Peter Zijlstra e2c631ba75 clocksource: Revert "Remove kthread" ...

I turns out that the silly spawn kthread from worker was actually needed.

clocksource_watchdog_kthread() cannot be called directly from
clocksource_watchdog_work(), because clocksource_select() calls
timekeeping_notify() which uses stop_machine(). One cannot use
stop_machine() from a workqueue() due lock inversions wrt CPU hotplug.

Revert the patch but add a comment that explain why we jump through such
apparently silly hoops.

Fixes: 7197e77abc ("clocksource: Remove kthread")
Reported-by: Siegfried Metz <frame@mailbox.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Tested-by: Kevin Shanahan <kevin@shanahan.id.au>
Tested-by: viktor_jaegerskuepper@freenet.de
Tested-by: Siegfried Metz <frame@mailbox.org>
Cc: rafael.j.wysocki@intel.com
Cc: len.brown@intel.com
Cc: diego.viola@gmail.com
Cc: rui.zhang@intel.com
Cc: bjorn.andersson@linaro.org
Link: https://lkml.kernel.org/r/20180905084158.GR24124@hirez.programming.kicks-ass.net

2018-09-06 23:38:35 +02:00

..

alarmtimer.c

alarmtimer: Prevent overflow for relative nanosleep

2018-07-02 11:33:26 +02:00

clockevents.c

clockevents: Warn if cpu_all_mask is used as cpumask

2018-08-02 14:55:53 +02:00

clocksource.c

clocksource: Revert "Remove kthread"

2018-09-06 23:38:35 +02:00

hrtimer.c

Merge branch 'fortglx/4.19/time' of https://git.linaro.org/people/john.stultz/linux into timers/core

2018-07-12 22:19:58 +02:00

itimer.c

pid: Implement PIDTYPE_TGID

2018-07-21 10:43:12 -05:00

jiffies.c

jiffies: Revert bogus conversion of NSEC_PER_SEC to TICK_NSEC

2017-03-07 11:03:28 +01:00

Kconfig

sched/isolation: Eliminate NO_HZ_FULL_ALL

2018-02-15 15:40:37 -08:00

Makefile

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02 11:10:55 +01:00

ntp_internal.h

timekeeping/ntp: Constify some function arguments

2018-07-19 17:08:05 -07:00

ntp.c

timekeeping/ntp: Constify some function arguments

2018-07-19 17:08:05 -07:00

posix-clock.c

vfs: do bulk POLL* -> EPOLL* replacement

2018-02-11 14:34:03 -08:00

posix-cpu-timers.c

Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2018-08-21 13:47:29 -07:00

posix-stubs.c

posix-timers: Use new ktime_get_*_ts64() helpers

2018-06-19 09:56:27 +02:00

posix-timers.c

Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2018-08-21 13:47:29 -07:00

posix-timers.h

posix-timers: Make forward callback return s64

2018-07-02 11:33:25 +02:00

sched_clock.c

sched/clock: Move sched clock initialization and merge with generic clock

2018-07-20 00:02:43 +02:00

test_udelay.c

time: Avoid timespec in udelay_test

2016-06-20 12:47:26 -07:00

tick-broadcast-hrtimer.c

tick/broadcast-hrtimer: Use cpu_possible_mask for ce_broadcast_hrtimer

2018-08-02 14:55:52 +02:00

tick-broadcast.c

tick/broadcast: Use for_each_cpu() specially on UP kernels

2018-05-15 22:45:54 +02:00

tick-common.c

Revert "tick: Prefer a lower rating device only if it's CPU local device"

2018-07-10 22:12:47 +02:00

tick-internal.h

Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME

2018-04-26 14:53:32 +02:00

tick-oneshot.c

clockevents: Fix kernel messages split across multiple lines

2018-04-17 17:18:04 +02:00

tick-sched.c

nohz: Fix local_timer_softirq_pending()

2018-07-31 22:08:44 +02:00

tick-sched.h

nohz: Gather tick_sched booleans under a common flag field

2018-04-09 11:54:57 +02:00

time.c

Merge branch 'fortglx/4.19/time' of https://git.linaro.org/people/john.stultz/linux into timers/core

2018-07-12 22:19:58 +02:00

timeconst.bc

time: Introduce jiffies64_to_nsecs()

2017-02-01 09:13:45 +01:00

timeconv.c

time: Add time64_to_tm()

2016-06-20 12:47:15 -07:00

timecounter.c

clocksource: Use a plain u64 instead of cycle_t

2016-12-25 11:04:12 +01:00

timekeeping_debug.c

timekeeping/ntp: Constify some function arguments

2018-07-19 17:08:05 -07:00

timekeeping_internal.h

timekeeping/ntp: Constify some function arguments

2018-07-19 17:08:05 -07:00

timekeeping.c

Merge branch 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-08-13 18:28:19 -07:00

timekeeping.h

Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME

2018-04-26 14:53:32 +02:00

timer_list.c

Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-06-04 20:27:54 -07:00

timer.c

timers: Clear timer_base::must_forward_clk with timer_base::lock held

2018-08-02 12:52:38 +02:00