linux/kernel/time
Chang-An Chen 3f2552f7e9 timers/sched_clock: Prevent generic sched_clock wrap caused by tick_freeze()
tick_freeze() introduced by suspend-to-idle in commit 124cf9117c ("PM /
sleep: Make it possible to quiesce timers during suspend-to-idle") uses
timekeeping_suspend() instead of syscore_suspend() during
suspend-to-idle. As a consequence generic sched_clock will keep going
because sched_clock_suspend() and sched_clock_resume() are not invoked
during suspend-to-idle which can result in a generic sched_clock wrap.

On a ARM system with suspend-to-idle enabled, sched_clock is registered
as "56 bits at 13MHz, resolution 76ns, wraps every 4398046511101ns", which
means the real wrapping duration is 8796093022202ns.

[  134.551779] suspend-to-idle suspend (timekeeping_suspend())
[ 1204.912239] suspend-to-idle resume (timekeeping_resume())
......
[ 1206.912239] suspend-to-idle suspend (timekeeping_suspend())
[ 5880.502807] suspend-to-idle resume (timekeeping_resume())
......
[ 6000.403724] suspend-to-idle suspend (timekeeping_suspend())
[ 8035.753167] suspend-to-idle resume  (timekeeping_resume())
......
[ 8795.786684] (2)[321:charger_thread]......
[ 8795.788387] (2)[321:charger_thread]......
[    0.057226] (0)[0:swapper/0]......
[    0.061447] (2)[0:swapper/2]......

sched_clock was not stopped during suspend-to-idle, and sched_clock_poll
hrtimer was not expired because timekeeping_suspend() was invoked during
suspend-to-idle. It makes sched_clock wrap at kernel time 8796s.

To prevent this, invoke sched_clock_suspend() and sched_clock_resume() in
tick_freeze() together with timekeeping_suspend() and timekeeping_resume().

Fixes: 124cf9117c (PM / sleep: Make it possible to quiesce timers during suspend-to-idle)
Signed-off-by: Chang-An Chen <chang-an.chen@mediatek.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Corey Minyard <cminyard@mvista.com>
Cc: <linux-mediatek@lists.infradead.org>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Stanley Chu <stanley.chu@mediatek.com>
Cc: <kuohong.wang@mediatek.com>
Cc: <freddy.hsin@mediatek.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1553828349-8914-1-git-send-email-chang-an.chen@mediatek.com
2019-04-18 14:34:53 +02:00
..
alarmtimer.c alarmtimer: Return correct remaining time 2019-04-10 15:23:26 +02:00
clockevents.c hrtimers/tick/clockevents: Remove sloppy license references 2018-11-23 11:51:21 +01:00
clocksource.c time: Remove license boilerplate 2018-11-23 11:51:21 +01:00
hrtimer.c Merge branch 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-05 14:08:26 -08:00
itimer.c time: Remove useless filenames in top level comments 2018-11-23 11:51:20 +01:00
jiffies.c time/jiffies: Make refined_jiffies static 2019-03-22 13:38:26 +01:00
Kconfig time: Move CONTEXT_TRACKING to kernel/time/Kconfig 2019-01-15 11:16:41 +01:00
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 timex: use __kernel_timex internally 2019-02-07 00:13:27 +01:00
ntp.c timex: use __kernel_timex internally 2019-02-07 00:13:27 +01:00
posix-clock.c timex: use __kernel_timex internally 2019-02-07 00:13:27 +01:00
posix-cpu-timers.c posix-cpu-timers: Remove private interval storage 2019-01-15 16:36:13 +01:00
posix-stubs.c y2038: syscalls: rename y2038 compat syscalls 2019-02-07 00:13:27 +01:00
posix-timers.c y2038: syscalls: rename y2038 compat syscalls 2019-02-07 00:13:27 +01:00
posix-timers.h timex: use __kernel_timex internally 2019-02-07 00:13:27 +01:00
sched_clock.c timers/sched_clock: Prevent generic sched_clock wrap caused by tick_freeze() 2019-04-18 14:34:53 +02:00
test_udelay.c time/debug: Remove license boilerplate 2018-11-23 11:51:21 +01:00
tick-broadcast-hrtimer.c time: Remove useless filenames in top level comments 2018-11-23 11:51:20 +01:00
tick-broadcast.c timers: Mark expected switch fall-throughs 2019-01-29 20:08:42 +01:00
tick-common.c timers/sched_clock: Prevent generic sched_clock wrap caused by tick_freeze() 2019-04-18 14:34:53 +02:00
tick-internal.h Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME 2018-04-26 14:53:32 +02:00
tick-oneshot.c hrtimers/tick/clockevents: Remove sloppy license references 2018-11-23 11:51:21 +01:00
tick-sched.c hrtimers/tick/clockevents: Remove sloppy license references 2018-11-23 11:51:21 +01:00
tick-sched.h nohz: Gather tick_sched booleans under a common flag field 2018-04-09 11:54:57 +02:00
time.c y2038: rename old time and utime syscalls 2019-02-07 00:13:28 +01:00
timeconst.bc time: Add SPDX license identifiers 2018-11-23 11:51:20 +01:00
timeconv.c time: Add SPDX license identifiers 2018-11-23 11:51:20 +01:00
timecounter.c time: Remove license boilerplate 2018-11-23 11:51:21 +01:00
timekeeping_debug.c timekeeping/debug: No need to check return value of debugfs_create functions 2019-01-29 20:08:41 +01:00
timekeeping_internal.h timekeeping/ntp: Constify some function arguments 2018-07-19 17:08:05 -07:00
timekeeping.c timex: use __kernel_timex internally 2019-02-07 00:13:27 +01:00
timekeeping.h timers/sched_clock: Prevent generic sched_clock wrap caused by tick_freeze() 2019-04-18 14:34:53 +02:00
timer_list.c hrtimers/tick/clockevents: Remove sloppy license references 2018-11-23 11:51:21 +01:00
timer.c Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-05 14:49:11 -08:00