linux-toradex.git/kernel/time/alarmtimer.c, branch v4.8-rc6

alarmtimer: Fix comments describing structure fields

2016-06-20T19:47:09+00:00

Updated struct alarm and struct alarm_timer descriptions.

Cc: Prarit Bhargava 
Cc: Richard Cochran 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Signed-off-by: Pratyush Patel 
Signed-off-by: John Stultz

alarmtimer: Avoid unexpected rtc interrupt when system resume from S3

2015-12-04T06:31:42+00:00

Before the system go to suspend (S3), if user create a timer
with clockid CLOCK_REALTIME_ALARM/CLOCK_BOOTTIME_ALARM and set a
"large" timeout value to this timer. The function
alarmtimer_suspend will be called to setup a timeout value to
RTC timer to avoid the system sleep over time. However, if the
system wakeup early than RTC timeout, the RTC timer will not be
cleared. And this will cause the hpet_rtc_interrupt come
unexpectedly until the RTC timeout. To fix this problem, just
adding alarmtimer_resume to cancel the RTC timer.

This was noticed because the HPET RTC emulation fires an
interrupt every 16ms(=1/2^DEFAULT_RTC_SHIFT) up to the point
where the alarm time is reached.

This program always hits this situation
(https://lkml.org/lkml/2015/11/8/326), if system wake up earlier
than alarm time.

Cc: Thomas Gleixner 
Cc: John Stultz 
Signed-off-by: Zhuo-hao Lee 
[jstultz: Tweak commit subject & formatting slightly]
Signed-off-by: John Stultz

alarmtimer: Get rid of unused return value

2015-04-22T15:06:52+00:00

We want to get rid of the hrtimer_start() return value and the alarm
timer return value is nowhere used. Remove it.

Signed-off-by: Thomas Gleixner 
Acked-by: Peter Zijlstra 
Cc: Preeti U Murthy 
Cc: Viresh Kumar 
Cc: Marcelo Tosatti 
Cc: Frederic Weisbecker 
Cc: John Stultz 
Link: http://lkml.kernel.org/r/20150414203503.243910615@linutronix.de
Signed-off-by: Thomas Gleixner

hrtimer: Get rid of hrtimer_get_res()

2015-04-22T15:06:49+00:00

The resolution is directly accessible now. So its simpler just to fill
in the values of the timespec and be done with it.

Text size reduction (combined with "hrtimer: Get rid of the resolution
field in hrtimer_clock_base"):
       x8664 -61, i386 -221, ARM -60, power64 -48

Signed-off-by: Thomas Gleixner 
Acked-by: Peter Zijlstra 
Cc: Preeti U Murthy 
Cc: Viresh Kumar 
Cc: Marcelo Tosatti 
Cc: Frederic Weisbecker 
Link: http://lkml.kernel.org/r/20150414203500.879888080@linutronix.de
Signed-off-by: Thomas Gleixner

all arches, signal: move restart_block to struct task_struct

2015-02-13T02:54:12+00:00

If an attacker can cause a controlled kernel stack overflow, overwriting
the restart block is a very juicy exploit target.  This is because the
restart_block is held in the same memory allocation as the kernel stack.

Moving the restart block to struct task_struct prevents this exploit by
making the restart_block harder to locate.

Note that there are other fields in thread_info that are also easy
targets, at least on some architectures.

It's also a decent simplification, since the restart code is more or less
identical on all architectures.

[james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
Signed-off-by: Andy Lutomirski 
Cc: Thomas Gleixner 
Cc: Al Viro 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Kees Cook 
Cc: David Miller 
Acked-by: Richard Weinberger 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Vineet Gupta 
Cc: Russell King 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Haavard Skinnemoen 
Cc: Hans-Christian Egtvedt 
Cc: Steven Miao 
Cc: Mark Salter 
Cc: Aurelien Jacquiot 
Cc: Mikael Starvik 
Cc: Jesper Nilsson 
Cc: David Howells 
Cc: Richard Kuo 
Cc: "Luck, Tony" 
Cc: Geert Uytterhoeven 
Cc: Michal Simek 
Cc: Ralf Baechle 
Cc: Jonas Bonn 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Acked-by: Michael Ellerman  (powerpc)
Tested-by: Michael Ellerman  (powerpc)
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Chen Liqin 
Cc: Lennox Wu 
Cc: Chris Metcalf 
Cc: Guan Xuetao 
Cc: Chris Zankel 
Cc: Max Filippov 
Cc: Oleg Nesterov 
Cc: Guenter Roeck 
Signed-off-by: James Hogan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

alarmtimer: Lock k_itimer during timer callback

2014-09-12T20:59:12+00:00

Locks the k_itimer's it_lock member when handling the alarm timer's
expiry callback.

The regular posix timers defined in posix-timers.c have this lock held
during timout processing because their callbacks are routed through
posix_timer_fn().  The alarm timers follow a different path, so they
ought to grab the lock somewhere else.

Cc: stable@vger.kernel.org
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Richard Cochran 
Cc: Prarit Bhargava 
Cc: Sharvil Nanavati 
Signed-off-by: Richard Larocque 
Signed-off-by: John Stultz

alarmtimer: Do not signal SIGEV_NONE timers

2014-09-12T20:59:12+00:00

Avoids sending a signal to alarm timers created with sigev_notify set to
SIGEV_NONE by checking for that special case in the timeout callback.

The regular posix timers avoid sending signals to SIGEV_NONE timers by
not scheduling any callbacks for them in the first place.  Although it
would be possible to do something similar for alarm timers, it's simpler
to handle this as a special case in the timeout.

Prior to this patch, the alarm timer would ignore the sigev_notify value
and try to deliver signals to the process anyway.  Even worse, the
sanity check for the value of sigev_signo is skipped when SIGEV_NONE was
specified, so the signal number could be bogus.  If sigev_signo was an
unitialized value (as it often would be if SIGEV_NONE is used), then
it's hard to predict which signal will be sent.

Cc: stable@vger.kernel.org
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Richard Cochran 
Cc: Prarit Bhargava 
Cc: Sharvil Nanavati 
Signed-off-by: Richard Larocque 
Signed-off-by: John Stultz

alarmtimer: Return relative times in timer_gettime

2014-09-12T20:59:11+00:00

Returns the time remaining for an alarm timer, rather than the time at
which it is scheduled to expire.  If the timer has already expired or it
is not currently scheduled, the it_value's members are set to zero.

This new behavior matches that of the other posix-timers and the POSIX
specifications.

This is a change in user-visible behavior, and may break existing
applications.  Hopefully, few users rely on the old incorrect behavior.

Cc: stable@vger.kernel.org
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Richard Cochran 
Cc: Prarit Bhargava 
Cc: Sharvil Nanavati 
Signed-off-by: Richard Larocque 
[jstultz: minor style tweak]
Signed-off-by: John Stultz

Merge tag 'staging-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

2014-08-05T01:36:12+00:00

Pull staging driver updates from Greg KH:
 "Here's the big pull request for the staging driver tree for 3.17-rc1.

  Lots of things in here, over 2000 patches, but the best part is this:
   1480 files changed, 39070 insertions(+), 254659 deletions(-)

  Thanks to the great work of Kristina Martšenko, 14 different staging
  drivers have been removed from the tree as they were obsolete and no
  one was willing to work on cleaning them up.  Other than the driver
  removals, loads of cleanups are in here (comedi, lustre, etc.) as well
  as the usual IIO driver updates and additions.

  All of this has been in the linux-next tree for a while"

* tag 'staging-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (2199 commits)
  staging: comedi: addi_apci_1564: remove diagnostic interrupt support code
  staging: comedi: addi_apci_1564: add subdevice to check diagnostic status
  staging: wlan-ng: coding style problem fix
  staging: wlan-ng: fixing coding style problems
  staging: comedi: ii_pci20kc: request and ioremap memory
  staging: lustre: bitwise vs logical typo
  staging: dgnc: Remove unneeded dgnc_trace.c and dgnc_trace.h
  staging: dgnc: rephrase comment
  staging: comedi: ni_tio: remove some dead code
  staging: rtl8723au: Fix static symbol sparse warning
  staging: rtl8723au: usb_dvobj_init(): Remove unused variable 'pdev_desc'
  staging: rtl8723au: Do not duplicate kernel provided USB macros
  staging: rtl8723au: Remove never set struct pwrctrl_priv.bHWPowerdown
  staging: rtl8723au: Remove two never set variables
  staging: rtl8723au: RSSI_test is never set
  staging:r8190: coding style: Fixed checkpatch reported Error
  staging:r8180: coding style: Fixed too long lines
  staging:r8180: coding style: Fixed commenting style
  staging: lustre: ptlrpc: lproc_ptlrpc.c - fix dereferenceing user space buffer
  staging: lustre: ldlm: ldlm_resource.c - fix dereferenceing user space buffer
  ...

alarmtimer: Fix bug where relative alarm timers were treated as absolute

2014-07-08T08:49:36+00:00

Sharvil noticed with the posix timer_settime interface, using the
CLOCK_REALTIME_ALARM or CLOCK_BOOTTIME_ALARM clockid, if the users
tried to specify a relative time timer, it would incorrectly be
treated as absolute regardless of the state of the flags argument.

This patch corrects this, properly checking the absolute/relative flag,
as well as adds further error checking that no invalid flag bits are set.

Reported-by: Sharvil Nanavati 
Signed-off-by: John Stultz 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Prarit Bhargava 
Cc: Sharvil Nanavati 
Cc: stable  #3.0+
Link: http://lkml.kernel.org/r/1404767171-6902-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner