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John Stultz bb6ed34f2a hrtimer: Update hrtimer base offsets each hrtimer_interrupt 
This is a backport of 5baefd6d84

The update of the hrtimer base offsets on all cpus cannot be made
atomically from the timekeeper.lock held and interrupt disabled region
as smp function calls are not allowed there.

clock_was_set(), which enforces the update on all cpus, is called
either from preemptible process context in case of do_settimeofday()
or from the softirq context when the offset modification happened in
the timer interrupt itself due to a leap second.

In both cases there is a race window for an hrtimer interrupt between
dropping timekeeper lock, enabling interrupts and clock_was_set()
issuing the updates. Any interrupt which arrives in that window will
see the new time but operate on stale offsets.

So we need to make sure that an hrtimer interrupt always sees a
consistent state of time and offsets.

ktime_get_update_offsets() allows us to get the current monotonic time
and update the per cpu hrtimer base offsets from hrtimer_interrupt()
to capture a consistent state of monotonic time and the offsets. The
function replaces the existing ktime_get() calls in hrtimer_interrupt().

The overhead of the new function vs. ktime_get() is minimal as it just
adds two store operations.

This ensures that any changes to realtime or boottime offsets are
noticed and stored into the per-cpu hrtimer base structures, prior to
any hrtimer expiration and guarantees that timers are not expired early.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1341960205-56738-8-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-19 08:58:46 -07:00
..
debug kgdb,debug_core: pass the breakpoint struct instead of address and memory 2012-04-13 08:14:07 -07:00
events perf: Fix software event overflow 2011-08-04 21:58:35 -07:00
gcov gcov: disable CONFIG_CONSTRUCTORS when not needed by CONFIG_GCOV_KERNEL 2011-06-15 20:04:01 -07:00
irq genirq: Adjust irq thread affinity on IRQ_SET_MASK_OK_NOCOPY return value 2012-04-13 08:14:06 -07:00
power PM / Hibernate: Enable usermodehelpers in hibernate() error path 2012-04-02 09:27:18 -07:00
time timekeeping: Provide hrtimer update function 2012-07-19 08:58:46 -07:00
trace tracing: change CPU ring buffer state from tracing_cpumask 2012-07-16 08:47:51 -07:00
.gitignore
acct.c
async.c
audit.c netlink: kill loginuid/sessionid/sid members from struct netlink_skb_parms 2011-03-03 10:55:40 -08:00
audit.h audit: make functions static 2010-10-30 01:42:19 -04:00
audit_tree.c Fix common misspellings 2011-03-31 11:26:23 -03:00
audit_watch.c kill path_lookup() 2011-03-14 09:15:23 -04:00
auditfilter.c netlink: kill loginuid/sessionid/sid members from struct netlink_skb_parms 2011-03-03 10:55:40 -08:00
auditsc.c audit: acquire creds selectively to reduce atomic op overhead 2011-04-27 15:11:03 +02:00
backtracetest.c
bounds.c memcg: remove direct page_cgroup-to-page pointer 2011-03-23 19:46:28 -07:00
capability.c Merge branch 'master' into next 2011-05-19 18:51:57 +10:00
cgroup.c cgroup: fix to allow mounting a hierarchy by name 2012-01-12 11:35:08 -08:00
cgroup_freezer.c cgroup_freezer: fix freezing groups with stopped tasks 2011-12-09 08:52:27 -08:00
compat.c compat: Fix RT signal mask corruption via sigprocmask 2012-05-21 09:40:04 -07:00
configs.c
cpu.c PM / Sleep: Fix race between CPU hotplug and freezer 2012-01-12 11:35:46 -08:00
cpuset.c cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowed 2011-05-28 17:02:57 +02:00
crash_dump.c crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn 2011-03-23 19:47:19 -07:00
cred.c cred: copy_process() should clear child->replacement_session_keyring 2012-04-13 08:14:08 -07:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c ptrace: partially fix the do_wait(WEXITED) vs EXIT_DEAD->EXIT_ZOMBIE race 2012-01-06 14:14:14 -08:00
extable.c extable, core_kernel_data(): Make sure all archs define _sdata 2011-05-20 08:56:56 +02:00
fork.c namespaces, pid_ns: fix leakage on fork() failure 2012-05-21 09:40:01 -07:00
freezer.c Freezer: Use SMP barriers 2011-05-17 23:19:17 +02:00
futex.c futex: Do not leak robust list to unprivileged process 2012-04-22 16:21:45 -07:00
futex_compat.c futex: Do not leak robust list to unprivileged process 2012-04-22 16:21:45 -07:00
groups.c userns: user namespaces: convert several capable() calls 2011-03-23 19:47:08 -07:00
hrtimer.c hrtimer: Update hrtimer base offsets each hrtimer_interrupt 2012-07-19 08:58:46 -07:00
hung_task.c hung_task: fix false positive during vfork 2012-01-06 14:14:13 -08:00
irq_work.c irq_work: Use per cpu atomics instead of regular atomics 2010-12-18 15:54:48 +01:00
itimer.c
jump_label.c jump_label: jump_label_inc may return before the code is patched 2011-12-09 08:52:50 -08:00
kallsyms.c Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-03-25 17:52:22 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks arch:Kconfig.locks Remove unused config option. 2011-04-10 17:01:05 +02:00
Kconfig.preempt
kexec.c PM: Remove sysdev suspend, resume and shutdown operations 2011-05-11 21:37:15 +02:00
kfifo.c
kmod.c kmod: prevent kmod_loop_msg overflow in __request_module() 2011-11-11 09:35:48 -08:00
kprobes.c kprobes: adjust "fix a memory leak in function pre_handler_kretprobe()" 2012-03-12 10:32:57 -07:00
ksysfs.c kernel/ksysfs.c: expose file_caps_enabled in sysfs 2011-04-19 16:45:51 -07:00
kthread.c cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowed 2011-05-28 17:02:57 +02:00
latencytop.c Fix common misspellings 2011-03-31 11:26:23 -03:00
lockdep.c lockdep: Fix lock_is_held() on recursion 2011-06-07 12:25:50 +02:00
lockdep_internals.h
lockdep_proc.c lockdep: Remove unused 'factor' variable from lockdep_stats_show() 2011-03-23 13:54:47 +01:00
lockdep_states.h
Makefile cgroup: remove the ns_cgroup 2011-05-26 17:12:34 -07:00
module.c module: Remove module size limit 2012-04-02 09:27:20 -07:00
mutex-debug.c mutex: Use p->on_cpu for the adaptive spin 2011-04-14 08:52:33 +02:00
mutex-debug.h mutex: Use p->on_cpu for the adaptive spin 2011-04-14 08:52:33 +02:00
mutex.c lockdep, mutex: provide mutex_lock_nest_lock 2011-05-25 08:39:17 -07:00
mutex.h mutex: Use p->on_cpu for the adaptive spin 2011-04-14 08:52:33 +02:00
notifier.c
nsproxy.c cgroup: remove the ns_cgroup 2011-05-26 17:12:34 -07:00
padata.c Fix common misspellings 2011-03-31 11:26:23 -03:00
panic.c lockdep, bug: Exclude TAINT_FIRMWARE_WORKAROUND from disabling lockdep 2012-02-13 11:06:10 -08:00
params.c params.c: Use new strtobool function to process boolean inputs 2011-05-19 16:55:28 +09:30
pid.c next_pidmap: fix overflow condition 2011-04-18 10:35:30 -07:00
pid_namespace.c pidns: call pid_ns_prepare_proc() from create_pid_namespace() 2011-03-23 19:46:58 -07:00
pm_qos_params.c Merge branch 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6 2011-05-29 11:18:09 -07:00
posix-cpu-timers.c cputimer: Cure lock inversion 2011-10-25 07:10:14 +02:00
posix-timers.c posix-timers: RCU conversion 2011-05-24 12:10:51 +02:00
printk.c cap_syslog: don't use WARN_ONCE for CAP_SYS_ADMIN deprecation warning 2012-02-03 09:18:57 -08:00
profile.c kernel/profile.c: remove some duplicate code from profile_hits() 2011-05-26 17:12:37 -07:00
ptrace.c ptrace: ptrace_resume() shouldn't wake up !TASK_TRACED thread 2011-05-25 19:20:21 +02:00
range.c kernel/range.c: fix clean_sort_range() for the case of full array 2010-11-12 07:55:31 -08:00
rcupdate.c rcu: Use WARN_ON_ONCE for DEBUG_OBJECTS_RCU_HEAD warnings 2011-05-05 23:16:57 -07:00
rcutiny.c sanitize <linux/prefetch.h> usage 2011-05-20 12:50:29 -07:00
rcutiny_plugin.h rcu: Converge TINY_RCU expedited and normal boosting 2011-05-05 23:16:58 -07:00
rcutorture.c rcu: mark rcutorture boosting callback as being on-stack 2011-05-05 23:16:57 -07:00
rcutree.c rcu: Prevent RCU callbacks from executing before scheduler initialized 2011-07-13 08:17:56 -07:00
rcutree.h rcu: Move RCU_BOOST #ifdefs to header file 2011-06-16 16:12:05 -07:00
rcutree_plugin.h softirq,rcu: Inform RCU of irq_exit() activity 2011-07-20 10:50:12 -07:00
rcutree_trace.c rcu: use softirq instead of kthreads except when RCU_BOOST=y 2011-06-15 23:07:21 -07:00
relay.c relay: prevent integer overflow in relay_open() 2012-02-20 12:48:10 -08:00
res_counter.c memcg: res_counter_read_u64(): fix potential races on 32-bit machines 2011-03-23 19:46:22 -07:00
resource.c resource: ability to resize an allocated resource 2011-07-06 10:54:08 -07:00
rtmutex-debug.c rtmutex: Simplify PI algorithm and make highest prio task get lock 2011-01-27 21:13:51 -05:00
rtmutex-debug.h
rtmutex-tester.c rtmutex: tester: Remove the remaining BKL leftovers 2011-02-22 22:07:22 +01:00
rtmutex.c rtmutex: Simplify PI algorithm and make highest prio task get lock 2011-01-27 21:13:51 -05:00
rtmutex.h
rtmutex_common.h rtmutex: Simplify PI algorithm and make highest prio task get lock 2011-01-27 21:13:51 -05:00
rwsem.c
sched.c sched: Fix the relax_domain_level boot parameter 2012-06-17 11:23:12 -07:00
sched_autogroup.c Fix common misspellings 2011-03-31 11:26:23 -03:00
sched_autogroup.h sched, autogroup: Stop going ahead if autogroup is disabled 2011-02-23 11:33:59 +01:00
sched_clock.c sched: Add some clock info to sched_debug 2010-11-23 10:29:08 +01:00
sched_cpupri.c
sched_cpupri.h
sched_debug.c sched: Get rid of lock_depth 2011-04-24 13:18:38 +02:00
sched_fair.c sched: Break out cpu_power from the sched_group structure 2011-07-20 18:32:40 +02:00
sched_features.h sched: Allow for overlapping sched_domain spans 2011-07-20 18:32:41 +02:00
sched_idletask.c sched: Drop the rq argument to sched_class::select_task_rq() 2011-04-14 08:52:36 +02:00
sched_rt.c sched/rt: Fix task stack corruption under __ARCH_WANT_INTERRUPTS_ON_CTXSW 2012-02-13 11:06:08 -08:00
sched_stats.h sched: More sched_domain iterations fixes 2011-05-28 17:02:54 +02:00
sched_stoptask.c sched: Drop the rq argument to sched_class::select_task_rq() 2011-04-14 08:52:36 +02:00
seccomp.c
semaphore.c
signal.c ptrace: don't clear GROUP_STOP_SIGMASK on double-stop 2011-11-11 09:36:23 -08:00
smp.c generic-ipi: Fix kexec boot crash by initializing call_single_queue before enabling interrupts 2011-06-17 10:17:12 +02:00
softirq.c softirq,rcu: Inform RCU of irq_exit() activity 2011-07-20 10:50:12 -07:00
spinlock.c
srcu.c rcu: demote SRCU_SYNCHRONIZE_DELAY from kernel-parameter status 2011-01-14 04:56:49 -08:00
stacktrace.c
stop_machine.c x86, mtrr: lock stop machine during MTRR rendezvous sequence 2011-08-29 13:29:08 -07:00
sys.c Avoid using variable-length arrays in kernel/sys.c 2011-10-25 07:10:14 +02:00
sys_ni.c ipc: Add missing sys_ni entries for ipc/compat.c functions 2011-05-20 13:53:02 -07:00
sysctl.c sysctl: fix write access to dmesg_restrict/kptr_restrict 2012-04-13 08:14:07 -07:00
sysctl_binary.c binary_sysctl(): fix memory leak 2012-01-06 14:13:50 -08:00
sysctl_check.c sysctl_check: drop dead code 2011-03-23 19:46:51 -07:00
taskstats.c Make TASKSTATS require root access 2011-12-21 12:57:40 -08:00
test_kprobes.c
time.c time: Change jiffies_to_clock_t() argument type to unsigned long 2011-11-11 09:35:52 -08:00
timeconst.pl
timer.c timers: Consider slack value in mod_timer() 2011-06-03 15:02:32 +02:00
tracepoint.c jump label: Introduce static_branch() interface 2011-04-04 12:48:08 -04:00
tsacct.c taskstats: use real microsecond granularity for CPU times 2010-10-27 18:03:17 -07:00
uid16.c userns: user namespaces: convert several capable() calls 2011-03-23 19:47:08 -07:00
up.c
user-return-notifier.c Fix common misspellings 2011-03-31 11:26:23 -03:00
user.c userns: add a user_namespace as creator/owner of uts_namespace 2011-03-23 19:46:59 -07:00
user_namespace.c user_ns: improve the user_ns on-the-slab packaging 2011-01-13 08:03:18 -08:00
utsname.c ns proc: Add support for the uts namespace 2011-05-10 14:35:35 -07:00
utsname_sysctl.c
wait.c Fix common misspellings 2011-03-31 11:26:23 -03:00
watchdog.c kernel/watchdog.c: Use proper ANSI C prototypes 2011-05-23 21:07:40 -07:00
workqueue.c workqueue: skip nr_running sanity check in worker_enter_idle() if trustee is active 2012-06-01 15:12:56 +08:00
workqueue_sched.h