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Frederic Weisbecker e5ab012c32 nohz: Make tick_nohz_irq_exit() irq safe 
As it stands, irq_exit() may or may not be called with
irqs disabled, depending on __ARCH_IRQ_EXIT_IRQS_DISABLED
that the arch can define.

It makes tick_nohz_irq_exit() unsafe. For example two
interrupts can race in tick_nohz_stop_sched_tick(): the inner
most one computes the expiring time on top of the timer list,
then it's interrupted right before reprogramming the
clock. The new interrupt enqueues a new timer list timer,
it reprogram the clock to take it into account and it exits.
The CPUs resumes the inner most interrupt and performs the clock
reprogramming without considering the new timer list timer.

This regression has been introduced by:
     280f06774a
     ("nohz: Separate out irq exit and idle loop dyntick logic")

Let's fix it right now with the appropriate protections.

A saner long term solution will be to remove
__ARCH_IRQ_EXIT_IRQS_DISABLED and mandate that irq_exit() is called
with interrupts disabled.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>
Cc: <stable@vger.kernel.org> #v3.2+
Link: http://lkml.kernel.org/r/1361373336-11337-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
 		2013-02-21 20:52:24 +01:00
..
debug module: add new state MODULE_STATE_UNFORMED. 2013-01-12 13:27:05 +10:30
events Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-19 17:49:41 -08:00
gcov
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irq Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-19 19:07:27 -08:00
power Merge branch 'for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2012-12-12 08:18:24 -08:00
sched Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-19 18:19:48 -08:00
time nohz: Make tick_nohz_irq_exit() irq safe 2013-02-21 20:52:24 +01:00
trace Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-19 18:19:48 -08:00
.gitignore
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Kconfig.freezer
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Kconfig.hz
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Kconfig.locks locking: Adjust spin lock inlining Kconfig options 2012-09-13 17:56:13 +02:00
Kconfig.preempt
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Makefile Nothing all that exciting; a new module-from-fd syscall for those who want 2012-12-19 07:55:08 -08:00
acct.c cputime: Use accessors to read task cputime stats 2013-01-27 19:23:31 +01:00
async.c async: fix __lowest_in_progress() 2013-01-22 16:21:24 -08:00
audit.c kernel/audit.c: avoid negative sleep durations 2013-01-11 14:54:56 -08:00
audit.h audit: optimize audit_compare_dname_path 2012-10-12 00:32:02 -04:00
audit_tree.c audit: catch possible NULL audit buffers 2013-01-11 14:54:55 -08:00
audit_watch.c audit: catch possible NULL audit buffers 2013-01-11 14:54:55 -08:00
auditfilter.c audit: fix auditfilter.c kernel-doc warnings 2013-01-10 14:35:23 -08:00
auditsc.c audit: catch possible NULL audit buffers 2013-01-11 14:54:55 -08:00
backtracetest.c
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bounds.c
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capability.c
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cgroup.c Merge branch 'akpm' (Andrew's patch-bomb) 2012-12-17 20:58:12 -08:00
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
compat.c x32: fix sigtimedwait 2012-12-26 01:15:03 -05:00
configs.c
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context_tracking.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-19 18:19:48 -08:00
cpu.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-19 19:04:55 -08:00
cpu_pm.c
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cpuset.c cpuset: use N_MEMORY instead N_HIGH_MEMORY 2012-12-12 17:38:32 -08:00
crash_dump.c
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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
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elfcore.c
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exec_domain.c
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exit.c cputime: Use accessors to read task cputime stats 2013-01-27 19:23:31 +01:00
extable.c
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fork.c This implements the cputime accounting on full dynticks CPUs. 2013-02-05 13:10:33 +01:00
freezer.c freezer: change ptrace_stop/do_signal_stop to use freezable_schedule() 2012-10-26 14:27:49 -07:00
futex.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
futex_compat.c
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groups.c
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hrtimer.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-19 19:05:45 -08:00
hung_task.c
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irq_work.c Merge branch 'nohz/printk-v8' into irq/core 2013-02-05 00:48:46 +01:00
itimer.c
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jump_label.c jump_label: Export jump_label_rate_limit() 2012-08-06 19:00:35 +03:00
kallsyms.c
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kcmp.c kcmp: include linux/ptrace.h 2012-12-20 17:40:19 -08:00
kexec.c kdump: remove unneeded include 2012-10-06 03:05:19 +09:00
kfifo.c
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kmod.c Bury the conditionals from kernel_thread/kernel_execve series 2012-12-19 18:07:38 -05:00
kprobes.c kprobes/x86: Move ftrace-based kprobe code into kprobes-ftrace.c 2013-01-21 13:22:36 -05:00
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: use N_MEMORY instead N_HIGH_MEMORY 2012-12-12 17:38:33 -08:00
latencytop.c
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lglock.c
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lockdep.c lockdep: Check if nested lock is actually held 2012-09-13 17:00:44 +02:00
lockdep_internals.h
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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
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modsign_certificate.S MODSIGN: Avoid using .incbin in C source 2012-12-14 13:06:44 +10:30
modsign_pubkey.c keys: use keyring_alloc() to create module signing keyring 2012-12-20 17:40:21 -08:00
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: fix missing module_mutex unlock 2013-01-20 20:22:58 -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
mutex-debug.c
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mutex-debug.h
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mutex.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
mutex.h
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notifier.c
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nsproxy.c userns: Implement unshare of the user namespace 2012-11-20 04:18:14 -08:00
padata.c padata: use __this_cpu_read per-cpu helper 2012-12-06 17:16:23 +08:00
panic.c panic: fix a possible deadlock in panic() 2012-07-30 17:25:13 -07:00
params.c
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pid.c kernel/pid.c: reenable interrupts when alloc_pid() fails because init has exited 2013-02-12 14:34:00 -08:00
pid_namespace.c pidns: Stop pid allocation when init dies 2012-12-25 16:10:05 -08:00
posix-cpu-timers.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-19 19:05:45 -08:00
posix-timers.c posix-timers: Fix clock_adjtime to always return timex data on success 2013-01-15 18:16:07 -08:00
printk.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-19 17:47:58 -08:00
profile.c profiling: Remove unused timer hook 2013-01-24 15:37:26 +01:00
ptrace.c uprobes: Add exports for module use 2013-02-08 17:47:13 +01:00
range.c
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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.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
rcutorture.c rcu: Allow rcutorture to be built at low optimization levels 2013-02-04 12:18:20 -08:00
rcutree.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
rcutree.h 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
rcutree_plugin.h rcu: Make rcu_nocb_poll an early_param instead of module_param 2013-01-08 14:12:19 -08:00
rcutree_trace.c rcu: Separate accounting of callbacks from callback-free CPUs 2012-11-16 10:05:57 -08:00
relay.c
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res_counter.c res_counter: return amount of charges after res_counter_uncharge() 2012-12-18 15:02:12 -08:00
resource.c kernel/resource.c: fix stack overflow in __reserve_region_with_split() 2012-10-06 03:05:31 +09:00
rtmutex-debug.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
rtmutex-debug.h
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rtmutex-tester.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
rtmutex.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
rtmutex.h
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rtmutex_common.h
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rwsem.c lockdep, rwsem: provide down_write_nest_lock() 2013-01-11 14:54:55 -08:00
seccomp.c seccomp: Make syscall skipping and nr changes more consistent 2012-10-02 21:14:29 +10:00
semaphore.c
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signal.c This implements the cputime accounting on full dynticks CPUs. 2013-02-05 13:10:33 +01:00
smp.c smp: Fix SMP function call empty cpu mask race 2013-01-28 11:21:57 +01:00
smpboot.c smpboot: Allow selfparking per cpu threads 2013-02-14 15:29:37 +01:00
smpboot.h smpboot: Provide infrastructure for percpu hotplug threads 2012-08-13 17:01:07 +02:00
softirq.c cputime: Safely read cputime of full dynticks CPUs 2013-01-27 20:35:47 +01:00
spinlock.c
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srcu.c srcu: use ACCESS_ONCE() to access sp->completed in srcu_read_lock() 2013-02-07 15:19:36 -08:00
stacktrace.c
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stop_machine.c stop_machine: Use smpboot threads 2013-02-14 15:29:38 +01:00
sys.c cputime: Rename thread_group_times to thread_group_cputime_adjusted 2012-11-28 17:07:57 +01:00
sys_ni.c module: add syscall to load module from fd 2012-12-14 13:05:22 +10:30
sysctl.c sched/rt: Add a tuning knob to allow changing SCHED_RR timeslice 2013-02-07 20:51:07 +01:00
sysctl_binary.c pidns: Use task_active_pid_ns where appropriate 2012-11-19 05:59:09 -08:00
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
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time.c time, Fix setting of hardware clock in NTP code 2013-02-08 15:07:05 -08:00
timeconst.pl timeconst.pl: Eliminate Perl warning 2013-02-07 17:14:08 -08:00
timer.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-19 18:19:48 -08:00
tracepoint.c
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tsacct.c cputime: Use accessors to read task cputime stats 2013-01-27 19:23:31 +01:00
uid16.c
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up.c
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user-return-notifier.c
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user.c proc: Usable inode numbers for the namespace file descriptors. 2012-11-20 04:19:49 -08:00
user_namespace.c userns: Fix typo in description of the limitation of userns_install 2012-12-14 18:36:36 -08:00
utsname.c userns: Require CAP_SYS_ADMIN for most uses of setns. 2012-12-14 16:12:03 -08:00
utsname_sysctl.c
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wait.c propagate name change to comments in kernel source 2012-12-06 10:39:54 +01:00
watchdog.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
workqueue.c Merge branch 'for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2012-12-12 08:15:13 -08:00
workqueue_sched.h
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