linux/kernel/time
Thomas Gleixner 4da9152a43 timers: Lock base for same bucket optimization
Linus stumbled over the unlocked modification of the timer expiry value in
mod_timer() which is an optimization for timers which stay in the same
bucket - due to the bucket granularity - despite their expiry time getting
updated.

The optimization itself still makes sense even if we take the lock, because
in case that the bucket stays the same, we avoid the pointless
queue/enqueue dance.

Make the check and the modification of timer->expires protected by the base
lock and shuffle the remaining code around so we can keep the lock held
when we actually have to requeue the timer to a different bucket.

Fixes: f00c0afdfa ("timers: Implement optimization for same expiry time in mod_timer()")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1610241711220.4983@nanos
Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
2016-10-25 16:27:39 +02:00
..
alarmtimer.c alarmtimer: Remove unused but set variable 2016-10-17 11:59:37 +02:00
clockevents.c clockevents: Make clockevents_subsys static 2016-07-19 10:48:06 +02:00
clocksource.c clocksource: Defer override invalidation unless clock is unstable 2016-08-31 14:43:33 -07:00
hrtimer.c time: Avoid undefined behaviour in ktime_add_safe() 2016-08-31 14:43:36 -07:00
itimer.c itimers: Handle relative timers with CONFIG_TIME_LOW_RES proper 2016-01-17 11:13:55 +01:00
jiffies.c jiffies: Use CLOCKSOURCE_MASK instead of constant 2016-02-27 08:55:31 +01:00
Kconfig rcu: Drop RCU_USER_QS in favor of NO_HZ_FULL 2015-07-06 13:52:18 -07:00
Makefile time: Remove development rules from Kbuild/Makefile 2015-07-01 09:57:35 +02:00
ntp_internal.h ntp: Fix second_overflow's input parameter type to be 64bits 2015-12-16 16:50:56 -08:00
ntp.c ntp: Fix ADJ_SETOFFSET being used w/ ADJ_NANO 2016-01-22 12:01:42 +01:00
posix-clock.c posix-clock: Fix return code on the poll method's error path 2015-12-29 11:33:06 +01:00
posix-cpu-timers.c posix_cpu_timer: Exit early when process has been reaped 2016-07-11 17:20:12 +02:00
posix-timers.c posix-timers: Handle relative timers with CONFIG_TIME_LOW_RES proper 2016-01-17 11:13:55 +01:00
sched_clock.c timers, sched/clock: Clean up the code a bit 2015-03-27 08:34:01 +01:00
test_udelay.c time: Avoid timespec in udelay_test 2016-06-20 12:47:26 -07:00
tick-broadcast-hrtimer.c tick/broadcast-hrtimer: Set name of the ce_broadcast_hrtimer 2016-07-05 17:02:19 +02:00
tick-broadcast.c tick: Move the export of tick_broadcast_oneshot_control to the proper place 2015-07-14 12:01:04 +02:00
tick-common.c clockevents: Remove unused set_mode() callback 2015-09-14 11:00:55 +02:00
tick-internal.h timers: Forward the wheel clock whenever possible 2016-07-07 10:35:11 +02:00
tick-oneshot.c clockevents: Provide functions to set and get the state 2015-06-02 14:40:47 +02:00
tick-sched.c tick/nohz: Prevent stopping the tick on an offline CPU 2016-09-13 17:53:52 +02:00
tick-sched.h timers/nohz: Convert tick dependency mask to atomic_t 2016-03-29 11:52:11 +02:00
time.c time: Avoid undefined behaviour in timespec64_add_safe() 2016-08-31 14:43:35 -07:00
timeconst.bc timeconst: Update path in comment 2015-10-26 10:06:06 +09:00
timeconv.c time: Add time64_to_tm() 2016-06-20 12:47:15 -07:00
timecounter.c timecounter: keep track of accumulated fractional nanoseconds 2014-12-30 18:29:27 -05:00
timekeeping_debug.c timekeeping: Prints the amounts of time spent during suspend 2016-08-31 14:43:34 -07:00
timekeeping_internal.h clocksource: Make clocksource validation work for all clocksources 2015-12-19 15:59:57 +01:00
timekeeping.c timekeeping: Fix __ktime_get_fast_ns() regression 2016-10-05 15:44:46 +02:00
timekeeping.h hrtimer: Make offset update smarter 2015-04-22 17:06:49 +02:00
timer_list.c hrtimer: Handle remaining time proper for TIME_LOW_RES 2016-01-17 11:13:55 +01:00
timer_stats.c timer: Avoid using timespec 2016-06-20 12:47:33 -07:00
timer.c timers: Lock base for same bucket optimization 2016-10-25 16:27:39 +02:00