfb90e984d@syzkaller.appspotmail.com
Tested-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Tested-by: Tycho Andersen <tycho@tycho.ws>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-05 12:16:33 +01:00
Johan Hovold f51ccf4621 USB: serial: console: fix reported terminal settings
The USB-serial console implementation has never reported the actual
terminal settings used. Despite storing the corresponding cflags in its
struct console, these were never honoured on later tty open() where the
tty termios would be left initialised to the driver defaults.

Unlike the serial console implementation, the USB-serial code calls
subdriver open() already at console setup. While calling set_termios()
and write() before open() looks like it could work for some USB-serial
drivers, others definitely do not expect this, so modelling this after
serial core is going to be intrusive, if at all possible.

Instead, use a (renamed) tty helper to save the termios data used at
console setup so that the tty termios reflects the actual terminal
settings after a subsequent tty open().

Note that the calls to tty_init_termios() (tty_driver_install()) and
tty_save_termios() are serialised using the disconnect mutex.

This specifically fixes a regression that was triggered by a recent
change adding software flow control to the pl2303 driver: a getty trying
to disable flow control while leaving the baud rate unchanged would now
also set the baud rate to the driver default (prior to the flow-control
change this had been a noop).

Fixes: 7041d9c3f0 ("USB: serial: pl2303: add support for tx xon/xoff flow control")
Cc: stable <stable@vger.kernel.org>	# 4.18
Cc: Florian Zumbiehl <florz@florz.de>
Reported-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
2018-12-05 11:29:10 +01:00
Linus Torvalds 5bd4af34a0 TTY/Serial patches for 4.20-rc1
Here is the big tty and serial pull request for 4.20-rc1
 
 Lots of little things here, including a merge from the SPI tree in order
 to keep things simpler for everyone to sync around for one platform.
 
 Major stuff is:
 	- tty buffer clearing after use
 	- atmel_serial fixes and additions
 	- xilinx uart driver updates
 and of course, lots of tiny fixes and additions to individual serial
 drivers.
 
 All of these have been in linux-next with no reported issues for a
 while.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial updates from Greg KH:
 "Here is the big tty and serial pull request for 4.20-rc1

  Lots of little things here, including a merge from the SPI tree in
  order to keep things simpler for everyone to sync around for one
  platform.

  Major stuff is:

   - tty buffer clearing after use

   - atmel_serial fixes and additions

   - xilinx uart driver updates

  and of course, lots of tiny fixes and additions to individual serial
  drivers.

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

* tag 'tty-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (66 commits)
  of: base: Change logic in of_alias_get_alias_list()
  of: base: Fix english spelling in of_alias_get_alias_list()
  serial: sh-sci: do not warn if DMA transfers are not supported
  serial: uartps: Do not allow use aliases >= MAX_UART_INSTANCES
  tty: check name length in tty_find_polling_driver()
  serial: sh-sci: Add r8a77990 support
  tty: wipe buffer if not echoing data
  tty: wipe buffer.
  serial: fsl_lpuart: Remove the alias node dependence
  TTY: sn_console: Replace spin_is_locked() with spin_trylock()
  Revert "serial:serial_core: Allow use of CTS for PPS line discipline"
  serial: 8250_uniphier: add auto-flow-control support
  serial: 8250_uniphier: flatten probe function
  serial: 8250_uniphier: remove unused "fifo-size" property
  dt-bindings: serial: sh-sci: Document r8a7744 bindings
  serial: uartps: Fix missing unlock on error in cdns_get_id()
  tty/serial: atmel: add ISO7816 support
  tty/serial_core: add ISO7816 infrastructure
  serial:serial_core: Allow use of CTS for PPS line discipline
  serial: docs: Fix filename for serial reference implementation
  ...
2018-10-29 10:42:20 -07:00
Linus Torvalds 44adbac8f7 Merge branch 'work.tty-ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull tty ioctl updates from Al Viro:
 "This is the compat_ioctl work related to tty ioctls.

  Quite a bit of dead code taken out, all tty-related stuff gone from
  fs/compat_ioctl.c. A bunch of compat bugs fixed - some still remain,
  but all more or less generic tty-related ioctls should be covered
  (remaining issues are in things like driver-private ioctls in a pcmcia
  serial card driver not getting properly handled in 32bit processes on
  64bit host, etc)"

* 'work.tty-ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (53 commits)
  kill TIOCSERGSTRUCT
  change semantics of ldisc ->compat_ioctl()
  kill TIOCSER[SG]WILD
  synclink_gt(): fix compat_ioctl()
  pty: fix compat ioctls
  compat_ioctl - kill keyboard ioctl handling
  gigaset: add ->compat_ioctl()
  vt_compat_ioctl(): clean up, use compat_ptr() properly
  gigaset: don't try to printk userland buffer contents
  dgnc: don't bother with (empty) stub for TCXONC
  dgnc: leave TIOC[GS]SOFTCAR to ldisc
  remove fallback to drivers for TIOCGICOUNT
  dgnc: break-related ioctls won't reach ->ioctl()
  kill the rest of tty COMPAT_IOCTL() entries
  dgnc: TIOCM... won't reach ->ioctl()
  isdn_tty: TCSBRK{,P} won't reach ->ioctl()
  kill capinc_tty_ioctl()
  take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()
  synclink: reduce pointless checks in ->ioctl()
  complete ->[sg]et_serial() switchover
  ...
2018-10-24 14:43:41 +01:00
Linus Torvalds ba9f6f8954 Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull siginfo updates from Eric Biederman:
 "I have been slowly sorting out siginfo and this is the culmination of
  that work.

  The primary result is in several ways the signal infrastructure has
  been made less error prone. The code has been updated so that manually
  specifying SEND_SIG_FORCED is never necessary. The conversion to the
  new siginfo sending functions is now complete, which makes it
  difficult to send a signal without filling in the proper siginfo
  fields.

  At the tail end of the patchset comes the optimization of decreasing
  the size of struct siginfo in the kernel from 128 bytes to about 48
  bytes on 64bit. The fundamental observation that enables this is by
  definition none of the known ways to use struct siginfo uses the extra
  bytes.

  This comes at the cost of a small user space observable difference.
  For the rare case of siginfo being injected into the kernel only what
  can be copied into kernel_siginfo is delivered to the destination, the
  rest of the bytes are set to 0. For cases where the signal and the
  si_code are known this is safe, because we know those bytes are not
  used. For cases where the signal and si_code combination is unknown
  the bits that won't fit into struct kernel_siginfo are tested to
  verify they are zero, and the send fails if they are not.

  I made an extensive search through userspace code and I could not find
  anything that would break because of the above change. If it turns out
  I did break something it will take just the revert of a single change
  to restore kernel_siginfo to the same size as userspace siginfo.

  Testing did reveal dependencies on preferring the signo passed to
  sigqueueinfo over si->signo, so bit the bullet and added the
  complexity necessary to handle that case.

  Testing also revealed bad things can happen if a negative signal
  number is passed into the system calls. Something no sane application
  will do but something a malicious program or a fuzzer might do. So I
  have fixed the code that performs the bounds checks to ensure negative
  signal numbers are handled"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits)
  signal: Guard against negative signal numbers in copy_siginfo_from_user32
  signal: Guard against negative signal numbers in copy_siginfo_from_user
  signal: In sigqueueinfo prefer sig not si_signo
  signal: Use a smaller struct siginfo in the kernel
  signal: Distinguish between kernel_siginfo and siginfo
  signal: Introduce copy_siginfo_from_user and use it's return value
  signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE
  signal: Fail sigqueueinfo if si_signo != sig
  signal/sparc: Move EMT_TAGOVF into the generic siginfo.h
  signal/unicore32: Use force_sig_fault where appropriate
  signal/unicore32: Generate siginfo in ucs32_notify_die
  signal/unicore32: Use send_sig_fault where appropriate
  signal/arc: Use force_sig_fault where appropriate
  signal/arc: Push siginfo generation into unhandled_exception
  signal/ia64: Use force_sig_fault where appropriate
  signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn
  signal/ia64: Use the generic force_sigsegv in setup_frame
  signal/arm/kvm: Use send_sig_mceerr
  signal/arm: Use send_sig_fault where appropriate
  signal/arm: Use force_sig_fault where appropriate
  ...
2018-10-24 11:22:39 +01:00
Al Viro f0193d3ea7 change semantics of ldisc ->compat_ioctl()
First of all, make it return int.  Returning long when native method
had never allowed that is ridiculous and inconvenient.

More importantly, change the caller; if ldisc ->compat_ioctl() is NULL
or returns -ENOIOCTLCMD, tty_compat_ioctl() will try to feed cmd and
compat_ptr(arg) to ldisc's native ->ioctl().

That simplifies ->compat_ioctl() instances quite a bit - they only
need to deal with ioctls that are neither generic tty ones (those
would get shunted off to tty_ioctl()) nor simple compat pointer ones.

Note that something like TCFLSH won't reach ->compat_ioctl(),
even if ldisc ->ioctl() does handle it - it will be recognized
earlier and passed to tty_ioctl() (and ultimately - ldisc ->ioctl()).

For many ldiscs it means that NULL ->compat_ioctl() does the
right thing.  Those where it won't serve (see e.g. n_r3964.c) are
also easily dealt with - we need to handle the numeric-argument
ioctls (calling the native instance) and, if such would exist,
the ioctls that need layout conversion, etc.

All in-tree ldiscs dealt with.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-10-13 00:50:53 -04:00
Al Viro a309619922 remove fallback to drivers for TIOCGICOUNT
none of them handles it anyway.

Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-10-13 00:50:47 -04:00
Al Viro 7765435030 take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-10-13 00:50:44 -04:00
Al Viro 930236a308 complete ->[sg]et_serial() switchover
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-10-13 00:50:43 -04:00
Miles Chen 33a1a7be19 tty: check name length in tty_find_polling_driver()
The issue is found by a fuzzing test.
If tty_find_polling_driver() recevies an incorrect input such as
',,' or '0b', the len becomes 0 and strncmp() always return 0.
In this case, a null p->ops->poll_init() is called and it causes a kernel
panic.

Fix this by checking name length against zero in tty_find_polling_driver().

$echo ,, > /sys/module/kgdboc/parameters/kgdboc
[   20.804451] WARNING: CPU: 1 PID: 104 at drivers/tty/serial/serial_core.c:457
uart_get_baud_rate+0xe8/0x190
[   20.804917] Modules linked in:
[   20.805317] CPU: 1 PID: 104 Comm: sh Not tainted 4.19.0-rc7ajb #8
[   20.805469] Hardware name: linux,dummy-virt (DT)
[   20.805732] pstate: 20000005 (nzCv daif -PAN -UAO)
[   20.805895] pc : uart_get_baud_rate+0xe8/0x190
[   20.806042] lr : uart_get_baud_rate+0xc0/0x190
[   20.806476] sp : ffffffc06acff940
[   20.806676] x29: ffffffc06acff940 x28: 0000000000002580
[   20.806977] x27: 0000000000009600 x26: 0000000000009600
[   20.807231] x25: ffffffc06acffad0 x24: 00000000ffffeff0
[   20.807576] x23: 0000000000000001 x22: 0000000000000000
[   20.807807] x21: 0000000000000001 x20: 0000000000000000
[   20.808049] x19: ffffffc06acffac8 x18: 0000000000000000
[   20.808277] x17: 0000000000000000 x16: 0000000000000000
[   20.808520] x15: ffffffffffffffff x14: ffffffff00000000
[   20.808757] x13: ffffffffffffffff x12: 0000000000000001
[   20.809011] x11: 0101010101010101 x10: ffffff880d59ff5f
[   20.809292] x9 : ffffff880d59ff5e x8 : ffffffc06acffaf3
[   20.809549] x7 : 0000000000000000 x6 : ffffff880d59ff5f
[   20.809803] x5 : 0000000080008001 x4 : 0000000000000003
[   20.810056] x3 : ffffff900853e6b4 x2 : dfffff9000000000
[   20.810693] x1 : ffffffc06acffad0 x0 : 0000000000000cb0
[   20.811005] Call trace:
[   20.811214]  uart_get_baud_rate+0xe8/0x190
[   20.811479]  serial8250_do_set_termios+0xe0/0x6f4
[   20.811719]  serial8250_set_termios+0x48/0x54
[   20.811928]  uart_set_options+0x138/0x1bc
[   20.812129]  uart_poll_init+0x114/0x16c
[   20.812330]  tty_find_polling_driver+0x158/0x200
[   20.812545]  configure_kgdboc+0xbc/0x1bc
[   20.812745]  param_set_kgdboc_var+0xb8/0x150
[   20.812960]  param_attr_store+0xbc/0x150
[   20.813160]  module_attr_store+0x40/0x58
[   20.813364]  sysfs_kf_write+0x8c/0xa8
[   20.813563]  kernfs_fop_write+0x154/0x290
[   20.813764]  vfs_write+0xf0/0x278
[   20.813951]  __arm64_sys_write+0x84/0xf4
[   20.814400]  el0_svc_common+0xf4/0x1dc
[   20.814616]  el0_svc_handler+0x98/0xbc
[   20.814804]  el0_svc+0x8/0xc
[   20.822005] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[   20.826913] Mem abort info:
[   20.827103]   ESR = 0x84000006
[   20.827352]   Exception class = IABT (current EL), IL = 16 bits
[   20.827655]   SET = 0, FnV = 0
[   20.827855]   EA = 0, S1PTW = 0
[   20.828135] user pgtable: 4k pages, 39-bit VAs, pgdp = (____ptrval____)
[   20.828484] [0000000000000000] pgd=00000000aadee003, pud=00000000aadee003, pmd=0000000000000000
[   20.829195] Internal error: Oops: 84000006 [#1] SMP
[   20.829564] Modules linked in:
[   20.829890] CPU: 1 PID: 104 Comm: sh Tainted: G        W         4.19.0-rc7ajb #8
[   20.830545] Hardware name: linux,dummy-virt (DT)
[   20.830829] pstate: 60000085 (nZCv daIf -PAN -UAO)
[   20.831174] pc :           (null)
[   20.831457] lr : serial8250_do_set_termios+0x358/0x6f4
[   20.831727] sp : ffffffc06acff9b0
[   20.831936] x29: ffffffc06acff9b0 x28: ffffff9008d7c000
[   20.832267] x27: ffffff900969e16f x26: 0000000000000000
[   20.832589] x25: ffffff900969dfb0 x24: 0000000000000000
[   20.832906] x23: ffffffc06acffad0 x22: ffffff900969e160
[   20.833232] x21: 0000000000000000 x20: ffffffc06acffac8
[   20.833559] x19: ffffff900969df90 x18: 0000000000000000
[   20.833878] x17: 0000000000000000 x16: 0000000000000000
[   20.834491] x15: ffffffffffffffff x14: ffffffff00000000
[   20.834821] x13: ffffffffffffffff x12: 0000000000000001
[   20.835143] x11: 0101010101010101 x10: ffffff880d59ff5f
[   20.835467] x9 : ffffff880d59ff5e x8 : ffffffc06acffaf3
[   20.835790] x7 : 0000000000000000 x6 : ffffff880d59ff5f
[   20.836111] x5 : c06419717c314100 x4 : 0000000000000007
[   20.836419] x3 : 0000000000000000 x2 : 0000000000000000
[   20.836732] x1 : 0000000000000001 x0 : ffffff900969df90
[   20.837100] Process sh (pid: 104, stack limit = 0x(____ptrval____))
[   20.837396] Call trace:
[   20.837566]            (null)
[   20.837816]  serial8250_set_termios+0x48/0x54
[   20.838089]  uart_set_options+0x138/0x1bc
[   20.838570]  uart_poll_init+0x114/0x16c
[   20.838834]  tty_find_polling_driver+0x158/0x200
[   20.839119]  configure_kgdboc+0xbc/0x1bc
[   20.839380]  param_set_kgdboc_var+0xb8/0x150
[   20.839658]  param_attr_store+0xbc/0x150
[   20.839920]  module_attr_store+0x40/0x58
[   20.840183]  sysfs_kf_write+0x8c/0xa8
[   20.840183]  sysfs_kf_write+0x8c/0xa8
[   20.840440]  kernfs_fop_write+0x154/0x290
[   20.840702]  vfs_write+0xf0/0x278
[   20.840942]  __arm64_sys_write+0x84/0xf4
[   20.841209]  el0_svc_common+0xf4/0x1dc
[   20.841471]  el0_svc_handler+0x98/0xbc
[   20.841713]  el0_svc+0x8/0xc
[   20.842057] Code: bad PC value
[   20.842764] ---[ end trace a8835d7de79aaadf ]---
[   20.843134] Kernel panic - not syncing: Fatal exception
[   20.843515] SMP: stopping secondary CPUs
[   20.844289] Kernel Offset: disabled
[   20.844634] CPU features: 0x0,21806002
[   20.844857] Memory Limit: none
[   20.845172] ---[ end Kernel panic - not syncing: Fatal exception ]---

Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-11 19:59:29 +02:00
Dmitry Safonov fe32416790 tty: Drop tty->count on tty_reopen() failure
In case of tty_ldisc_reinit() failure, tty->count should be decremented
back, otherwise we will never release_tty().
Tetsuo reported that it fixes noisy warnings on tty release like:
  pts pts4033: tty_release: tty->count(10529) != (#fd's(7) + #kopen's(0))

Fixes: commit 892d1fa7ea ("tty: Destroy ldisc instance on hangup")

Cc: stable@vger.kernel.org # v4.6+
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Tested-by: Jiri Slaby <jslaby@suse.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-18 15:42:24 +02:00
Eric W. Biederman a8ebd17160 tty_io: Use group_send_sig_info in __do_SACK to note it is a session being killed
Replace send_sig and force_sig in __do_SAK with group_send_sig_info
the general helper for sending a signal to a process group.  This is
wordier but it allows specifying PIDTYPE_SID so that the signal code
knows the signal went to a session.

Both force_sig() and send_sig(..., 1) specify SEND_SIG_PRIV and the
new call of group_send_sig_info does that explicitly.  This is enough
to ensure even a pid namespace init is killed.

The global init remains unkillable.  The guarantee that __do_SAK tries
to provide is a clean path to login to a machine.  As the global init is
unkillable, if it chooses to hold open a tty it can violate this
guarantee.  A technique other than killing processes would be needed
to provide this guarantee to userspace.

The only difference between force_sig and send_sig when sending
SIGKILL is that SIGNAL_UNKILLABLE is cleared.  This has no affect on
the processing of a signal sent with SEND_SIG_PRIV by any process, making
it unnecessary, and not behavior that needs to be preserved.

force_sig was used originally because it did not take as many locks as
send_sig.  Today send_sig, force_sig and group_send_sig_info take the
same locks when delivering a signal.

group_send_sig_info also contains a permission check that force_sig
and send_sig do not.  However the presence of SEND_SIG_PRIV makes the
permission check a noop.  So the permission check does not result
in any behavioral differences.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-09-16 16:06:21 +02:00
Al Viro 2f46a2c1d4 tty_ioctl(): start taking TIOC[SG]SERIAL into separate methods
->set_serial() and ->get_serial() resp., both taking tty and
a kernel pointer to serial_struct.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-09-14 11:19:30 -04:00
Al Viro a913bc76ed tty_ioctl(): drop FIONBIO handling
That code had been live for 11 weeks back in 1992, but it had been 26 years
since sys_ioctl() began handling FIONBIO on its own.  Time to to bury the body,
already...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-09-14 11:12:36 -04:00
Al Viro e21120383f move compat handling of tty ioctls to tty_compat_ioctl()
ioctls that are
	* callable only via tty_ioctl()
	* not driver-specific
	* not demand data structure conversions
	* either always need passing arg as is or always demand compat_ptr()
get intercepted in tty_compat_ioctl() from the very beginning and
redirecter to tty_ioctl().  As the result, their entries in fs/compat_ioctl.c
(some of those had been missing, BTW) got removed, as well as
n_tty_compat_ioctl_helper() (now it's never called with any cmd it would accept).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-09-14 11:12:17 -04:00
Linus Torvalds 0214f46b3a Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull core signal handling updates from Eric Biederman:
 "It was observed that a periodic timer in combination with a
  sufficiently expensive fork could prevent fork from every completing.
  This contains the changes to remove the need for that restart.

  This set of changes is split into several parts:

   - The first part makes PIDTYPE_TGID a proper pid type instead
     something only for very special cases. The part starts using
     PIDTYPE_TGID enough so that in __send_signal where signals are
     actually delivered we know if the signal is being sent to a a group
     of processes or just a single process.

   - With that prep work out of the way the logic in fork is modified so
     that fork logically makes signals received while it is running
     appear to be received after the fork completes"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (22 commits)
  signal: Don't send signals to tasks that don't exist
  signal: Don't restart fork when signals come in.
  fork: Have new threads join on-going signal group stops
  fork: Skip setting TIF_SIGPENDING in ptrace_init_task
  signal: Add calculate_sigpending()
  fork: Unconditionally exit if a fatal signal is pending
  fork: Move and describe why the code examines PIDNS_ADDING
  signal: Push pid type down into complete_signal.
  signal: Push pid type down into __send_signal
  signal: Push pid type down into send_signal
  signal: Pass pid type into do_send_sig_info
  signal: Pass pid type into send_sigio_to_task & send_sigurg_to_task
  signal: Pass pid type into group_send_sig_info
  signal: Pass pid and pid type into send_sigqueue
  posix-timers: Noralize good_sigevent
  signal: Use PIDTYPE_TGID to clearly store where file signals will be sent
  pid: Implement PIDTYPE_TGID
  pids: Move the pgrp and session pid pointers from task_struct to signal_struct
  kvm: Don't open code task_pid in kvm_vcpu_ioctl
  pids: Compute task_tgid using signal->leader_pid
  ...
2018-08-21 13:47:29 -07:00
Eric W. Biederman 019191342f signal: Use PIDTYPE_TGID to clearly store where file signals will be sent
When f_setown is called a pid and a pid type are stored.  Replace the use
of PIDTYPE_PID with PIDTYPE_TGID as PIDTYPE_TGID goes to the entire thread
group.  Replace the use of PIDTYPE_MAX with PIDTYPE_PID as PIDTYPE_PID now
is only for a thread.

Update the users of __f_setown to use PIDTYPE_TGID instead of
PIDTYPE_PID.

For now the code continues to capture task_pid (when task_tgid would
really be appropriate), and iterate on PIDTYPE_PID (even when type ==
PIDTYPE_TGID) out of an abundance of caution to preserve existing
behavior.

Oleg Nesterov suggested using the test to ensure we use PIDTYPE_PID
for tgid lookup also be used to avoid taking the tasklist lock.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-07-21 10:43:12 -05:00
Arnd Bergmann c884f871fb tty: use 64-bit timstamp
The automated VFS conversion to timespec64 has left one caller of
the deprecated get_seconds() function in the tty driver, this cleans
it up to call ktime_get_real_seconds() instead, fixing the possible
overflow.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-28 21:07:54 +09:00
Deepa Dinamani 95582b0083 vfs: change inode times to use struct timespec64
struct timespec is not y2038 safe. Transition vfs to use
y2038 safe struct timespec64 instead.

The change was made with the help of the following cocinelle
script. This catches about 80% of the changes.
All the header file and logic changes are included in the
first 5 rules. The rest are trivial substitutions.
I avoid changing any of the function signatures or any other
filesystem specific data structures to keep the patch simple
for review.

The script can be a little shorter by combining different cases.
But, this version was sufficient for my usecase.

virtual patch

@ depends on patch @
identifier now;
@@
- struct timespec
+ struct timespec64
  current_time ( ... )
  {
- struct timespec now = current_kernel_time();
+ struct timespec64 now = current_kernel_time64();
  ...
- return timespec_trunc(
+ return timespec64_trunc(
  ... );
  }

@ depends on patch @
identifier xtime;
@@
 struct \( iattr \| inode \| kstat \) {
 ...
-       struct timespec xtime;
+       struct timespec64 xtime;
 ...
 }

@ depends on patch @
identifier t;
@@
 struct inode_operations {
 ...
int (*update_time) (...,
-       struct timespec t,
+       struct timespec64 t,
...);
 ...
 }

@ depends on patch @
identifier t;
identifier fn_update_time =~ "update_time$";
@@
 fn_update_time (...,
- struct timespec *t,
+ struct timespec64 *t,
 ...) { ... }

@ depends on patch @
identifier t;
@@
lease_get_mtime( ... ,
- struct timespec *t
+ struct timespec64 *t
  ) { ... }

@te depends on patch forall@
identifier ts;
local idexpression struct inode *inode_node;
identifier i_xtime =~ "^i_[acm]time$";
identifier ia_xtime =~ "^ia_[acm]time$";
identifier fn_update_time =~ "update_time$";
identifier fn;
expression e, E3;
local idexpression struct inode *node1;
local idexpression struct inode *node2;
local idexpression struct iattr *attr1;
local idexpression struct iattr *attr2;
local idexpression struct iattr attr;
identifier i_xtime1 =~ "^i_[acm]time$";
identifier i_xtime2 =~ "^i_[acm]time$";
identifier ia_xtime1 =~ "^ia_[acm]time$";
identifier ia_xtime2 =~ "^ia_[acm]time$";
@@
(
(
- struct timespec ts;
+ struct timespec64 ts;
|
- struct timespec ts = current_time(inode_node);
+ struct timespec64 ts = current_time(inode_node);
)

<+... when != ts
(
- timespec_equal(&inode_node->i_xtime, &ts)
+ timespec64_equal(&inode_node->i_xtime, &ts)
|
- timespec_equal(&ts, &inode_node->i_xtime)
+ timespec64_equal(&ts, &inode_node->i_xtime)
|
- timespec_compare(&inode_node->i_xtime, &ts)
+ timespec64_compare(&inode_node->i_xtime, &ts)
|
- timespec_compare(&ts, &inode_node->i_xtime)
+ timespec64_compare(&ts, &inode_node->i_xtime)
|
ts = current_time(e)
|
fn_update_time(..., &ts,...)
|
inode_node->i_xtime = ts
|
node1->i_xtime = ts
|
ts = inode_node->i_xtime
|
<+... attr1->ia_xtime ...+> = ts
|
ts = attr1->ia_xtime
|
ts.tv_sec
|
ts.tv_nsec
|
btrfs_set_stack_timespec_sec(..., ts.tv_sec)
|
btrfs_set_stack_timespec_nsec(..., ts.tv_nsec)
|
- ts = timespec64_to_timespec(
+ ts =
...
-)
|
- ts = ktime_to_timespec(
+ ts = ktime_to_timespec64(
...)
|
- ts = E3
+ ts = timespec_to_timespec64(E3)
|
- ktime_get_real_ts(&ts)
+ ktime_get_real_ts64(&ts)
|
fn(...,
- ts
+ timespec64_to_timespec(ts)
,...)
)
...+>
(
<... when != ts
- return ts;
+ return timespec64_to_timespec(ts);
...>
)
|
- timespec_equal(&node1->i_xtime1, &node2->i_xtime2)
+ timespec64_equal(&node1->i_xtime2, &node2->i_xtime2)
|
- timespec_equal(&node1->i_xtime1, &attr2->ia_xtime2)
+ timespec64_equal(&node1->i_xtime2, &attr2->ia_xtime2)
|
- timespec_compare(&node1->i_xtime1, &node2->i_xtime2)
+ timespec64_compare(&node1->i_xtime1, &node2->i_xtime2)
|
node1->i_xtime1 =
- timespec_trunc(attr1->ia_xtime1,
+ timespec64_trunc(attr1->ia_xtime1,
...)
|
- attr1->ia_xtime1 = timespec_trunc(attr2->ia_xtime2,
+ attr1->ia_xtime1 =  timespec64_trunc(attr2->ia_xtime2,
...)
|
- ktime_get_real_ts(&attr1->ia_xtime1)
+ ktime_get_real_ts64(&attr1->ia_xtime1)
|
- ktime_get_real_ts(&attr.ia_xtime1)
+ ktime_get_real_ts64(&attr.ia_xtime1)
)

@ depends on patch @
struct inode *node;
struct iattr *attr;
identifier fn;
identifier i_xtime =~ "^i_[acm]time$";
identifier ia_xtime =~ "^ia_[acm]time$";
expression e;
@@
(
- fn(node->i_xtime);
+ fn(timespec64_to_timespec(node->i_xtime));
|
 fn(...,
- node->i_xtime);
+ timespec64_to_timespec(node->i_xtime));
|
- e = fn(attr->ia_xtime);
+ e = fn(timespec64_to_timespec(attr->ia_xtime));
)

@ depends on patch forall @
struct inode *node;
struct iattr *attr;
identifier i_xtime =~ "^i_[acm]time$";
identifier ia_xtime =~ "^ia_[acm]time$";
identifier fn;
@@
{
+ struct timespec ts;
<+...
(
+ ts = timespec64_to_timespec(node->i_xtime);
fn (...,
- &node->i_xtime,
+ &ts,
...);
|
+ ts = timespec64_to_timespec(attr->ia_xtime);
fn (...,
- &attr->ia_xtime,
+ &ts,
...);
)
...+>
}

@ depends on patch forall @
struct inode *node;
struct iattr *attr;
struct kstat *stat;
identifier ia_xtime =~ "^ia_[acm]time$";
identifier i_xtime =~ "^i_[acm]time$";
identifier xtime =~ "^[acm]time$";
identifier fn, ret;
@@
{
+ struct timespec ts;
<+...
(
+ ts = timespec64_to_timespec(node->i_xtime);
ret = fn (...,
- &node->i_xtime,
+ &ts,
...);
|
+ ts = timespec64_to_timespec(node->i_xtime);
ret = fn (...,
- &node->i_xtime);
+ &ts);
|
+ ts = timespec64_to_timespec(attr->ia_xtime);
ret = fn (...,
- &attr->ia_xtime,
+ &ts,
...);
|
+ ts = timespec64_to_timespec(attr->ia_xtime);
ret = fn (...,
- &attr->ia_xtime);
+ &ts);
|
+ ts = timespec64_to_timespec(stat->xtime);
ret = fn (...,
- &stat->xtime);
+ &ts);
)
...+>
}

@ depends on patch @
struct inode *node;
struct inode *node2;
identifier i_xtime1 =~ "^i_[acm]time$";
identifier i_xtime2 =~ "^i_[acm]time$";
identifier i_xtime3 =~ "^i_[acm]time$";
struct iattr *attrp;
struct iattr *attrp2;
struct iattr attr ;
identifier ia_xtime1 =~ "^ia_[acm]time$";
identifier ia_xtime2 =~ "^ia_[acm]time$";
struct kstat *stat;
struct kstat stat1;
struct timespec64 ts;
identifier xtime =~ "^[acmb]time$";
expression e;
@@
(
( node->i_xtime2 \| attrp->ia_xtime2 \| attr.ia_xtime2 \) = node->i_xtime1  ;
|
 node->i_xtime2 = \( node2->i_xtime1 \| timespec64_trunc(...) \);
|
 node->i_xtime2 = node->i_xtime1 = node->i_xtime3 = \(ts \| current_time(...) \);
|
 node->i_xtime1 = node->i_xtime3 = \(ts \| current_time(...) \);
|
 stat->xtime = node2->i_xtime1;
|
 stat1.xtime = node2->i_xtime1;
|
( node->i_xtime2 \| attrp->ia_xtime2 \) = attrp->ia_xtime1  ;
|
( attrp->ia_xtime1 \| attr.ia_xtime1 \) = attrp2->ia_xtime2;
|
- e = node->i_xtime1;
+ e = timespec64_to_timespec( node->i_xtime1 );
|
- e = attrp->ia_xtime1;
+ e = timespec64_to_timespec( attrp->ia_xtime1 );
|
node->i_xtime1 = current_time(...);
|
 node->i_xtime2 = node->i_xtime1 = node->i_xtime3 =
- e;
+ timespec_to_timespec64(e);
|
 node->i_xtime1 = node->i_xtime3 =
- e;
+ timespec_to_timespec64(e);
|
- node->i_xtime1 = e;
+ node->i_xtime1 = timespec_to_timespec64(e);
)

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: <anton@tuxera.com>
Cc: <balbi@kernel.org>
Cc: <bfields@fieldses.org>
Cc: <darrick.wong@oracle.com>
Cc: <dhowells@redhat.com>
Cc: <dsterba@suse.com>
Cc: <dwmw2@infradead.org>
Cc: <hch@lst.de>
Cc: <hirofumi@mail.parknet.co.jp>
Cc: <hubcap@omnibond.com>
Cc: <jack@suse.com>
Cc: <jaegeuk@kernel.org>
Cc: <jaharkes@cs.cmu.edu>
Cc: <jslaby@suse.com>
Cc: <keescook@chromium.org>
Cc: <mark@fasheh.com>
Cc: <miklos@szeredi.hu>
Cc: <nico@linaro.org>
Cc: <reiserfs-devel@vger.kernel.org>
Cc: <richard@nod.at>
Cc: <sage@redhat.com>
Cc: <sfrench@samba.org>
Cc: <swhiteho@redhat.com>
Cc: <tj@kernel.org>
Cc: <trond.myklebust@primarydata.com>
Cc: <tytso@mit.edu>
Cc: <viro@zeniv.linux.org.uk>
2018-06-05 16:57:31 -07:00
Tetsuo Handa 903f9db10f tty: Don't call panic() at tty_ldisc_init()
syzbot is reporting kernel panic [1] triggered by memory allocation failure
at tty_ldisc_get() from tty_ldisc_init(). But since both tty_ldisc_get()
and caller of tty_ldisc_init() can cleanly handle errors, tty_ldisc_init()
does not need to call panic() when tty_ldisc_get() failed.

[1] https://syzkaller.appspot.com/bug?id=883431818e036ae6a9981156a64b821110f39187

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-23 11:05:52 +02:00
Tejun Heo 28b0f8a696 tty: make n_tty_read() always abort if hangup is in progress
A tty is hung up by __tty_hangup() setting file->f_op to
hung_up_tty_fops, which is skipped on ttys whose write operation isn't
tty_write().  This means that, for example, /dev/console whose write
op is redirected_tty_write() is never actually marked hung up.

Because n_tty_read() uses the hung up status to decide whether to
abort the waiting readers, the lack of hung-up marking can lead to the
following scenario.

 1. A session contains two processes.  The leader and its child.  The
    child ignores SIGHUP.

 2. The leader exits and starts disassociating from the controlling
    terminal (/dev/console).

 3. __tty_hangup() skips setting f_op to hung_up_tty_fops.

 4. SIGHUP is delivered and ignored.

 5. tty_ldisc_hangup() is invoked.  It wakes up the waits which should
    clear the read lockers of tty->ldisc_sem.

 6. The reader wakes up but because tty_hung_up_p() is false, it
    doesn't abort and goes back to sleep while read-holding
    tty->ldisc_sem.

 7. The leader progresses to tty_ldisc_lock() in tty_ldisc_hangup()
    and is now stuck in D sleep indefinitely waiting for
    tty->ldisc_sem.

The following is Alan's explanation on why some ttys aren't hung up.

 http://lkml.kernel.org/r/20171101170908.6ad08580@alans-desktop

 1. It broke the serial consoles because they would hang up and close
    down the hardware. With tty_port that *should* be fixable properly
    for any cases remaining.

 2. The console layer was (and still is) completely broken and doens't
    refcount properly. So if you turn on console hangups it breaks (as
    indeed does freeing consoles and half a dozen other things).

As neither can be fixed quickly, this patch works around the problem
by introducing a new flag, TTY_HUPPING, which is used solely to tell
n_tty_read() that hang-up is in progress for the console and the
readers should be aborted regardless of the hung-up status of the
device.

The following is a sample hung task warning caused by this issue.

  INFO: task agetty:2662 blocked for more than 120 seconds.
        Not tainted 4.11.3-dbg-tty-lockup-02478-gfd6c7ee-dirty #28
  "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
      0  2662      1 0x00000086
  Call Trace:
   __schedule+0x267/0x890
   schedule+0x36/0x80
   schedule_timeout+0x23c/0x2e0
   ldsem_down_write+0xce/0x1f6
   tty_ldisc_lock+0x16/0x30
   tty_ldisc_hangup+0xb3/0x1b0
   __tty_hangup+0x300/0x410
   disassociate_ctty+0x6c/0x290
   do_exit+0x7ef/0xb00
   do_group_exit+0x3f/0xa0
   get_signal+0x1b3/0x5d0
   do_signal+0x28/0x660
   exit_to_usermode_loop+0x46/0x86
   do_syscall_64+0x9c/0xb0
   entry_SYSCALL64_slow_path+0x25/0x25

The following is the repro.  Run "$PROG /dev/console".  The parent
process hangs in D state.

  #include <sys/types.h>
  #include <sys/stat.h>
  #include <sys/wait.h>
  #include <sys/ioctl.h>
  #include <fcntl.h>
  #include <unistd.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <errno.h>
  #include <signal.h>
  #include <time.h>
  #include <termios.h>

  int main(int argc, char **argv)
  {
	  struct sigaction sact = { .sa_handler = SIG_IGN };
	  struct timespec ts1s = { .tv_sec = 1 };
	  pid_t pid;
	  int fd;

	  if (argc < 2) {
		  fprintf(stderr, "test-hung-tty /dev/$TTY\n");
		  return 1;
	  }

	  /* fork a child to ensure that it isn't already the session leader */
	  pid = fork();
	  if (pid < 0) {
		  perror("fork");
		  return 1;
	  }

	  if (pid > 0) {
		  /* top parent, wait for everyone */
		  while (waitpid(-1, NULL, 0) >= 0)
			  ;
		  if (errno != ECHILD)
			  perror("waitpid");
		  return 0;
	  }

	  /* new session, start a new session and set the controlling tty */
	  if (setsid() < 0) {
		  perror("setsid");
		  return 1;
	  }

	  fd = open(argv[1], O_RDWR);
	  if (fd < 0) {
		  perror("open");
		  return 1;
	  }

	  if (ioctl(fd, TIOCSCTTY, 1) < 0) {
		  perror("ioctl");
		  return 1;
	  }

	  /* fork a child, sleep a bit and exit */
	  pid = fork();
	  if (pid < 0) {
		  perror("fork");
		  return 1;
	  }

	  if (pid > 0) {
		  nanosleep(&ts1s, NULL);
		  printf("Session leader exiting\n");
		  exit(0);
	  }

	  /*
	   * The child ignores SIGHUP and keeps reading from the controlling
	   * tty.  Because SIGHUP is ignored, the child doesn't get killed on
	   * parent exit and the bug in n_tty makes the read(2) block the
	   * parent's control terminal hangup attempt.  The parent ends up in
	   * D sleep until the child is explicitly killed.
	   */
	  sigaction(SIGHUP, &sact, NULL);
	  printf("Child reading tty\n");
	  while (1) {
		  char buf[1024];

		  if (read(fd, buf, sizeof(buf)) < 0) {
			  perror("read");
			  return 1;
		  }
	  }

	  return 0;
  }

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alan Cox <alan@llwyncelyn.cymru>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-28 13:21:10 +01:00
Linus Torvalds a9a08845e9 vfs: do bulk POLL* -> EPOLL* replacement
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-11 14:34:03 -08:00
Linus Torvalds db5933225f TTY/Staging driver updates for 4.16-rc1
Here is the big tty/serial driver update for 4.16-rc1.
 
 The usual number of various serial driver fixes and updates to try to
 get them to work with crazy hardware configurations (seriously, how many
 different ways are hardware engineers going to come up with to hook up a
 simple UART?)
 
 There is also some serdev bugfixes and updates, as well as a smattering
 of other small fixes in here.
 
 All have been in the linux-next tree for a while, with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/staging driver updates from Greg KH:
 "Here is the big tty/serial driver update for 4.16-rc1.

  The usual number of various serial driver fixes and updates to try to
  get them to work with crazy hardware configurations (seriously, how
  many different ways are hardware engineers going to come up with to
  hook up a simple UART?)

  There is also some serdev bugfixes and updates, as well as a
  smattering of other small fixes in here.

  All have been in the linux-next tree for a while, with no reported
  issues"

* tag 'tty-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (65 commits)
  tty: serial: exar: Relocate sleep wake-up handling
  tty: fix data race between tty_init_dev and flush of buf
  serial: imx: fix endless loop during suspend
  serial: core: mark port as initialized after successful IRQ change
  serdev: only match serdev devices
  serdev: do not generate modaliases for controllers
  serial: mxs-auart: don't use GPIOF_* with gpiod_get_direction
  serial: 8250_dw: Revert "Improve clock rate setting"
  MAINTAINERS: Add myself as designated reviewer for 8250_dw
  gpio: serial: max310x: Support open-drain configuration for GPIOs
  serdev: Fix serdev_uevent failure on ACPI enumerated serdev-controllers
  serial: 8250_ingenic: Parse earlycon options
  serial: 8250_ingenic: Add support for the JZ4770 SoC
  serial: core: Make uart_parse_options take const char* argument
  serial: 8250_of: fix return code when probe function fails to get reset
  serial: imx: Only wakeup via RTSDEN bit if the system has RTS/CTS
  serial: 8250_uniphier: fix error return code in uniphier_uart_probe()
  tty: n_gsm: Allow ADM response in addition to UA for control dlci
  tty: omap-serial: Fix initial on-boot RTS GPIO level
  tty: serial: jsm: Add one check against NULL pointer dereference
  ...
2018-02-01 09:46:00 -08:00
Gaurav Kohli b027e2298b tty: fix data race between tty_init_dev and flush of buf
There can be a race, if receive_buf call comes before
tty initialization completes in n_tty_open and tty->disc_data
may be NULL.

CPU0					CPU1
----					----
 000|n_tty_receive_buf_common()   	n_tty_open()
-001|n_tty_receive_buf2()		tty_ldisc_open.isra.3()
-002|tty_ldisc_receive_buf(inline)	tty_ldisc_setup()

Using ldisc semaphore lock in tty_init_dev till disc_data
initializes completely.

Signed-off-by: Gaurav Kohli <gkohli@codeaurora.org>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@vger.kernel.org>

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-23 08:57:37 +01:00
Sahara 2b022ab754 pty: cancel pty slave port buf's work in tty_release
In case that CONFIG_SLUB_DEBUG is on and pty is used, races between
release_one_tty and flush_to_ldisc work threads may happen and lead
to use-after-free condition on tty->link->port. Because SLUB_DEBUG
is turned on, freed tty->link->port is filled with POISON_FREE value.
So far without SLUB_DEBUG, port was filled with zero and flush_to_ldisc
could return without a problem by checking if tty is NULL.

CPU 0                                 CPU 1
-----                                 -----
release_tty                           pty_write
   cancel_work_sync(tty)                 to = tty->link
   tty_kref_put(tty->link)               tty_schedule_flip(to->port)
      << workqueue >>                 ...
      release_one_tty                 ...
         pty_cleanup                  ...
            kfree(tty->link->port)       << workqueue >>
                                         flush_to_ldisc
                                            tty = READ_ONCE(port->itty)
                                            tty is 0x6b6b6b6b6b6b6b6b
                                            !!PANIC!! access tty->ldisc

 Unable to handle kernel paging request at virtual address 6b6b6b6b6b6b6b93
 pgd = ffffffc0eb1c3000
 [6b6b6b6b6b6b6b93] *pgd=0000000000000000, *pud=0000000000000000
 ------------[ cut here ]------------
 Kernel BUG at ffffff800851154c [verbose debug info unavailable]
 Internal error: Oops - BUG: 96000004 [#1] PREEMPT SMP
 CPU: 3 PID: 265 Comm: kworker/u8:9 Tainted: G        W 3.18.31-g0a58eeb #1
 Hardware name: Qualcomm Technologies, Inc. MSM 8996pro v1.1 + PMI8996 Carbide (DT)
 Workqueue: events_unbound flush_to_ldisc
 task: ffffffc0ed610ec0 ti: ffffffc0ed624000 task.ti: ffffffc0ed624000
 PC is at ldsem_down_read_trylock+0x0/0x4c
 LR is at tty_ldisc_ref+0x24/0x4c
 pc : [<ffffff800851154c>] lr : [<ffffff800850f6c0>] pstate: 80400145
 sp : ffffffc0ed627cd0
 x29: ffffffc0ed627cd0 x28: 0000000000000000
 x27: ffffff8009e05000 x26: ffffffc0d382cfa0
 x25: 0000000000000000 x24: ffffff800a012f08
 x23: 0000000000000000 x22: ffffffc0703fbc88
 x21: 6b6b6b6b6b6b6b6b x20: 6b6b6b6b6b6b6b93
 x19: 0000000000000000 x18: 0000000000000001
 x17: 00e80000f80d6f53 x16: 0000000000000001
 x15: 0000007f7d826fff x14: 00000000000000a0
 x13: 0000000000000000 x12: 0000000000000109
 x11: 0000000000000000 x10: 0000000000000000
 x9 : ffffffc0ed624000 x8 : ffffffc0ed611580
 x7 : 0000000000000000 x6 : ffffff800a42e000
 x5 : 00000000000003fc x4 : 0000000003bd1201
 x3 : 0000000000000001 x2 : 0000000000000001
 x1 : ffffff800851004c x0 : 6b6b6b6b6b6b6b93

Signed-off-by: Sahara <keun-o.park@darkmatter.ae>

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-19 09:59:51 +01:00
Al Viro afc9a42b74 the rest of drivers/*: annotate ->poll() instances
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-28 11:06:58 -05:00
Al Viro e6c8adca20 anntotate the places where ->poll() return values go
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-27 16:19:53 -05:00
Greg Kroah-Hartman e3b3d0f549 tty: add SPDX identifiers to all remaining files in drivers/tty/
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 <jslaby@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: "Uwe Kleine-König" <kernel@pengutronix.de>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-08 13:08:12 +01:00
Linus Torvalds bf1d6b2c76 Staging/IIO driver updates for 4.14-rc1
Here is the big staging and IIO driver update for 4.14-rc1.
 
 Lots of staging driver fixes and cleanups, including some reorginizing
 of the lustre header files to try to impose some sanity on what is, and
 what is not, the uapi for that filesystem.
 
 There are some tty core changes in here as well, as the speakup drivers
 need them, and that's ok with me, they are sane and the speakup code is
 getting nicer because of it.
 
 There is also the addition of the obiligatory new wifi driver, just
 because it has been a release or two since we added our last one...
 
 Other than that, lots and lots of small coding style fixes, as usual.
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'staging-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pull staging/IIO driver updates from Greg KH:
 "Here is the big staging and IIO driver update for 4.14-rc1.

  Lots of staging driver fixes and cleanups, including some reorginizing
  of the lustre header files to try to impose some sanity on what is,
  and what is not, the uapi for that filesystem.

  There are some tty core changes in here as well, as the speakup
  drivers need them, and that's ok with me, they are sane and the
  speakup code is getting nicer because of it.

  There is also the addition of the obiligatory new wifi driver, just
  because it has been a release or two since we added our last one...

  Other than that, lots and lots of small coding style fixes, as usual.

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

* tag 'staging-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (612 commits)
  staging:rtl8188eu:core Fix remove unneccessary else block
  staging: typec: fusb302: make structure fusb302_psy_desc static
  staging: unisys: visorbus: make two functions static
  staging: fsl-dpaa2/eth: fix off-by-one FD ctrl bitmaks
  staging: r8822be: Simplify deinit_priv()
  staging: r8822be: Remove some dead code
  staging: vboxvideo: Use CONFIG_DRM_KMS_FB_HELPER to check for fbdefio availability
  staging:rtl8188eu Fix comparison to NULL
  staging: rts5208: rename mmc_ddr_tunning_rx_cmd to mmc_ddr_tuning_rx_cmd
  Staging: Pi433: style fix - tabs and spaces
  staging: pi433: fix spelling mistake: "preample" -> "preamble"
  staging:rtl8188eu:core Fix Code Indent
  staging: typec: fusb302: Export current-limit through a power_supply class dev
  staging: typec: fusb302: Add support for USB2 charger detection through extcon
  staging: typec: fusb302: Use client->irq as irq if set
  staging: typec: fusb302: Get max snk mv/ma/mw from device-properties
  staging: typec: fusb302: Set max supply voltage to 5V
  staging: typec: tcpm: Add get_current_limit tcpc_dev callback
  staging:rtl8188eu Use __func__ instead of function name
  staging: lustre: coding style fixes found by checkpatch.pl
  ...
2017-09-05 10:36:26 -07:00
Linus Torvalds e63a94f12b TTY/Serial updates for 4.14-rc1
Here is the big tty/serial driver update for 4.14-rc1.
 
 Well, not all that big, just a number of small serial driver fixes, and
 a new serial driver.  Also in here are some much needed goldfish tty
 driver (emulator) fixes to try to get that codebase under control.
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial updates from Greg KH:
 "Here is the big tty/serial driver update for 4.14-rc1.

  Well, not all that big, just a number of small serial driver fixes,
  and a new serial driver. Also in here are some much needed goldfish
  tty driver (emulator) fixes to try to get that codebase under control.

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

* tag 'tty-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (94 commits)
  tty: goldfish: Implement support for kernel 'earlycon' parameter
  tty: goldfish: Use streaming DMA for r/w operations on Ranchu platforms
  tty: goldfish: Refactor constants to better reflect their nature
  serial: 8250_port: Remove useless NULL checks
  earlycon: initialise baud field of earlycon device structure
  tty: hvcs: make ktermios const
  pty: show associative slave of ptmx in fdinfo
  tty: n_gsm: Add compat_ioctl
  tty: hvcs: constify vio_device_id
  tty: hvc_vio: constify vio_device_id
  tty: mips_ejtag_fdc: constify mips_cdmm_device_id
  Introduce 8250_men_mcb
  mcb: introduce mcb_get_resource()
  serial: imx: Avoid post-PIO cleanup if TX DMA is started
  tty: serial: imx: disable irq after suspend
  serial: 8250_uniphier: add suspend/resume support
  serial: 8250_uniphier: use CHAR register for canary to detect power-off
  serial: 8250_uniphier: fix serial port index in private data
  serial: 8250: of: Add new port type for MediaTek BTIF controller on MT7622/23 SoC
  dt-bindings: serial: 8250: Add MediaTek BTIF controller bindings
  ...
2017-09-05 10:30:48 -07:00
Masatake YAMATO d01c3289e7 pty: show associative slave of ptmx in fdinfo
This patch adds "tty-index" field to /proc/PID/fdinfo/N if N
specifies /dev/ptmx. The field shows the index of associative
slave pts.

Though a minor number is given for each pts instance, ptmx is not.
It means there is no way in user-space to know the association between
file descriptors for pts/n and ptmx. (n = 0, 1, ...)

This is different from pipe. About pipe such association can be solved
by inode of pipefs.

Providing the way to know the association between pts/n and ptmx helps
users understand the status of running system. lsof can utilize this field.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 20:51:23 +02:00
Okash Khawaja a033c3b10a tty: undo export of tty_open_by_driver
Since we have tty_kopen, we no longer need to export tty_open_by_driver.
This patch makes this function static.

Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 16:15:42 +02:00
Okash Khawaja a09ac3974d tty: resolve tty contention between kernel and user space
The commit 12e84c71b7 ("tty: export tty_open_by_driver") exports
tty_open_by_device to allow tty to be opened from inside kernel which
works fine except that it doesn't handle contention with user space or
another kernel-space open of the same tty. For example, opening a tty
from user space while it is kernel opened results in failure and a
kernel log message about mismatch between tty->count and tty's file
open count.

This patch makes kernel access to tty exclusive, so that if a user
process or kernel opens a kernel opened tty, it gets -EBUSY. It does
this by adding TTY_KOPENED flag to tty->flags. When this flag is set,
tty_open_by_driver returns -EBUSY. Instead of overloading
tty_open_by_driver for both kernel and user space, this
patch creates a separate function tty_kopen which closely follows
tty_open_by_driver. tty_kclose closes the tty opened by tty_kopen.

To address the mismatch between tty->count and #fd's, this patch adds
#kopen's to the count before comparing it with tty->count. That way
check_tty_count reflects correct usage count.

Returning -EBUSY on tty open is a change in the interface. I have
tested this with minicom, picocom and commands like "echo foo >
/dev/ttyS0". They all correctly report "Device or resource busy" when
the tty is already kernel opened.

Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 16:15:41 +02:00
Eric W. Biederman 311fc65c9f pty: Repair TIOCGPTPEER
The implementation of TIOCGPTPEER has two issues.

When /dev/ptmx (as opposed to /dev/pts/ptmx) is opened the wrong
vfsmount is passed to dentry_open.  Which results in the kernel displaying
the wrong pathname for the peer.

The second is simply by caching the vfsmount and dentry of the peer it leaves
them open, in a way they were not previously Which because of the inreased
reference counts can cause unnecessary behaviour differences resulting in
regressions.

To fix these move the ioctl into tty_io.c at a generic level allowing
the ioctl to have access to the struct file on which the ioctl is
being called.  This allows the path of the slave to be derived when
opening the slave through TIOCGPTPEER instead of requiring the path to
the slave be cached.  Thus removing the need for caching the path.

A new function devpts_ptmx_path is factored out of devpts_acquire and
used to implement a function devpts_mntget.   The new function devpts_mntget
takes a filp to perform the lookup on and fsi so that it can confirm
that the superblock that is found by devpts_ptmx_path is the proper superblock.

v2: Lots of fixes to make the code actually work
v3: Suggestions by Linus
    - Removed the unnecessary initialization of filp in ptm_open_peer
    - Simplified devpts_ptmx_path as gotos are no longer required

[ This is the fix for the issue that was reverted in commit
  143c97cc65, but this time without breaking 'pbuilder' due to
  increased reference counts   - Linus ]

Fixes: 54ebbfb160 ("tty: add TIOCGPTPEER ioctl")
Reported-by: Christian Brauner <christian.brauner@canonical.com>
Reported-and-tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-24 13:23:03 -07:00
Okash Khawaja fc61ed5127 tty: add function to convert device name to number
The function converts strings like ttyS0 and ttyUSB0 to dev_t like
(4, 64) and (188, 0). It does this by scanning tty_drivers list for
corresponding device name and index. If the driver is not registered,
this function returns -ENODEV. It also acquires tty_mutex.

Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-27 09:08:47 +02:00
Okash Khawaja 12e84c71b7 tty: export tty_open_by_driver
This exports tty_open_by_driver so that it can be called from other
places inside the kernel. The checks for null file pointer are based on
Alan Cox's patch here:
http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1215095.html.
Description below is quoted from it:

"[RFC] tty_port: allow a port to be opened with a tty that has no file handle

    Let us create tty objects entirely in kernel space. Untested proposal to
    show why all the ideas around rewriting half the uart stack are not needed.

    With this a kernel created non file backed tty object could be used to handle
    data, and set terminal modes. Not all ldiscs can cope with this as N_TTY in
    particular has to work back to the fs/tty layer.

    The tty_port code is however otherwise clean of file handles as far as I can
    tell as is the low level tty port write path used by the ldisc, the
    configuration low level interfaces and most of the ldiscs.

    Currently you don't have any exposure to see tty hangups because those are
    built around the file layer. However a) it's a fixed port so you probably
    don't care about that b) if you do we can add a callback and c) you almost
    certainly don't want the userspace tear down/rebuild behaviour anyway.

    This should however be sufficient if we wanted for example to enumerate all
    the bluetooth bound fixed ports via ACPI and make them directly available.

    It doesn't deal with the case of a user opening a port that's also kernel
    opened and that would need some locking out (so it returned EBUSY if bound
    to a kernel device of some kind). That needs resolving along with how you
    "up" or "down" your new bluetooth device, or enumerate it while providing
    the existing tty API to avoid regressions (and to debug)."

The exported funtion is used later in this patch set to gain access to tty_struct.

[changed export symbol level - gkh]

Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 14:04:49 +02:00
Nicolas Pitre a1235b3eb1 tty: split job control support into a file of its own
This makes it easier for job control to become optional and/or usable
independently from tty_io.c, as well as providing a nice purpose
separation. No logical changes from this patch.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18 18:01:52 +02:00
Nicolas Pitre 0c688614dc console: move console_init() out of tty_io.c
All the console driver handling code lives in printk.c.
Move console_init() there as well so console support can still be used
when the TTY code is configured out. No logical changes from this patch.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18 18:01:52 +02:00
Thadeu Lima de Souza Cascardo 87838ae3af tty: fix comment typo s/repsonsible/responsible/
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@cascardo.eti.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-08 18:54:07 +02:00
Johan Hovold 93857edd98 tty: reset termios state on device registration
Free any saved termios data when registering a tty device so that the
termios state is reset when reusing a minor number.

This is useful for hot-pluggable buses such as USB where it does not
make much sense to reuse saved termios data from an unrelated device
when a new device is later plugged in.

This specifically avoids a situation where the new device does not have
the carrier-detect signal wired, but the saved termios state has CLOCAL
cleared, effectively preventing the port from being opened in blocking
mode as noted by Jan Kundrát <jan.kundrat@cesnet.cz>.

Note that clearing the saved data at deregistration would not work as
the device could still be open.

Also note that the termios data is not reset for drivers with
TTY_DRIVER_DYNAMIC_ALLOC set (e.g. legacy pty) as their character device
is registered at driver registration and could theoretically already
have been opened (and pty termios state is never saved anyway).

Reported-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-31 11:37:13 +02:00
Johan Hovold 16b00ae82d tty: drop obsolete termios_locked comments
Drop comments about tty-driver termios_locked structures, which have
been outdated since commit fe6e29fdb1 ("tty: simplify ktermios
allocation").

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-31 11:37:13 +02:00
Johan Hovold 6a7e6f78c2 tty: close race between device register and open
The tty class device is currently not registered until after the
character device has been registered thereby leaving a small window
were a racing open could end up with a NULL tty->dev pointer due to the
class-device lookup failing in alloc_tty_struct.

Close this race by registering the class device before the character
device while making sure to defer the user-space uevent notification
until after the character device has been registered.

Note that some tty drivers expect a valid tty->dev and would misbehave
or crash otherwise. Some line disciplines also currently dereference the
class device unconditionally despite the fact that not every tty is
guaranteed to have one (Unix98 pty), but this is being fixed separately.

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-31 11:37:13 +02:00
Joe Perches d437fa9109 drivers/tty: Convert remaining uses of pr_warning to pr_warn
To enable eventual removal of pr_warning

This makes pr_warn use consistent for drivers/tty

Prior to this patch, there were 2 uses of pr_warning and
23 uses of pr_warn in drivers/tty

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-17 14:14:00 +09:00
Ingo Molnar 299300258d sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h>
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/task.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:35 +01:00
Ingo Molnar 3f07c01441 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:29 +01:00
Alan Cox ed3f0af8c0 tty_port: allow a port to be opened with a tty that has no file handle
Let us create tty objects entirely in kernel space. Untested proposal to
show why all the ideas around rewriting half the uart stack are not needed.

With this a kernel created non file backed tty object could be used to handle
data, and set terminal modes. Not all ldiscs can cope with this as N_TTY in
particular has to work back to the fs/tty layer.

The tty_port code is however otherwise clean of file handles as far as I can
tell as is the low level tty port write path used by the ldisc, the
configuration low level interfaces and most of the ldiscs.

Currently you don't have any exposure to see tty hangups because those are
built around the file layer. However a) it's a fixed port so you probably
don't care about that b) if you do we can add a callback and c) you almost
certainly don't want the userspace tear down/rebuild behaviour anyway.

This should however be sufficient if we wanted for example to enumerate all
the bluetooth bound fixed ports via ACPI and make them directly available.
It doesn't deal with the case of a user opening a port that's also kernel
opened and that would need some locking out (so it returned EBUSY if bound
to a kernel device of some kind). That needs resolving along with how you
"up" or "down" your new bluetooth device, or enumerate it while providing
the existing tty API to avoid regressions (and to debug).

Signed-off-by: Alan Cox <alan@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19 17:22:34 +01:00