linux-stable.git/drivers/tty/sysrq.c, branch linux-3.19.y

mm, oom: ensure memoryless node zonelist always includes zones

2014-08-07T01:01:21+00:00

With memoryless node support being worked on, it's possible that for
optimizations that a node may not have a non-NULL zonelist.  When
CONFIG_NUMA is enabled and node 0 is memoryless, this means the zonelist
for first_online_node may become NULL.

The oom killer requires a zonelist that includes all memory zones for
the sysrq trigger and pagefault out of memory handler.

Ensure that a non-NULL zonelist is always passed to the oom killer.

[akpm@linux-foundation.org: fix non-numa build]
Signed-off-by: David Rientjes 
Cc: "Kirill A. Shutemov" 
Cc: Johannes Weiner 
Cc: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sysrq,rcu: suppress RCU stall warnings while sysrq runs

2014-06-06T23:08:17+00:00

Some sysrq handlers can run for a long time, because they dump a lot of
data onto a serial console.  Having RCU stall warnings pop up in the
middle of them only makes the problem worse.

This patch temporarily disables RCU stall warnings while a sysrq request
is handled.

Signed-off-by: Rik van Riel 
Suggested-by: Paul McKenney 
Signed-off-by: Paul E. McKenney 
Cc: Madper Xie 
Cc: Randy Dunlap 
Cc: Richard Weinberger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sysrq: rcu-ify __handle_sysrq

2014-06-06T23:08:17+00:00

Echoing values into /proc/sysrq-trigger seems to be a popular way to get
information out of the kernel.  However, dumping information about
thousands of processes, or hundreds of CPUs to serial console can result
in IRQs being blocked for minutes, resulting in various kinds of cascade
failures.

The most common failure is due to interrupts being blocked for a very
long time.  This can lead to things like failed IO requests, and other
things the system cannot easily recover from.

This problem is easily fixable by making __handle_sysrq use RCU instead
of spin_lock_irqsave.

This leaves the warning that RCU grace periods have not elapsed for a
long time, but the system will come back from that automatically.

It also leaves sysrq-from-irq-context when the sysrq keys are pressed,
but that is probably desired since people want that to work in
situations where the system is already hosed.

The callers of register_sysrq_key and unregister_sysrq_key appear to be
capable of sleeping.

Signed-off-by: Rik van Riel 
Reported-by: Madper Xie 
Cc: Randy Dunlap 
Cc: Richard Weinberger 
Cc: Paul E. McKenney 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel/printk: use symbolic defines for console loglevels

2014-06-04T23:54:17+00:00

... instead of naked numbers.

Stuff in sysrq.c used to set it to 8 which is supposed to mean above
default level so set it to DEBUG instead as we're terminating/killing all
tasks and we want to be verbose there.

Also, correct the check in x86_64_start_kernel which should be >= as
we're clearly issuing the string there for all debug levels, not only
the magical 10.

Signed-off-by: Borislav Petkov 
Acked-by: Kees Cook 
Acked-by: Randy Dunlap 
Cc: Joe Perches 
Cc: Valdis Kletnieks 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sysrq: Allow magic SysRq key functions to be disabled through Kconfig

2013-10-16T20:01:44+00:00

Turn the initial value of sysctl kernel.sysrq (SYSRQ_DEFAULT_ENABLE)
into a Kconfig variable.

Original version by Bastian Blank .

Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

2013-09-07T17:38:46+00:00

Pull input updates from Dmitry Torokhov:
 "A new driver for slidebar on Ideapad laptops and a bunch of assorted
  driver fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (32 commits)
  Input: add SYN_MAX and SYN_CNT constants
  Input: max11801_ts - convert to devm
  Input: egalax-ts - fix typo and improve text
  Input: MAINTAINERS - change maintainer for cyttsp driver
  Input: cyttsp4 - kill 'defined but not used' compiler warnings
  Input: add driver for slidebar on Lenovo IdeaPad laptops
  Input: omap-keypad - set up irq type from DT
  Input: omap-keypad - enable wakeup capability for keypad.
  Input: omap-keypad - clear interrupts on open
  Input: omap-keypad - convert to threaded IRQ
  Input: omap-keypad - use bitfiled instead of hardcoded values
  Input: cyttsp4 - remove useless NULL test from cyttsp4_watchdog_timer()
  Input: wacom - fix error return code in wacom_probe()
  Input: as5011 - fix error return code in as5011_probe()
  Input: keyboard, serio - simplify use of devm_ioremap_resource
  Input: tegra-kbc - simplify use of devm_ioremap_resource
  Input: htcpen - fix incorrect placement of __initdata
  Input: qt1070 - add power management ops
  Input: wistron_btns - add MODULE_DEVICE_TABLE
  Input: wistron_btns - mark the Medion MD96500 keymap as tested
  ...

Input: sysrq - DT binding for key sequence

2013-08-13T05:31:55+00:00

Adding a simple device tree binding for the specification of key
sequences. Definition of the keys found in the sequence are located in
'include/uapi/linux/input.h'.

For the sysrq driver, holding the sequence of keys down for a specific
amount of time will reset the system.

Signed-off-by: Mathieu Poirier 
Acked-by: Grant Likely 
Signed-off-by: Dmitry Torokhov

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

2013-07-04T22:35:08+00:00

Pull input updates from Dmitry Torokhov:
 "First round of updates for the input subsystem.

  You will get a new touchsreen driver for Cypress 4th generation
  devices, a driver for a special controller implementing PS/2 protocol
  in OLPC devices, and a driver for power key for SiRFprimaII PWRC.

  HID and bcm5497 now support for the 2013 MacBook Air.

  EVIOCGKEY and the rest of evdev ioctls now flush events of matching
  type from the client's event queue so that clients can be sure any
  events received after issuing EVIOCG* ioctl are new events.

  And a host of cleanups and improvements in other drivers"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (87 commits)
  Input: cyttsp4 - kfree xfer_buf on error path in probe()
  Input: tps6507x-ts - select INPUT_POLLDEV
  Input: bcm5974 - add support for the 2013 MacBook Air
  HID: apple: Add support for the 2013 Macbook Air
  Input: cyttsp4 - leak on error path in probe()
  Input: cyttsp4 - silence NULL dereference warning
  Input: cyttsp4 - silence shift wrap warning
  Input: tps6507x-ts - convert to polled input device infrastructure
  ARM: davinci: da850-evm: remove vref from touchscreen platform data
  Input: cyttsp4 - SPI driver for Cypress TMA4XX touchscreen devices
  Input: cyttsp4 - I2C driver for Cypress TMA4XX touchscreen devices
  Input: cyttsp4 - add core driver for Cypress TMA4XX touchscreen devices
  Input: cyttsp - I2C driver split into two modules
  Input: add OLPC AP-SP driver
  Input: nspire-keypad - remove redundant dev_err call in nspire_keypad_probe()
  Input: tps6507x-ts - remove vref from platform data
  Input: tps6507x-ts - use bool for booleans
  Input: tps6507x-ts - remove bogus unreachable code
  Input: samsung-keypad - let device core setup the default pin configuration
  Input: wacom_i2c - implement hovering capability
  ...

Merge branch 'for-next' of git://github.com/rydberg/linux into next

2013-06-28T06:00:25+00:00

Pull in changes from Henrik: "a trivial MT documentation fix".

Input: sysrq - request graceful shutdown for key reset

2013-06-06T19:03:58+00:00

Attempt to reboot the system gracefully when a key combo is detected.
If the reste combination is pressed the 2nd time we assume that graceful
reboot failed and perform emergency reboot. This fucntionality is useful
when UI is stuck but the system is otherwise working fine.

Signed-off-by: Mathieu Poirier 
Signed-off-by: Dmitry Torokhov