Steven Rostedt 7614c3dc74 ftrace: Use schedule_on_each_cpu() as a heavy synchronize_sched() ... The function tracer uses preempt_disable/enable_notrace() for synchronization between reading registered ftrace_ops and unregistering them. Most of the ftrace_ops are global permanent structures that do not require this synchronization. That is, ops may be added and removed from the hlist but are never freed, and wont hurt if a synchronization is missed. But this is not true for dynamically created ftrace_ops or control_ops, which are used by the perf function tracing. The problem here is that the function tracer can be used to trace kernel/user context switches as well as going to and from idle. Basically, it can be used to trace blind spots of the RCU subsystem. This means that even though preempt_disable() is done, a synchronize_sched() will ignore CPUs that haven't made it out of user space or idle. These can include functions that are being traced just before entering or exiting the kernel sections. To implement the RCU synchronization, instead of using synchronize_sched() the use of schedule_on_each_cpu() is performed. This means that when a dynamically allocated ftrace_ops, or a control ops is being unregistered, all CPUs must be touched and execute a ftrace_sync() stub function via the work queues. This will rip CPUs out from idle or in dynamic tick mode. This only happens when a user disables perf function tracing or other dynamically allocated function tracers, but it allows us to continue to debug RCU and context tracking with function tracing. Link: http://lkml.kernel.org/r/1369785676.15552.55.camel@gandalf.local.home Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>		2013-06-11 18:38:50 -04:00
..
cpu	rcu/idle: Wrap cpu-idle poll mode within rcu_idle_enter/exit	2013-05-14 17:43:29 +02:00
debug	kgdb/sysrq: fix inconstistent help message of sysrq key	2013-04-30 17:04:10 -07:00
events	perf: Factor out auxiliary events notification	2013-05-07 13:17:29 +02:00
gcov	kernel/gcov: remove depends on CONFIG_EXPERIMENTAL	2013-01-11 11:39:33 -08:00
irq	irqdomain: document the simple domain first_irq	2013-06-08 21:15:09 +01:00
power	Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux	2013-05-02 19:40:34 -07:00
sched	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
time	Merge branch 'fortglx/3.10/time' of git://git.linaro.org/people/jstultz/linux into timers/urgent	2013-05-29 09:55:01 +02:00
trace	ftrace: Use schedule_on_each_cpu() as a heavy synchronize_sched()	2013-06-11 18:38:50 -04:00
.gitignore	kernel/hz.bc: ignore.	2013-04-22 07:09:06 -07:00
Kconfig.freezer	…
Kconfig.hz	…
Kconfig.locks	locking: Adjust spin lock inlining Kconfig options	2012-09-13 17:56:13 +02:00
Kconfig.preempt	…
Makefile	We get rid of the general module prefix confusion with a binary config option,	2013-05-05 10:58:06 -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.c	Merge git://git.infradead.org/users/eparis/audit	2013-05-11 14:29:11 -07:00
audit.h	Merge git://git.infradead.org/users/eparis/audit	2013-05-11 14:29:11 -07:00
audit_tree.c	kernel/audit_tree.c: tree will leak memory when failure occurs in audit_trim_trees()	2013-04-29 15:54:26 -07:00
audit_watch.c	audit: catch possible NULL audit buffers	2013-01-11 14:54:55 -08:00
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.c	cgroup: warn about mismatching options of a new mount of an existing hierarchy	2013-05-29 07:59:39 +09:00
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	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-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	…
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	…
elfcore.c	…
exec_domain.c	…
exit.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
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.c	futex: fix kernel-doc notation and spello	2013-03-12 20:42:10 -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
groups.c	…
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	…
irq_work.c	Merge branch 'nohz/printk-v8' into irq/core	2013-02-05 00:48:46 +01:00
itimer.c	…
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
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 a double lock bug of kprobe_mutex	2013-04-18 08:58:38 -07:00
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	…
lockdep.c	Merge branch 'for-3.10/drivers' of git://git.kernel.dk/linux-block	2013-05-08 11:51:05 -07:00
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	…
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-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	kmemleak: No need for scanning specific module sections	2013-05-17 09:53:36 +01:00
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	…
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.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_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
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	aio: don't include aio.h in sched.h	2013-05-07 20:16:25 -07:00
profile.c	proc: Supply PDE attribute setting accessor functions	2013-05-01 17:29:18 -04:00
ptrace.c	aio: don't include aio.h in sched.h	2013-05-07 20:16:25 -07:00
range.c	x86, range: fix missing merge during add range	2013-05-17 11:49:10 -07:00
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.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 commit '8700c95adb03' into timers/nohz	2013-05-02 17:54:19 +02:00
rcutree.h	Merge commit '8700c95adb03' into timers/nohz	2013-05-02 17:54:19 +02:00
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
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-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	…
rtmutex_common.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	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
spinlock.c	…
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.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
sys_ni.c	unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE	2013-05-09 13:46:38 -04:00
sysctl.c	mm: replace hardcoded 3% with admin_reserve_pages knob	2013-04-29 15:54:36 -07:00
sysctl_binary.c	switch compat_sys_sysctl to COMPAT_SYSCALL_DEFINE	2013-05-09 14:53:20 -04:00
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	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-05-15 14:05:17 -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-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
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
utsname.c	proc: Split the namespace stuff out into linux/proc_ns.h	2013-05-01 17:29:39 -04:00
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
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.c	workqueue: don't perform NUMA-aware allocations on offline nodes in wq_numa_init()	2013-05-15 14:24:24 -07:00
workqueue_internal.h	workqueue: include workqueue info when printing debug dump of a worker task	2013-04-30 17:04:02 -07:00