linux-stable.git/drivers/tty/tty_io.c, branch v6.4

Merge tag 'driver-core-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2023-04-27T18:53:57+00:00

Pull driver core updates from Greg KH:
 "Here is the large set of driver core changes for 6.4-rc1.

  Once again, a busy development cycle, with lots of changes happening
  in the driver core in the quest to be able to move "struct bus" and
  "struct class" into read-only memory, a task now complete with these
  changes.

  This will make the future rust interactions with the driver core more
  "provably correct" as well as providing more obvious lifetime rules
  for all busses and classes in the kernel.

  The changes required for this did touch many individual classes and
  busses as many callbacks were changed to take const * parameters
  instead. All of these changes have been submitted to the various
  subsystem maintainers, giving them plenty of time to review, and most
  of them actually did so.

  Other than those changes, included in here are a small set of other
  things:

   - kobject logging improvements

   - cacheinfo improvements and updates

   - obligatory fw_devlink updates and fixes

   - documentation updates

   - device property cleanups and const * changes

   - firwmare loader dependency fixes.

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

* tag 'driver-core-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (120 commits)
  device property: make device_property functions take const device *
  driver core: update comments in device_rename()
  driver core: Don't require dynamic_debug for initcall_debug probe timing
  firmware_loader: rework crypto dependencies
  firmware_loader: Strip off \n from customized path
  zram: fix up permission for the hot_add sysfs file
  cacheinfo: Add use_arch[|_cache]_info field/function
  arch_topology: Remove early cacheinfo error message if -ENOENT
  cacheinfo: Check cache properties are present in DT
  cacheinfo: Check sib_leaf in cache_leaves_are_shared()
  cacheinfo: Allow early level detection when DT/ACPI info is missing/broken
  cacheinfo: Add arm64 early level initializer implementation
  cacheinfo: Add arch specific early level initializer
  tty: make tty_class a static const structure
  driver core: class: remove struct class_interface * from callbacks
  driver core: class: mark the struct class in struct class_interface constant
  driver core: class: make class_register() take a const *
  driver core: class: mark class_release() as taking a const *
  driver core: remove incorrect comment for device_create*
  MIPS: vpe-cmp: remove module owner pointer from struct class usage.
  ...

tty: make tty_class a static const structure

2023-04-03T19:43:07+00:00

Now that the driver core allows for struct class to be in read-only
memory, move the tty_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: "Ilpo Järvinen" 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/r/2023040250-landowner-unfitted-11f4@gregkh
Signed-off-by: Greg Kroah-Hartman

tty: Prevent writing chars during tcsetattr TCSADRAIN/FLUSH

2023-03-29T08:55:53+00:00

If userspace races tcsetattr() with a write, the drained condition
might not be guaranteed by the kernel. There is a race window after
checking Tx is empty before tty_set_termios() takes termios_rwsem for
write. During that race window, more characters can be queued by a
racing writer.

Any ongoing transmission might produce garbage during HW's
->set_termios() call. The intent of TCSADRAIN/FLUSH seems to be
preventing such a character corruption. If those flags are set, take
tty's write lock to stop any writer before performing the lower layer
Tx empty check and wait for the pending characters to be sent (if any).

The initial wait for all-writers-done must be placed outside of tty's
write lock to avoid deadlock which makes it impossible to use
tty_wait_until_sent(). The write lock is retried if a racing write is
detected.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20230317113318.31327-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

driver core: class: remove module * from class_create()

2023-03-17T14:16:33+00:00

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
something.  So just remove it and fix up all callers of the function in
the kernel tree at the same time.

Cc: "Rafael J. Wysocki" 
Acked-by: Benjamin Tissoires 
Link: https://lore.kernel.org/r/20230313181843.1207845-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

tty: simplify sysctl registration

2023-03-09T16:15:49+00:00

register_sysctl_table() is a deprecated compatibility wrapper.
register_sysctl_init() can do the directory creation for you so just use
that

Signed-off-by: Luis Chamberlain 
Link: https://lore.kernel.org/r/20230302204612.782387-7-mcgrof@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: fix out-of-bounds access in tty_driver_lookup_tty()

2023-01-19T14:04:56+00:00

When specifying an invalid console= device like console=tty3270,
tty_driver_lookup_tty() returns the tty struct without checking
whether index is a valid number.

To reproduce:

qemu-system-x86_64 -enable-kvm -nographic -serial mon:stdio \
-kernel ../linux-build-x86/arch/x86/boot/bzImage \
-append "console=ttyS0 console=tty3270"

This crashes with:

[    0.770599] BUG: kernel NULL pointer dereference, address: 00000000000000ef
[    0.771265] #PF: supervisor read access in kernel mode
[    0.771773] #PF: error_code(0x0000) - not-present page
[    0.772609] Oops: 0000 [#1] PREEMPT SMP PTI
[    0.774878] RIP: 0010:tty_open+0x268/0x6f0
[    0.784013]  chrdev_open+0xbd/0x230
[    0.784444]  ? cdev_device_add+0x80/0x80
[    0.784920]  do_dentry_open+0x1e0/0x410
[    0.785389]  path_openat+0xca9/0x1050
[    0.785813]  do_filp_open+0xaa/0x150
[    0.786240]  file_open_name+0x133/0x1b0
[    0.786746]  filp_open+0x27/0x50
[    0.787244]  console_on_rootfs+0x14/0x4d
[    0.787800]  kernel_init_freeable+0x1e4/0x20d
[    0.788383]  ? rest_init+0xc0/0xc0
[    0.788881]  kernel_init+0x11/0x120
[    0.789356]  ret_from_fork+0x22/0x30

Signed-off-by: Sven Schnelle 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20221209112737.3222509-2-svens@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman

Merge tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2022-12-16T11:54:54+00:00

Pull driver core updates from Greg KH:
 "Here is the set of driver core and kernfs changes for 6.2-rc1.

  The "big" change in here is the addition of a new macro,
  container_of_const() that will preserve the "const-ness" of a pointer
  passed into it.

  The "problem" of the current container_of() macro is that if you pass
  in a "const *", out of it can comes a non-const pointer unless you
  specifically ask for it. For many usages, we want to preserve the
  "const" attribute by using the same call. For a specific example, this
  series changes the kobj_to_dev() macro to use it, allowing it to be
  used no matter what the const value is. This prevents every subsystem
  from having to declare 2 different individual macros (i.e.
  kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce
  the const value at build time, which having 2 macros would not do
  either.

  The driver for all of this have been discussions with the Rust kernel
  developers as to how to properly mark driver core, and kobject,
  objects as being "non-mutable". The changes to the kobject and driver
  core in this pull request are the result of that, as there are lots of
  paths where kobjects and device pointers are not modified at all, so
  marking them as "const" allows the compiler to enforce this.

  So, a nice side affect of the Rust development effort has been already
  to clean up the driver core code to be more obvious about object
  rules.

  All of this has been bike-shedded in quite a lot of detail on lkml
  with different names and implementations resulting in the tiny version
  we have in here, much better than my original proposal. Lots of
  subsystem maintainers have acked the changes as well.

  Other than this change, included in here are smaller stuff like:

   - kernfs fixes and updates to handle lock contention better

   - vmlinux.lds.h fixes and updates

   - sysfs and debugfs documentation updates

   - device property updates

  All of these have been in the linux-next tree for quite a while with
  no problems"

* tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (58 commits)
  device property: Fix documentation for fwnode_get_next_parent()
  firmware_loader: fix up to_fw_sysfs() to preserve const
  usb.h: take advantage of container_of_const()
  device.h: move kobj_to_dev() to use container_of_const()
  container_of: add container_of_const() that preserves const-ness of the pointer
  driver core: fix up missed drivers/s390/char/hmcdrv_dev.c class.devnode() conversion.
  driver core: fix up missed scsi/cxlflash class.devnode() conversion.
  driver core: fix up some missing class.devnode() conversions.
  driver core: make struct class.devnode() take a const *
  driver core: make struct class.dev_uevent() take a const *
  cacheinfo: Remove of_node_put() for fw_token
  device property: Add a blank line in Kconfig of tests
  device property: Rename goto label to be more precise
  device property: Move PROPERTY_ENTRY_BOOL() a bit down
  device property: Get rid of __PROPERTY_ENTRY_ARRAY_EL*SIZE*()
  kernfs: fix all kernel-doc warnings and multiple typos
  driver core: pass a const * into of_device_uevent()
  kobject: kset_uevent_ops: make name() callback take a const *
  kobject: kset_uevent_ops: make filter() callback take a const *
  kobject: make kobject_namespace take a const *
  ...

Merge tag 'tty-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2022-12-16T11:31:56+00:00

Pull tty/serial driver updates from Greg KH:
 "Here is the "big" set of tty/serial driver changes for 6.2-rc1.

  As in previous kernel releases, nothing big here at all, just some
  small incremental serial/tty layer cleanups and some individual driver
  additions and fixes. Highlights are:

   - serial helper macros from Jiri Slaby to reduce the amount of
     duplicated code in serial drivers

   - api cleanups and consolidations from Ilpo Järvinen in lots of
     serial drivers

   - the usual set of n_gsm fixes from Daniel Starke as that code gets
     exercised more

   - TIOCSTI is finally able to be disabled if requested (security
     hardening feature from Kees Cook)

   - fsl_lpuart driver fixes and features added

   - other small serial driver additions and fixes

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

* tag 'tty-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (97 commits)
  serial: atmel: don't stop the transmitter when doing PIO
  serial: atmel: cleanup atmel_start+stop_tx()
  tty: serial: fsl_lpuart: switch to new dmaengine_terminate_* API
  serial: sunsab: Fix error handling in sunsab_init()
  serial: altera_uart: fix locking in polling mode
  serial: pch: Fix PCI device refcount leak in pch_request_dma()
  tty: serial: fsl_lpuart: Use pm_ptr() to avoid need to make pm __maybe_unused
  tty: serial: fsl_lpuart: Add runtime pm support
  tty: serial: fsl_lpuart: enable wakeup source for lpuart
  serdev: Replace poll loop by readx_poll_timeout() macro
  tty: synclink_gt: unwind actions in error path of net device open
  serial: stm32: move dma_request_chan() before clk_prepare_enable()
  dt-bindings: serial: xlnx,opb-uartlite: Drop 'contains' from 'xlnx,use-parity'
  serial: pl011: Do not clear RX FIFO & RX interrupt in unthrottle.
  serial: amba-pl011: avoid SBSA UART accessing DMACR register
  tty: serial: altera_jtaguart: remove struct altera_jtaguart
  tty: serial: altera_jtaguart: use uart_port::read_status_mask
  tty: serial: altera_jtaguart: remove unused altera_jtaguart::sigs
  tty: serial: altera_jtaguart: remove flag from altera_jtaguart_rx_chars()
  n_tty: Rename tail to old_tail in n_tty_read()
  ...

tty: tty_io: use console_list_lock for list synchronization

2022-12-02T10:25:02+00:00

show_cons_active() uses the console_lock to gather information
on registered consoles. It requires that no consoles are unregistered
until it is finished. The console_list_lock should be used because
list synchronization responsibility will be removed from the
console_lock in a later change.

Note, the console_lock is still needed to serialize the device()
callback with other console operations.

Signed-off-by: John Ogness 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Petr Mladek 
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/20221116162152.193147-34-john.ogness@linutronix.de

tty: tty_io: document console_lock usage

2022-12-02T10:25:00+00:00

show_cons_active() uses the console_lock to gather information
on registered consoles. Since the console_lock is being used for
multiple reasons, explicitly document these reasons. This will
be useful when the console_lock is split into fine-grained
locking.

Signed-off-by: John Ogness 
Reviewed-by: Petr Mladek 
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/20221116162152.193147-10-john.ogness@linutronix.de