Commit Graph

34 Commits

Author SHA1 Message Date
Tejun Heo 3494fc3084 workqueue: dump workqueues on sysrq-t
Workqueues are used extensively throughout the kernel but sometimes
it's difficult to debug stalls involving work items because visibility
into its inner workings is fairly limited.  Although sysrq-t task dump
annotates each active worker task with the information on the work
item being executed, it is challenging to find out which work items
are pending or delayed on which queues and how pools are being
managed.

This patch implements show_workqueue_state() which dumps all busy
workqueues and pools and is called from the sysrq-t handler.  At the
end of sysrq-t dump, something like the following is printed.

 Showing busy workqueues and worker pools:
 ...
 workqueue filler_wq: flags=0x0
   pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=2/256
     in-flight: 491:filler_workfn, 507:filler_workfn
   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256
     in-flight: 501:filler_workfn
     pending: filler_workfn
 ...
 workqueue test_wq: flags=0x8
   pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/1
     in-flight: 510(RESCUER):test_workfn BAR(69) BAR(500)
     delayed: test_workfn1 BAR(492), test_workfn2
 ...
 pool 0: cpus=0 node=0 flags=0x0 nice=0 workers=2 manager: 137
 pool 2: cpus=1 node=0 flags=0x0 nice=0 workers=3 manager: 469
 pool 3: cpus=1 node=0 flags=0x0 nice=-20 workers=2 idle: 16
 pool 8: cpus=0-3 flags=0x4 nice=0 workers=2 manager: 62

The above shows that test_wq is executing test_workfn() on pid 510
which is the rescuer and also that there are two tasks 69 and 500
waiting for the work item to finish in flush_work().  As test_wq has
max_active of 1, there are two work items for test_workfn1() and
test_workfn2() which are delayed till the current work item is
finished.  In addition, pid 492 is flushing test_workfn1().

The work item for test_workfn() is being executed on pwq of pool 2
which is the normal priority per-cpu pool for CPU 1.  The pool has
three workers, two of which are executing filler_workfn() for
filler_wq and the last one is assuming the manager role trying to
create more workers.

This extra workqueue state dump will hopefully help chasing down hangs
involving workqueues.

v3: cpulist_pr_cont() replaced with "%*pbl" printf formatting.

v2: As suggested by Andrew, minor formatting change in pr_cont_work(),
    printk()'s replaced with pr_info()'s, and cpumask printing now
    uses cpulist_pr_cont().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
CC: Ingo Molnar <mingo@redhat.com>
2015-03-09 09:22:28 -04:00
Michal Hocko c32b3cbe0d oom, PM: make OOM detection in the freezer path raceless
Commit 5695be142e ("OOM, PM: OOM killed task shouldn't escape PM
suspend") has left a race window when OOM killer manages to
note_oom_kill after freeze_processes checks the counter.  The race
window is quite small and really unlikely and partial solution deemed
sufficient at the time of submission.

Tejun wasn't happy about this partial solution though and insisted on a
full solution.  That requires the full OOM and freezer's task freezing
exclusion, though.  This is done by this patch which introduces oom_sem
RW lock and turns oom_killer_disable() into a full OOM barrier.

oom_killer_disabled check is moved from the allocation path to the OOM
level and we take oom_sem for reading for both the check and the whole
OOM invocation.

oom_killer_disable() takes oom_sem for writing so it waits for all
currently running OOM killer invocations.  Then it disable all the further
OOMs by setting oom_killer_disabled and checks for any oom victims.
Victims are counted via mark_tsk_oom_victim resp.  unmark_oom_victim.  The
last victim wakes up all waiters enqueued by oom_killer_disable().
Therefore this function acts as the full OOM barrier.

The page fault path is covered now as well although it was assumed to be
safe before.  As per Tejun, "We used to have freezing points deep in file
system code which may be reacheable from page fault." so it would be
better and more robust to not rely on freezing points here.  Same applies
to the memcg OOM killer.

out_of_memory tells the caller whether the OOM was allowed to trigger and
the callers are supposed to handle the situation.  The page allocation
path simply fails the allocation same as before.  The page fault path will
retry the fault (more on that later) and Sysrq OOM trigger will simply
complain to the log.

Normally there wouldn't be any unfrozen user tasks after
try_to_freeze_tasks so the function will not block. But if there was an
OOM killer racing with try_to_freeze_tasks and the OOM victim didn't
finish yet then we have to wait for it. This should complete in a finite
time, though, because

	- the victim cannot loop in the page fault handler (it would die
	  on the way out from the exception)
	- it cannot loop in the page allocator because all the further
	  allocation would fail and __GFP_NOFAIL allocations are not
	  acceptable at this stage
	- it shouldn't be blocked on any locks held by frozen tasks
	  (try_to_freeze expects lockless context) and kernel threads and
	  work queues are not frozen yet

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Suggested-by: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 17:06:03 -08:00
Michal Hocko 401e4a7cf6 sysrq: convert printk to pr_* equivalent
While touching this area let's convert printk to pr_*.  This also makes
the printing of continuation lines done properly.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 17:06:03 -08:00
David Rientjes 8d060bf490 mm, oom: ensure memoryless node zonelist always includes zones
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 <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:21 -07:00
Rik van Riel 722773afd8 sysrq,rcu: suppress RCU stall warnings while sysrq runs
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 <riel@redhat.com>
Suggested-by: Paul McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Madper Xie <cxie@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:17 -07:00
Rik van Riel 984d74a720 sysrq: rcu-ify __handle_sysrq
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 <riel@redhat.com>
Reported-by: Madper Xie <cxie@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:17 -07:00
Borislav Petkov a8fe19ebfb kernel/printk: use symbolic defines for console loglevels
... 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 <bp@suse.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Joe Perches <joe@perches.com>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:54:17 -07:00
Ben Hutchings 8eaede49df sysrq: Allow magic SysRq key functions to be disabled through Kconfig
Turn the initial value of sysctl kernel.sysrq (SYSRQ_DEFAULT_ENABLE)
into a Kconfig variable.

Original version by Bastian Blank <waldi@debian.org>.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-10-16 13:01:44 -07:00
Linus Torvalds 8b8a7df9a1 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
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
  ...
2013-09-07 10:38:46 -07:00
Mathieu J. Poirier 4c076eb0cf Input: sysrq - DT binding for key sequence
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 <mathieu.poirier@linaro.org>
Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2013-08-12 22:31:55 -07:00
Linus Torvalds f5b63ac0f7 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
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
  ...
2013-07-04 15:35:08 -07:00
Dmitry Torokhov 31881d74b6 Merge branch 'for-next' of git://github.com/rydberg/linux into next
Pull in changes from Henrik: "a trivial MT documentation fix".
2013-06-27 23:00:25 -07:00
Mathieu J. Poirier 3d289517df Input: sysrq - request graceful shutdown for key reset
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 <mathieu.poirier@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2013-06-06 12:03:58 -07:00
Jingoo Han 86b40567b9 tty: replace strict_strtoul() with kstrtoul()
The usage of strict_strtoul() is not preferred, because
strict_strtoul() is obsolete. Thus, kstrtoul() should be
used.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-06-03 10:30:42 -07:00
Linus Torvalds 251df49db3 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
Pull input updates from Dmitry Torokhov:
 "Assorted fixes and cleanups to the existing drivers plus a new driver
  for IMS Passenger Control Unit device they use for ther in-flight
  entertainment system."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (44 commits)
  Input: trackpoint - Optimize trackpoint init to use power-on reset
  Input: apbps2 - convert to devm_ioremap_resource()
  Input: ALPS - use %ph to print buffers
  ARM - shmobile: Armadillo800EVA: Move st1232 reset pin handling
  Input: st1232 - add reset pin handling
  Input: st1232 - convert to devm_* infrastructure
  Input: MT - handle semi-mt devices in core
  Input: adxl34x - use spi_get_drvdata()
  Input: ad7877 - use spi_get_drvdata() and spi_set_drvdata()
  Input: ads7846 - use spi_get_drvdata() and spi_set_drvdata()
  Input: ims-pcu - fix a memory leak on error
  Input: sysrq - supplement reset sequence with timeout functionality
  Input: tegra-kbc - support for defining row/columns based on SoC
  Input: imx_keypad - switch to using managed resources
  Input: arc_ps2 - add support for device tree
  Input: mma8450 - fix signed 12bits to 32bits conversion
  Input: eeti_ts - remove redundant null check
  Input: edt-ft5x06 - remove redundant null check before kfree
  Input: ad714x - add CONFIG_PM_SLEEP to suspend/resume functions
  Input: adxl34x - add CONFIG_PM_SLEEP to suspend/resume functions
  ...
2013-05-01 13:20:04 -07:00
Mathieu J. Poirier 3903078677 Input: sysrq - supplement reset sequence with timeout functionality
Some devices have too few buttons, which it makes it hard to have
a reset combo that won't trigger automatically.  As such a
timeout functionality that requires the combination to be held for
a given amount of time before triggering is introduced.

If a key combo is recognized and held for a 'timeout' amount of time,
the system triggers a reset.  If the timeout value is omitted the
driver simply ignores the functionality.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2013-04-01 22:22:19 -07:00
zhangwei(Jovi) afa80ccb4c sysrq: fix inconstistent help message of sysrq key
Currently help message of /proc/sysrq-trigger highlight its
upper-case characters, like below:

      SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E)
      memory-full-oom-kill(F) kill-all-tasks(I) ...

this would confuse user trigger sysrq by upper-case character, which is
inconsistent with the real lower-case character registed key.

This inconsistent help message will also lead more confused when
26 upper-case letters put into use in future.

This patch fix it.

Thanks the comments from Andrew and Randy.

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-15 14:06:45 -07:00
Linus Torvalds adf96e6f51 sysrq: don't depend on weak undefined arrays to have an address that compares as NULL
When taking an address of an extern array, gcc quite naturally should be
able to say "an address of an object can never be NULL" and just
optimize away the test entirely.

However, the new alternate sysrq reset code (commit 154b7a489a5b:
"Input: sysrq - allow specifying alternate reset sequence") did exactly
that, and declared platform_sysrq_reset_seq[] as a weak array, and
expecting that testing the address of the array would show whether it
actually got linked against something or not.

And that doesn't work with all gcc versions.  Clearly it works with
*some* versions of gcc, and maybe it's even supposed to work, but it
really is a very fragile concept.

So instead of testing the address of the weak variable, just create a
weak instance of that array that is empty.  If some platform then has a
real platform_sysrq_reset_seq[] that overrides our weak one, the linker
will switch to that one, and it all works without any run-time
conditionals at all.

Reported-by: Dave Airlie <airlied@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 09:59:50 -08:00
Linus Torvalds c6699b58f4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
Pull input updates from Dmitry Torokhov:
 "Two new touchpad drivers - Cypress APA I2C Trackpad and Cypress PS/2
  touchpad and a big update to ALPS driver from Kevin Cernekee that adds
  support for "Rushmore" touchpads and paves way for adding support for
  "Dolphin" touchpads.

  There is also a new input driver for Goldfish emulator and also
  Android keyreset driver was folded into SysRq code.

  A few more drivers were updated with device tree bindings and others
  got some small cleanups and fixes."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (55 commits)
  Input: cyttsp-spi - remove duplicate MODULE_ALIAS()
  Input: tsc2005 - add MODULE_ALIAS
  Input: tegra-kbc - require CONFIG_OF, remove platform data
  Input: synaptics - initialize pointer emulation usage
  Input: MT - do not apply filtering on emulated events
  Input: bma150 - make some defines public and fix some comments
  Input: bma150 - fix checking pm_runtime_get_sync() return value
  Input: ALPS - enable trackstick on Rushmore touchpads
  Input: ALPS - add support for "Rushmore" touchpads
  Input: ALPS - make the V3 packet field decoder "pluggable"
  Input: ALPS - move pixel and bitmap info into alps_data struct
  Input: ALPS - fix command mode check
  Input: ALPS - rework detection of Pinnacle AGx touchpads
  Input: ALPS - move {addr,nibble}_command settings into alps_set_defaults()
  Input: ALPS - use function pointers for different protocol handlers
  Input: ALPS - rework detection sequence
  Input: ALPS - introduce helper function for repeated commands
  Input: ALPS - move alps_get_model() down below hw_init code
  Input: ALPS - copy "model" info into alps_data struct
  Input: ALPS - document the alps.h data structures
  ...
2013-02-20 11:00:43 -08:00
Clark Williams 8bd75c77b7 sched/rt: Move rt specific bits into new header file
Move rt scheduler definitions out of include/linux/sched.h into
new file include/linux/sched/rt.h

Signed-off-by: Clark Williams <williams@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20130207094707.7b9f825f@riff.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-02-07 20:51:08 +01:00
Mathieu Poirier 154b7a489a Input: sysrq - allow specifying alternate reset sequence
This patch adds keyreset functionality to the sysrq driver. It allows
certain button/key combinations to be used in order to trigger emergency
reboots.

Redefining the '__weak platform_sysrq_reset_seq' variable is required
to trigger the feature.  Alternatively keys can be passed to the driver
via a module parameter.

This functionality comes from the keyreset driver submitted by
Arve Hjønnevåg in the Android kernel.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2013-01-17 00:27:52 -08:00
David Rientjes 5318609519 mm, oom: ensure sysrq+f always passes valid zonelist
With hotpluggable and memoryless nodes, it's possible that node 0 will
not be online, so use the first online node's zonelist rather than
hardcoding node 0 to pass a zonelist with all zones to the oom killer.

Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-15 17:13:48 -08:00
David S. Miller 916ca14aaf sparc64: Add global PMU register dumping via sysrq.
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-10-16 09:34:01 -07:00
Anton Vorontsov b82c32872d sysrq: use SEND_SIG_FORCED instead of force_sig()
Change send_sig_all() to use do_send_sig_info(SEND_SIG_FORCED) instead
of force_sig(SIGKILL).  With the recent changes we do not need force_ to
kill the CLONE_NEWPID tasks.

And this is more correct.  force_sig() can race with the exiting thread,
while do_send_sig_info(group => true) kill the whole process.

Some more notes from Oleg Nesterov:

> Just one note. This change makes no difference for sysrq_handle_kill().
> But it obviously changes the behaviour sysrq_handle_term(). I think
> this is fine, if you want to really kill the task which blocks/ignores
> SIGTERM you can use sysrq_handle_kill().
>
> Even ignoring the reasons why force_sig() is simply wrong here,
> force_sig(SIGTERM) looks strange. The task won't be killed if it has
> a handler, but SIG_IGN can't help. However if it has the handler
> but blocks SIGTERM temporary (this is very common) it will be killed.

Also,

> force_sig() can't kill the process if the main thread has already
> exited. IOW, it is trivial to create the process which can't be
> killed by sysrq.

So, this patch fixes the issue.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-05 15:25:50 -07:00
David Rientjes 08ab9b10d4 mm, oom: force oom kill on sysrq+f
The oom killer chooses not to kill a thread if:

 - an eligible thread has already been oom killed and has yet to exit,
   and

 - an eligible thread is exiting but has yet to free all its memory and
   is not the thread attempting to currently allocate memory.

SysRq+F manually invokes the global oom killer to kill a memory-hogging
task.  This is normally done as a last resort to free memory when no
progress is being made or to test the oom killer itself.

For both uses, we always want to kill a thread and never defer.  This
patch causes SysRq+F to always kill an eligible thread and can be used to
force a kill even if another oom killed thread has failed to exit.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-21 17:54:58 -07:00
Alan Cox 079c9534a9 vt:tackle kbd_table
Keyboard struct lifetime is easy, but the locking is not and is completely
ignored by the existing code. Tackle this one head on

- Make the kbd_table private so we can run down all direct users
- Hoick the relevant ioctl handlers into the keyboard layer
- Lock them with the keyboard lock so they don't change mid keypress
- Add helpers for things like console stop/start so we isolate the poking
  around properly
- Tweak the braille console so it still builds

There are a couple of FIXME locking cases left for ioctls that are so hideous
they should be addressed in a later patch. After this patch the kbd_table is
private and all the keyboard jiggery pokery is in one place.

This update fixes speakup and also a memory leak in the original.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-03-08 10:50:35 -08:00
Anton Vorontsov d3a532a9c6 sysrq: Properly check for kernel threads
There's a real possibility of killing kernel threads that might
have issued use_mm(), so kthread's mm might become non-NULL.

This patch fixes the issue by checking for PF_KTHREAD (just as
get_task_mm()).

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-02-09 09:03:30 -08:00
Anton Vorontsov e502babe0a sysrq: Fix possible race with exiting task
sysrq should grab the tasklist lock, otherwise calling force_sig() is
not safe, as it might race with exiting task, which ->sighand might be
set to NULL already.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-02-09 09:03:29 -08:00
Al Viro ff01bb4832 fs: move code out of buffer.c
Move invalidate_bdev, block_sync_page into fs/block_dev.c.  Export
kill_bdev as well, so brd doesn't have to open code it.  Reduce
buffer_head.h requirement accordingly.

Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving.  The small comment replacing it says enough.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:54:07 -05:00
David Rientjes b2b755b5f1 lib, arch: add filter argument to show_mem and fix private implementations
Commit ddd588b5dd ("oom: suppress nodes that are not allowed from
meminfo on oom kill") moved lib/show_mem.o out of lib/lib.a, which
resulted in build warnings on all architectures that implement their own
versions of show_mem():

	lib/lib.a(show_mem.o): In function `show_mem':
	show_mem.c:(.text+0x1f4): multiple definition of `show_mem'
	arch/sparc/mm/built-in.o:(.text+0xd70): first defined here

The fix is to remove __show_mem() and add its argument to show_mem() in
all implementations to prevent this breakage.

Architectures that implement their own show_mem() actually don't do
anything with the argument yet, but they could be made to filter nodes
that aren't allowed in the current context in the future just like the
generic implementation.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: James Bottomley <James.Bottomley@hansenpartnership.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24 17:49:37 -07:00
Linus Torvalds 87450bd55d Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: matrix_keypad - increase the limit of rows and columns
  Input: wacom - fix error path in wacom_probe()
  Input: ads7846 - check proper condition when freeing gpio
  Revert "Input: do not pass injected events back to the originating handler"
  Input: sysrq - rework re-inject logic
  Input: serio - clear pending rescans after sysfs driver rebind
  Input: rotary_encoder - use proper irqflags
  Input: wacom_w8001 - report resolution to userland
2011-02-15 09:40:27 -08:00
Linus Torvalds 6fb1b30425 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: wacom - pass touch resolution to clients through input_absinfo
  Input: wacom - add 2 Bamboo Pen and touch models
  Input: sysrq - ensure sysrq_enabled and __sysrq_enabled are consistent
  Input: sparse-keymap - fix KEY_VSW handling in sparse_keymap_setup
  Input: tegra-kbc - add tegra keyboard driver
  Input: gpio_keys - switch to using request_any_context_irq
  Input: serio - allow registered drivers to get status flag
  Input: ct82710c - return proper error code for ct82c710_open
  Input: bu21013_ts - added regulator support
  Input: bu21013_ts - remove duplicate resolution parameters
  Input: tnetv107x-ts - don't treat NULL clk as an error
  Input: tnetv107x-keypad - don't treat NULL clk as an error

Fix up trivial conflicts in drivers/input/keyboard/Makefile due to
additions of tc3589x/Tegra drivers
2011-01-26 16:31:44 +10:00
Linus Torvalds 864ee6cb22 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: fix typo in keycode validation supporting large scancodes
  Input: aiptek - tighten up permissions on sysfs attributes
  Input: sysrq - pass along lone Alt + SysRq
2010-11-19 10:31:04 -08:00
Greg Kroah-Hartman 96fd7ce58f TTY: create drivers/tty and move the tty core files there
The tty code should be in its own subdirectory and not in the char
driver with all of the cruft that is currently there.

Based on work done by Arnd Bergmann <arnd@arndb.de>

Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-11-05 08:10:33 -07:00