Eric Dumazet d0023a1448 timer: Write timer->flags atomically ...

lock_timer_base() cannot prevent the following :

CPU1 ( in __mod_timer()
timer->flags |= TIMER_MIGRATING;
spin_unlock(&base->lock);
base = new_base;
spin_lock(&base->lock);
// The next line clears TIMER_MIGRATING
timer->flags &= ~TIMER_BASEMASK;
                                  CPU2 (in lock_timer_base())
                                  see timer base is cpu0 base
                                  spin_lock_irqsave(&base->lock, *flags);
                                  if (timer->flags == tf)
                                       return base; // oops, wrong base
timer->flags |= base->cpu // too late

We must write timer->flags in one go, otherwise we can fool other cpus.

Fixes: bc7a34b8b9 ("timer: Reduce timer migration overhead if disabled")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jon Christopherson <jon@jons.org>
Cc: David Miller <davem@davemloft.net>
Cc: xen-devel@lists.xen.org
Cc: david.vrabel@citrix.com
Cc: Sander Eikelenboom <linux@eikelenboom.it>
Link: http://lkml.kernel.org/r/1439831928.32680.11.camel@edumazet-glaptop2.roam.corp.google.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>

2015-08-18 15:31:16 +02:00

..

alarmtimer.c

alarmtimer: Get rid of unused return value

2015-04-22 17:06:52 +02:00

clockevents.c

clockevents: Allow set-state callbacks to be optional

2015-07-07 10:44:45 +02:00

clocksource.c

clocksource: Use current logging style

2015-06-10 11:31:14 +02:00

hrtimer.c

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

2015-06-22 18:57:44 -07:00

itimer.c

…

jiffies.c

…

Kconfig

…

Makefile

time: Remove development rules from Kbuild/Makefile

2015-07-01 09:57:35 +02:00

ntp_internal.h

time: Prevent early expiry of hrtimers[CLOCK_REALTIME] at the leap second edge

2015-06-12 11:15:49 +02:00

ntp.c

ntp: Do leapsecond adjustment in adjtimex read path

2015-06-12 11:15:49 +02:00

posix-clock.c

…

posix-cpu-timers.c

sched, timer: Use the atomic task_cputime in thread_group_cputimer

2015-05-08 12:17:46 +02:00

posix-timers.c

hrtimer: Get rid of hrtimer_get_res()

2015-04-22 17:06:49 +02:00

sched_clock.c

…

test_udelay.c

…

tick-broadcast-hrtimer.c

tick: hrtimer-broadcast: Prevent endless restarting when broadcast device is unused

2015-05-05 15:34:21 +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

tick: Move the export of tick_broadcast_oneshot_control to the proper place

2015-07-14 12:01:04 +02:00

tick-internal.h

timer: Minimize nohz off overhead

2015-06-19 15:18:28 +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

timer: Minimize nohz off overhead

2015-06-19 15:18:28 +02:00

tick-sched.h

tick/broadcast: Make idle check independent from mode and config

2015-07-07 18:46:47 +02:00

time.c

time: Refactor usecs_to_jiffies

2015-06-10 11:31:13 +02:00

timeconst.bc

time: Move timeconst.h into include/generated

2015-05-19 15:13:45 +02:00

timeconv.c

…

timecounter.c

…

timekeeping_debug.c

…

timekeeping_internal.h

…

timekeeping.c

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2015-07-01 10:49:25 -07:00

timekeeping.h

hrtimer: Make offset update smarter

2015-04-22 17:06:49 +02:00

timer_list.c

timer: Reduce timer migration overhead if disabled

2015-06-19 15:18:28 +02:00

timer_stats.c

timer: Stats: Simplify the flags handling

2015-06-19 15:18:27 +02:00

timer.c

timer: Write timer->flags atomically

2015-08-18 15:31:16 +02:00