commit 27727df240 upstream.
When I added some extra sanity checking in timekeeping_get_ns() under
CONFIG_DEBUG_TIMEKEEPING, I missed that the NMI safe __ktime_get_fast_ns()
method was using timekeeping_get_ns().
Thus the locking added to the debug checks broke the NMI-safety of
__ktime_get_fast_ns().
This patch open-codes the timekeeping_get_ns() logic for
__ktime_get_fast_ns(), so can avoid any deadlocks in NMI.
Fixes: 4ca22c2648 "timekeeping: Add warnings when overflows or underflows are observed"
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1471993702-29148-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a4f8f6667f upstream.
It was reported that hibernation could fail on the 2nd attempt, where the
system hangs at hibernate() -> syscore_resume() -> i8237A_resume() ->
claim_dma_lock(), because the lock has already been taken.
However there is actually no other process would like to grab this lock on
that problematic platform.
Further investigation showed that the problem is triggered by setting
/sys/power/pm_trace to 1 before the 1st hibernation.
Since once pm_trace is enabled, the rtc becomes unmeaningful after suspend,
and meanwhile some BIOSes would like to adjust the 'invalid' RTC (e.g, smaller
than 1970) to the release date of that motherboard during POST stage, thus
after resumed, it may seem that the system had a significant long sleep time
which is a completely meaningless value.
Then in timekeeping_resume -> tk_debug_account_sleep_time, if the bit31 of the
sleep time happened to be set to 1, fls() returns 32 and we add 1 to
sleep_time_bin[32], which causes an out of bounds array access and therefor
memory being overwritten.
As depicted by System.map:
0xffffffff81c9d080 b sleep_time_bin
0xffffffff81c9d100 B dma_spin_lock
the dma_spin_lock.val is set to 1, which caused this problem.
This patch adds a sanity check in tk_debug_account_sleep_time()
to ensure we don't index past the sleep_time_bin array.
[jstultz: Problem diagnosed and original patch by Chen Yu, I've solved the
issue slightly differently, but borrowed his excelent explanation of the
issue here.]
Fixes: 5c83545f24 "power: Add option to log time spent in suspend"
Reported-by: Janek Kozicki <cosurgi@gmail.com>
Reported-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: linux-pm@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xunlei Pang <xpang@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Zhang Rui <rui.zhang@intel.com>
Link: http://lkml.kernel.org/r/1471993702-29148-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 37cf4dc337 ]
For adjtimex()'s ADJ_SETOFFSET, make sure the tv_usec value is
sane. We might multiply them later which can cause an overflow
and undefined behavior.
This patch introduces new helper functions to simplify the
checking code and adds comments to clarify
Orginally this patch was by Sasha Levin, but I've basically
rewritten it, so he should get credit for finding the issue
and I should get the blame for any mistakes made since.
Also, credit to Richard Cochran for the phrasing used in the
comment for what is considered valid here.
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2c13ce8f6b upstream.
Variable "now" seems to be genuinely used unintialized
if branch
if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
is not taken and branch
if (unlikely(sighand == NULL)) {
is taken. In this case the process has been reaped and the timer is marked as
disarmed anyway. So none of the postprocessing of the sample is
required. Return right away.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Link: http://lkml.kernel.org/r/20160707223911.GA26483@p183.telecom.by
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 35a4933a89 upstream.
1e75fa8 "time: Condense timekeeper.xtime into xtime_sec" replaced a call to
clocksource_cyc2ns() from timekeeping_get_ns() with an open-coded version
of the same logic to avoid keeping a semi-redundant struct timespec
in struct timekeeper.
However, the commit also introduced a subtle semantic change - where
clocksource_cyc2ns() uses purely unsigned math, the new version introduces
a signed temporary, meaning that if (delta * tk->mult) has a 63-bit
overflow the following shift will still give a negative result. The
choice of 'maxsec' in __clocksource_updatefreq_scale() means this will
generally happen if there's a ~10 minute pause in examining the
clocksource.
This can be triggered on a powerpc KVM guest by stopping it from qemu for
a bit over 10 minutes. After resuming time has jumped backwards several
minutes causing numerous problems (jiffies does not advance, msleep()s can
be extended by minutes..). It doesn't happen on x86 KVM guests, because
the guest TSC is effectively frozen while the guest is stopped, which is
not the case for the powerpc timebase.
Obviously an unsigned (64 bit) overflow will only take twice as long as a
signed, 63-bit overflow. I don't know the time code well enough to know
if that will still cause incorrect calculations, or if a 64-bit overflow
is avoided elsewhere.
Still, an incorrect forwards clock adjustment will cause less trouble than
time going backwards. So, this patch removes the potential for
intermediate signed overflow.
Suggested-by: Laurent Vivier <lvivier@redhat.com>
Tested-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1b9f23727a upstream.
The posix_clock_poll function is supposed to return a bit mask of
POLLxxx values. However, in case the hardware has disappeared (due to
hot plugging for example) this code returns -ENODEV in a futile
attempt to throw an error at the file descriptor level. The kernel's
file_operations interface does not accept such error codes from the
poll method. Instead, this function aught to return POLLERR.
The value -ENODEV does, in fact, contain the POLLERR bit (and almost
all the other POLLxxx bits as well), but only by chance. This patch
fixes code to return a proper bit mask.
Credit goes to Markus Elfring for pointing out the suspicious
signed/unsigned mismatch.
Reported-by: Markus Elfring <elfring@users.sourceforge.net>
igned-off-by: Richard Cochran <richardcochran@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Link: http://lkml.kernel.org/r/1450819198-17420-1-git-send-email-richardcochran@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 203cbf77de upstream.
If CONFIG_TIME_LOW_RES is enabled we add a jiffie to the relative timeout to
prevent short sleeps, but we do not account for that in interfaces which
retrieve the remaining time.
Helge observed that timerfd can return a remaining time larger than the
relative timeout. That's not expected and breaks userland test programs.
Store the information that the timer was armed relative and provide functions
to adjust the remaining time. To avoid bloating the hrtimer struct make state
a u8, which as a bonus results in better code on x86 at least.
Reported-and-tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: dhowells@redhat.com
Link: http://lkml.kernel.org/r/20160114164159.273328486@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull irq and timer fixes from Thomas Gleixner:
- An irq regression fix to restore the wakeup behaviour of chained
interrupts.
- A timer fix for a long standing race versus timers scheduled on a
target cpu which got exposed by recent changes in the workqueue
implementation.
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq/PM: Restore system wake up from chained interrupts
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timers: Use proper base migration in add_timer_on()
Regardless of the previous CPU a timer was on, add_timer_on()
currently simply sets timer->flags to the new CPU. As the caller must
be seeing the timer as idle, this is locally fine, but the timer
leaving the old base while unlocked can lead to race conditions as
follows.
Let's say timer was on cpu 0.
cpu 0 cpu 1
-----------------------------------------------------------------------------
del_timer(timer) succeeds
del_timer(timer)
lock_timer_base(timer) locks cpu_0_base
add_timer_on(timer, 1)
spin_lock(&cpu_1_base->lock)
timer->flags set to cpu_1_base
operates on @timer operates on @timer
This triggered with mod_delayed_work_on() which contains
"if (del_timer()) add_timer_on()" sequence eventually leading to the
following oops.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff810ca6e9>] detach_if_pending+0x69/0x1a0
...
Workqueue: wqthrash wqthrash_workfunc [wqthrash]
task: ffff8800172ca680 ti: ffff8800172d0000 task.ti: ffff8800172d0000
RIP: 0010:[<ffffffff810ca6e9>] [<ffffffff810ca6e9>] detach_if_pending+0x69/0x1a0
...
Call Trace:
[<ffffffff810cb0b4>] del_timer+0x44/0x60
[<ffffffff8106e836>] try_to_grab_pending+0xb6/0x160
[<ffffffff8106e913>] mod_delayed_work_on+0x33/0x80
[<ffffffffa0000081>] wqthrash_workfunc+0x61/0x90 [wqthrash]
[<ffffffff8106dba8>] process_one_work+0x1e8/0x650
[<ffffffff8106e05e>] worker_thread+0x4e/0x450
[<ffffffff810746af>] kthread+0xef/0x110
[<ffffffff8185980f>] ret_from_fork+0x3f/0x70
Fix it by updating add_timer_on() to perform proper migration as
__mod_timer() does.
Reported-and-tested-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Chris Worley <chris.worley@primarydata.com>
Cc: bfields@fieldses.org
Cc: Michael Skralivetsky <michael.skralivetsky@primarydata.com>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: kernel-team@fb.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20151029103113.2f893924@tlielax.poochiereds.net
Link: http://lkml.kernel.org/r/20151104171533.GI5749@mtj.duckdns.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull timer updates from Thomas Gleixner:
"The timer departement provides:
- More y2038 work in the area of ntp and pps.
- Optimization of posix cpu timers
- New time related selftests
- Some new clocksource drivers
- The usual pile of fixes, cleanups and improvements"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
timeconst: Update path in comment
timers/x86/hpet: Type adjustments
clocksource/drivers/armada-370-xp: Implement ARM delay timer
clocksource/drivers/tango_xtal: Add new timer for Tango SoCs
clocksource/drivers/imx: Allow timer irq affinity change
clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr()
clocksource/drivers/h8300_*: Remove unneeded memset()s
clocksource/drivers/sh_cmt: Remove unneeded memset() in sh_cmt_setup()
clocksource/drivers/em_sti: Remove unneeded memset()s
clocksource/drivers/mediatek: Use GPT as sched clock source
clockevents/drivers/mtk: Fix spurious interrupt leading to crash
posix_cpu_timer: Reduce unnecessary sighand lock contention
posix_cpu_timer: Convert cputimer->running to bool
posix_cpu_timer: Check thread timers only when there are active thread timers
posix_cpu_timer: Optimize fastpath_timer_check()
timers, kselftest: Add 'adjtick' test to validate adjtimex() tick adjustments
timers: Use __fls in apply_slack()
clocksource: Remove return statement from void functions
net: sfc: avoid using timespec
ntp/pps: use y2038 safe types in pps_event_time
...
timekeeping_init() can set the wall time offset, so we need to
increment the clock_was_set_seq counter. That way hrtimers will pick
up the early offset immediately. Otherwise on a machine which does not
set wall time later in the boot process the hrtimer offset is stale at
0 and wall time timers are going to expire with a delay of 45 years.
Fixes: 868a3e915f "hrtimer: Make offset update smarter"
Reported-and-tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Stefan Liebler <stli@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
It was found while running a database workload on large systems that
significant time was spent trying to acquire the sighand lock.
The issue was that whenever an itimer expired, many threads ended up
simultaneously trying to send the signal. Most of the time, nothing
happened after acquiring the sighand lock because another thread
had just already sent the signal and updated the "next expire" time.
The fastpath_timer_check() didn't help much since the "next expire"
time was updated after the threads exit fastpath_timer_check().
This patch addresses this by having the thread_group_cputimer structure
maintain a boolean to signify when a thread in the group is already
checking for process wide timers, and adds extra logic in the fastpath
to check the boolean.
Signed-off-by: Jason Low <jason.low2@hp.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: George Spelvin <linux@horizon.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: hideaki.kimura@hpe.com
Cc: terry.rudd@hpe.com
Cc: scott.norton@hpe.com
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1444849677-29330-5-git-send-email-jason.low2@hp.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
In apply_slack(), find_last_bit() is applied to a bitmask consisting
of precisely BITS_PER_LONG bits. Since mask is non-zero, we might as
well eliminate the function call and use __fls() directly. On x86_64,
this shaves 23 bytes of the only caller, mod_timer().
This also gets rid of Coverity CID 1192106, but that is a false
positive: Coverity is not aware that mask != 0 implies that
find_last_bit will not return BITS_PER_LONG.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1443771931-6284-1-git-send-email-linux@rasmusvillemoes.dk
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The sync_cmos_clock has one use of struct timespec, which we want to
eventually replace with timespec64 or similar in the kernel. There
is no way this one can overflow, but the conversion to timespec64
is trivial and has no other dependencies.
Acked-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
There is exactly one caller of getnstime_raw_and_real in the kernel,
which is the pps_get_ts function. This changes the caller and
the implementation to work on timespec64 types rather than timespec,
to avoid the time_t overflow on 32-bit architectures.
For consistency with the other new functions (ktime_get_seconds,
ktime_get_real_*, ...), I'm renaming the function to
ktime_get_raw_and_real_ts64.
We still need to convert from the internal 64-bit type to 32 bit
types in the caller, but this conversion is now pushed out from
getnstime_raw_and_real to pps_get_ts. A follow-up patch changes
the remaining pps code to completely avoid the conversion.
Acked-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
There is only one user of the hardpps function in the kernel, so
it makes sense to atomically change it over to using 64-bit
timestamps for y2038 safety. In the hardpps implementation,
we also need to change the pps_normtime structure, which is
similar to struct timespec and also requires a 64-bit
seconds portion.
This introduces two temporary variables in pps_kc_event() to
do the conversion, they will be removed again in the next step,
which seemed preferable to having a larger patch changing it
all at the same time.
Acked-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Pull timer fixes from Ingo Molnar:
"A fix for an abs()/abs64() bug that caused too slow NTP convergence on
32-bit kernels, plus a removal of an obsolete clockevents driver
facility after all users got converted during the merge window"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clockevents: Remove unused set_mode() callback
time: Fix timekeeping_freqadjust()'s incorrect use of abs() instead of abs64()
The internal clocksteering done for fine-grained error
correction uses a logarithmic approximation, so any time
adjtimex() adjusts the clock steering, timekeeping_freqadjust()
quickly approximates the correct clock frequency over a series
of ticks.
Unfortunately, the logic in timekeeping_freqadjust(), introduced
in commit:
dc491596f6 ("timekeeping: Rework frequency adjustments to work better w/ nohz")
used the abs() function with a s64 error value to calculate the
size of the approximated adjustment to be made.
Per include/linux/kernel.h:
"abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()".
Thus on 32-bit platforms, this resulted in the clocksteering to
take a quite dampended random walk trying to converge on the
proper frequency, which caused the adjustments to be made much
slower then intended (most easily observed when large
adjustments are made).
This patch fixes the issue by using abs64() instead.
Reported-by: Nuno Gonçalves <nunojpg@gmail.com>
Tested-by: Nuno Goncalves <nunojpg@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: <stable@vger.kernel.org> # v3.17+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1441840051-20244-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull timer updates from Thomas Gleixner:
"Rather large, but nothing exiting:
- new range check for settimeofday() to prevent that boot time
becomes negative.
- fix for file time rounding
- a few simplifications of the hrtimer code
- fix for the proc/timerlist code so the output of clock realtime
timers is accurate
- more y2038 work
- tree wide conversion of clockevent drivers to the new callbacks"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (88 commits)
hrtimer: Handle failure of tick_init_highres() gracefully
hrtimer: Unconfuse switch_hrtimer_base() a bit
hrtimer: Simplify get_target_base() by returning current base
hrtimer: Drop return code of hrtimer_switch_to_hres()
time: Introduce timespec64_to_jiffies()/jiffies_to_timespec64()
time: Introduce current_kernel_time64()
time: Introduce struct itimerspec64
time: Add the common weak version of update_persistent_clock()
time: Always make sure wall_to_monotonic isn't positive
time: Fix nanosecond file time rounding in timespec_trunc()
timer_list: Add the base offset so remaining nsecs are accurate for non monotonic timers
cris/time: Migrate to new 'set-state' interface
kernel: broadcast-hrtimer: Migrate to new 'set-state' interface
xtensa/time: Migrate to new 'set-state' interface
unicore/time: Migrate to new 'set-state' interface
um/time: Migrate to new 'set-state' interface
sparc/time: Migrate to new 'set-state' interface
sh/localtimer: Migrate to new 'set-state' interface
score/time: Migrate to new 'set-state' interface
s390/time: Migrate to new 'set-state' interface
...
Pull NOHZ updates from Ingo Molnar:
"The main changes, mostly written by Frederic Weisbecker, include:
- Fix some jiffies based cputime assumptions. (No real harm because
the concerned code isn't used by full dynticks.)
- Simplify jiffies <-> usecs conversions. Remove dead code.
- Remove early hacks on nohz full code that avoided messing up idle
nohz internals. Now nohz integrates well full and idle and such
hack have become needless.
- Restart nohz full tick from irq exit. (A simplification and a
preparation for future optimization on scheduler kick to nohz
full)
- Code cleanups.
- Tile driver isolation enhancement on top of nohz. (Chris Metcalf)"
* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
nohz: Remove useless argument on tick_nohz_task_switch()
nohz: Move tick_nohz_restart_sched_tick() above its users
nohz: Restart nohz full tick from irq exit
nohz: Remove idle task special case
nohz: Prevent tilegx network driver interrupts
alpha: Fix jiffies based cputime assumption
apm32: Fix cputime == jiffies assumption
jiffies: Remove HZ > USEC_PER_SEC special case
Pull RCU updates from Ingo Molnar:
"The main RCU changes in this cycle are:
- the combination of tree geometry-initialization simplifications and
OS-jitter-reduction changes to expedited grace periods. These two
are stacked due to the large number of conflicts that would
otherwise result.
- privatize smp_mb__after_unlock_lock().
This commit moves the definition of smp_mb__after_unlock_lock() to
kernel/rcu/tree.h, in recognition of the fact that RCU is the only
thing using this, that nothing else is likely to use it, and that
it is likely to go away completely.
- documentation updates.
- torture-test updates.
- misc fixes"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
rcu,locking: Privatize smp_mb__after_unlock_lock()
rcu: Silence lockdep false positive for expedited grace periods
rcu: Don't disable CPU hotplug during OOM notifiers
scripts: Make checkpatch.pl warn on expedited RCU grace periods
rcu: Update MAINTAINERS entry
rcu: Clarify CONFIG_RCU_EQS_DEBUG help text
rcu: Fix backwards RCU_LOCKDEP_WARN() in synchronize_rcu_tasks()
rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN()
rcu: Make rcu_is_watching() really notrace
cpu: Wait for RCU grace periods concurrently
rcu: Create a synchronize_rcu_mult()
rcu: Fix obsolete priority-boosting comment
rcu: Use WRITE_ONCE in RCU_INIT_POINTER
rcu: Hide RCU_NOCB_CPU behind RCU_EXPERT
rcu: Add RCU-sched flavors of get-state and cond-sync
rcu: Add fastpath bypassing funnel locking
rcu: Rename RCU_GP_DONE_FQS to RCU_GP_DOING_FQS
rcu: Pull out wait_event*() condition into helper function
documentation: Describe new expedited stall warnings
rcu: Add stall warnings to synchronize_sched_expedited()
...
Commit 75e3b37d05 ("hrtimer: Drop return code of hrtimer_switch_to_hres()")
drops the return code of hrtimer_switch_to_hres(). While doing so, it also
drops the return statement itself on failure. This may cause a system hang.
Seen when running arm:multi_v7_defconfig in qemu with devicetree file
vexpress-v2p-ca9.
Fixes: 75e3b37d05 ("hrtimer: Drop return code of hrtimer_switch_to_hres()")
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: http://lkml.kernel.org/r/1440231047-16256-1-git-send-email-linux@roeck-us.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The variable called "this_base" is confusing because its name suggests
it's of "struct hrtimer_clock_base" type, along with "base" and "new_base"
which doesn't help understanding this complicated function.
Make its name clearer and fix the misleading comment while at it.
[ tglx: Fixed the comment for real ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1439907509-9553-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The conversion between struct timespec and jiffies is not year 2038
safe on 32bit systems. Introduce timespec64_to_jiffies() and
jiffies_to_timespec64() functions which use struct timespec64 to
make it ready for 2038 issue.
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The weak update_persistent_clock64() calls update_persistent_clock(),
if the architecture defines an update_persistent_clock64() to replace
and remove its update_persistent_clock() version, when building the
kernel the linker will throw an undefined symbol error, that is, any
arch that switches to update_persistent_clock64() will have this issue.
To solve the issue, we add the common weak update_persistent_clock().
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
