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Thomas Gleixner 084c895d3c tick: Prevent uncontrolled switch to oneshot mode 
commit 1f73a9806b upstream.

When the system switches from periodic to oneshot mode, the broadcast
logic causes a possibility that a CPU which has not yet switched to
oneshot mode puts its own clock event device into oneshot mode without
updating the state and the timer handler.

CPU0				CPU1
				per cpu tickdev is in periodic mode
				and switched to broadcast

Switch to oneshot mode
 tick_broadcast_switch_to_oneshot()
  cpumask_copy(tick_oneshot_broacast_mask,
	       tick_broadcast_mask);

  broadcast device mode = oneshot

				Timer interrupt

				irq_enter()
				 tick_check_oneshot_broadcast()
				  dev->set_mode(ONESHOT);

				tick_handle_periodic()
				 if (dev->mode == ONESHOT)
				   dev->next_event += period;
				   FAIL.

We fail, because dev->next_event contains KTIME_MAX, if the device was
in periodic mode before the uncontrolled switch to oneshot happened.

We must copy the broadcast bits over to the oneshot mask, because
otherwise a CPU which relies on the broadcast would not been woken up
anymore after the broadcast device switched to oneshot mode.

So we need to verify in tick_check_oneshot_broadcast() whether the CPU
has already switched to oneshot mode. If not, leave the device
untouched and let the CPU switch controlled into oneshot mode.

This is a long standing bug, which was never noticed, because the main
user of the broadcast x86 cannot run into that scenario, AFAICT. The
nonarchitected timer mess of ARM creates a gazillion of differently
broken abominations which trigger the shortcomings of that broadcast
code, which better had never been necessary in the first place.

Reported-and-tested-by: Stehle Vincent-B46079 <B46079@freescale.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>,
Cc: Mark Rutland <mark.rutland@arm.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1307012153060.4013@ionos.tec.linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-25 14:07:29 -07:00
..
cpu idle: Enable interrupts in the weak arch_cpu_idle() implementation 2013-06-14 23:01:05 +02:00
debug kgdb/sysrq: fix inconstistent help message of sysrq key 2013-04-30 17:04:10 -07:00
events hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot() 2013-06-20 17:57:01 +02:00
gcov kernel/gcov: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:39:33 -08:00
irq genirq: Fix can_request_irq() for IRQs without an action 2013-07-21 18:21:27 -07:00
power Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2013-05-02 19:40:34 -07:00
sched Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-06-20 08:18:35 -10:00
time tick: Prevent uncontrolled switch to oneshot mode 2013-07-25 14:07:29 -07:00
trace tracing: Fix outputting formats of x86-tsc and counter when use trace_clock 2013-06-11 13:58:46 -04:00
.gitignore kernel/hz.bc: ignore. 2013-04-22 07:09:06 -07:00
acct.c fs: Fix hang with BSD accounting on frozen filesystem 2013-05-04 14:57:58 -04:00
async.c async: rename and redefine async_func_ptr 2013-03-12 13:59:14 -07:00
audit_tree.c kernel/audit_tree.c:audit_add_tree_rule(): protect `rule' from kill_rules() 2013-06-12 16:29:46 -07:00
audit_watch.c audit: catch possible NULL audit buffers 2013-01-11 14:54:55 -08:00
audit.c audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE 2013-06-12 16:29:45 -07:00
audit.h Merge git://git.infradead.org/users/eparis/audit 2013-05-11 14:29:11 -07:00
auditfilter.c auditfilter.c: fix kernel-doc warnings 2013-05-24 16:22:52 -07:00
auditsc.c audit: Make testing for a valid loginuid explicit. 2013-05-07 22:27:15 -04:00
backtracetest.c
bounds.c
capability.c Add file_ns_capable() helper function for open-time capability checking 2013-04-14 10:06:31 -07:00
cgroup_freezer.c cgroup: rename ->create/post_create/pre_destroy/destroy() to ->css_alloc/online/offline/free() 2012-11-19 08:13:38 -08:00
cgroup.c cgroup: fix umount vs cgroup_event_remove() race 2013-07-21 18:21:25 -07:00
compat.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2013-05-01 07:21:43 -07:00
configs.c proc: Supply PDE attribute setting accessor functions 2013-05-01 17:29:18 -04:00
context_tracking.c Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-06-20 08:18:35 -10:00
cpu_pm.c kernel/cpu_pm.c: fix various typos 2012-05-31 17:49:27 -07:00
cpu.c CPU hotplug: provide a generic helper to disable/enable CPU hotplug 2013-06-12 16:29:44 -07:00
cpuset.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
crash_dump.c
cred.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-12-18 10:55:28 -08:00
delayacct.c cputime: Use accessors to read task cputime stats 2013-01-27 19:23:31 +01:00
dma.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
elfcore.c
exec_domain.c
exit.c move exit_task_namespaces() outside of exit_notify() 2013-06-15 05:39:08 +04:00
extable.c extable: Flip the sorting message 2013-04-15 13:25:16 +02:00
fork.c Merge branch 'for-3.10/drivers' of git://git.kernel.dk/linux-block 2013-05-08 11:51:05 -07:00
freezer.c freezer: change ptrace_stop/do_signal_stop to use freezable_schedule() 2012-10-26 14:27:49 -07:00
futex_compat.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2013-02-23 18:50:11 -08:00
futex.c futex: Take hugepages into account when generating futex_key 2013-07-13 11:42:26 -07:00
groups.c userns: Convert in_group_p and in_egroup_p to use kgid_t 2012-05-03 03:29:33 -07:00
hrtimer.c Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-05-05 13:23:27 -07:00
hung_task.c hung task debugging: Inject NMI when hung and going to panic 2012-04-25 12:39:25 +02:00
irq_work.c Merge branch 'nohz/printk-v8' into irq/core 2013-02-05 00:48:46 +01:00
itimer.c itimer: Use printk_once instead of WARN_ONCE 2012-04-10 11:00:30 +02:00
jump_label.c jump_label: Export jump_label_rate_limit() 2012-08-06 19:00:35 +03:00
kallsyms.c kernel: kallsyms: memory override issue, need check destination buffer length 2013-04-15 15:17:26 +09:30
kcmp.c kcmp: include linux/ptrace.h 2012-12-20 17:40:19 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks locking: Adjust spin lock inlining Kconfig options 2012-09-13 17:56:13 +02:00
Kconfig.preempt locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage 2012-03-23 13:18:57 +01:00
kexec.c kexec: Use min() and min_t() to simplify logic 2013-04-30 17:04:07 -07:00
kmod.c usermodehelper: check subprocess_info->path != NULL 2013-05-16 12:01:11 -07:00
kprobes.c kprobes: Fix to free gone and unused optprobes 2013-05-28 10:37:59 +02:00
ksysfs.c Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-12-11 18:10:49 -08:00
kthread.c kthread: implement probe_kthread_data() 2013-04-30 17:04:02 -07:00
latencytop.c
lglock.c brlocks/lglocks: turn into functions 2012-05-29 23:28:41 -04:00
lockdep_internals.h
lockdep_proc.c lockdep: Use KSYM_NAME_LEN'ed buffer for __get_key_name() 2012-10-24 12:39:09 +02:00
lockdep_states.h
lockdep.c Merge branch 'for-3.10/drivers' of git://git.kernel.dk/linux-block 2013-05-08 11:51:05 -07:00
Makefile We get rid of the general module prefix confusion with a binary config option, 2013-05-05 10:58:06 -07:00
modsign_certificate.S CONFIG_SYMBOL_PREFIX: cleanup. 2013-03-15 15:09:43 +10:30
modsign_pubkey.c keys: use keyring_alloc() to create module signing keyring 2012-12-20 17:40:21 -08:00
module_signing.c MODSIGN: Don't use enum-type bitfields in module signature info block 2012-12-05 11:27:24 +10:30
module-internal.h MODSIGN: Move the magic string to the end of a module and eliminate the search 2012-10-19 17:30:40 -07:00
module.c module: do percpu allocation after uniqueness check. No, really! 2013-07-13 11:42:26 -07:00
mutex-debug.c
mutex-debug.h
mutex.c mutex: Back out architecture specific check for negative mutex count 2013-04-19 09:33:36 +02:00
mutex.h
notifier.c
nsproxy.c proc: Split the namespace stuff out into linux/proc_ns.h 2013-05-01 17:29:39 -04:00
padata.c padata: use __this_cpu_read per-cpu helper 2012-12-06 17:16:23 +08:00
panic.c dump_stack: implement arch-specific hardware description in task dumps 2013-04-30 17:04:02 -07:00
params.c params: Fix potential memory leak in add_sysfs_param() 2013-03-18 11:40:21 +00:00
pid_namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
pid.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
posix-cpu-timers.c posix_timers: Fix pre-condition to stop the tick on full dynticks 2013-04-22 19:59:25 +02:00
posix-timers.c posix-timers: Remove unused variable 2013-04-18 12:51:19 +02:00
printk.c kmsg: honor dmesg_restrict sysctl on /dev/kmsg 2013-06-12 16:29:44 -07:00
profile.c proc: Supply PDE attribute setting accessor functions 2013-05-01 17:29:18 -04:00
ptrace.c Fix: kernel/ptrace.c: ptrace_peek_siginfo() missing __put_user() validation 2013-06-29 11:29:08 -07:00
range.c range: Do not add new blank slot with add_range_with_merge 2013-06-18 11:32:10 -05:00
rcu.h rcu: Provide RCU CPU stall warnings for tiny RCU 2013-01-28 22:06:21 -08:00
rcupdate.c Merge branches 'doctorture.2013.01.29a', 'fixes.2013.01.26a', 'tagcb.2013.01.24a' and 'tiny.2013.01.29b' into HEAD 2013-01-28 22:25:21 -08:00
rcutiny_plugin.h rcu: Provide RCU CPU stall warnings for tiny RCU 2013-01-28 22:06:21 -08:00
rcutiny.c Merge branches 'doctorture.2013.01.29a', 'fixes.2013.01.26a', 'tagcb.2013.01.24a' and 'tiny.2013.01.29b' into HEAD 2013-01-28 22:25:21 -08:00
rcutorture.c rcu: Allow rcutorture to be built at low optimization levels 2013-02-04 12:18:20 -08:00
rcutree_plugin.h rcu: Don't allocate bootmem from rcu_init() 2013-05-15 10:41:12 -07:00
rcutree_trace.c rcutrace: single_open() leaks 2013-05-05 00:16:35 -04:00
rcutree.c rcu: Fix deadlock with CPU hotplug, RCU GP init, and timer migration 2013-06-10 13:37:12 -07:00
rcutree.h rcu: Don't call wakeup() with rcu_node structure ->lock held 2013-06-10 13:37:11 -07:00
relay.c Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
res_counter.c res_counter: return amount of charges after res_counter_uncharge() 2012-12-18 15:02:12 -08:00
resource.c mem hotunplug: fix kfree() of bootmem memory 2013-04-29 15:54:40 -07:00
rtmutex_common.h
rtmutex-debug.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
rtmutex-debug.h
rtmutex-tester.c locking/rtmutex/tester: Set correct permissions on sysfs files 2013-04-10 14:48:37 +02:00
rtmutex.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
rtmutex.h
rwsem.c Revert "rw_semaphore: remove up/down_read_non_owner" 2013-03-23 15:53:52 -07:00
seccomp.c seccomp: allow BPF_XOR based ALU instructions. 2013-03-26 11:07:19 +11:00
semaphore.c semaphore: use `bool' type for semaphore_waiter's up 2013-04-30 17:04:08 -07:00
signal.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-05-01 14:08:52 -07:00
smp.c kernel/smp.c: cleanups 2013-04-30 17:04:03 -07:00
smpboot.c kthread: Prevent unpark race which puts threads on the wrong cpu 2013-04-12 14:18:43 +02:00
smpboot.h smpboot: Provide infrastructure for percpu hotplug threads 2012-08-13 17:01:07 +02:00
softirq.c Fix lockup related to stop_machine being stuck in __do_softirq. 2013-06-10 17:46:57 -07:00
spinlock.c locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage 2012-03-23 13:18:57 +01:00
srcu.c srcu: use ACCESS_ONCE() to access sp->completed in srcu_read_lock() 2013-02-07 15:19:36 -08:00
stacktrace.c
stop_machine.c stop_machine: Mark per cpu stopper enabled early 2013-02-26 22:25:17 +01:00
sys_ni.c unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE 2013-05-09 13:46:38 -04:00
sys.c reboot: rigrate shutdown/reboot to boot cpu 2013-06-12 16:29:44 -07:00
sysctl_binary.c switch compat_sys_sysctl to COMPAT_SYSCALL_DEFINE 2013-05-09 14:53:20 -04:00
sysctl.c mm: replace hardcoded 3% with admin_reserve_pages knob 2013-04-29 15:54:36 -07:00
task_work.c task_work: task_work_add() should not succeed after exit_task_work() 2012-09-13 16:47:34 +02:00
taskstats.c taskstats: cgroupstats_user_cmd() may leak on error 2012-10-06 03:05:31 +09:00
test_kprobes.c kernel/: rename random32() to prandom_u32() 2013-04-29 18:28:42 -07:00
time.c timekeeping: Use inject_offset in warp_clock 2013-03-15 16:50:20 -07:00
timeconst.bc kernel: Replace timeconst.pl with a bc script 2013-02-16 23:17:25 +01:00
timer.c timer: Fix jiffies wrap behavior of round_jiffies_common() 2013-07-21 18:21:31 -07:00
tracepoint.c Tracing updates for Linux 3.10 2013-04-29 13:55:38 -07:00
tsacct.c cputime: Use accessors to read task cputime stats 2013-01-27 19:23:31 +01:00
uid16.c make SYSCALL_DEFINE<n>-generated wrappers do asmlinkage_protect 2013-03-03 22:58:33 -05:00
up.c
user_namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
user-return-notifier.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
user.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
utsname_sysctl.c kernel/utsname_sysctl.c: put get/get_uts() into CONFIG_PROC_SYSCTL code block 2013-02-27 19:10:22 -08:00
utsname.c proc: Split the namespace stuff out into linux/proc_ns.h 2013-05-01 17:29:39 -04:00
wait.c propagate name change to comments in kernel source 2012-12-06 10:39:54 +01:00
watchdog.c watchdog: Add comments to explain the watchdog_disabled variable 2013-03-14 08:24:05 +01:00
workqueue_internal.h workqueue: include workqueue info when printing debug dump of a worker task 2013-04-30 17:04:02 -07:00
workqueue.c workqueue: don't perform NUMA-aware allocations on offline nodes in wq_numa_init() 2013-05-15 14:24:24 -07:00