Frederic Weisbecker c85a17e226 tracing/urgent: fix unbalanced ftrace_start_up ... Perfcounter reports the following stats for a wide system profiling: # # (2364 samples) # # Overhead Symbol # ........ ...... # 15.40% [k] mwait_idle_with_hints 8.29% [k] read_hpet 5.75% [k] ftrace_caller 3.60% [k] ftrace_call [...] This snapshot has been taken while neither the function tracer nor the function graph tracer was running. With dynamic ftrace, such results show a wrong ftrace behaviour because all calls to ftrace_caller or ftrace_graph_caller (the patched calls to mcount) are supposed to be patched into nop if none of those tracers are running. The problem occurs after the first run of the function tracer. Once we launch it a second time, the callsites will never be nopped back, unless you set custom filters. For example it happens during the self tests at boot time. The function tracer selftest runs, and then the dynamic tracing is tested too. After that, the callsites are left un-nopped. This is because the reset callback of the function tracer tries to unregister two ftrace callbacks in once: the common function tracer and the function tracer with stack backtrace, regardless of which one is currently in use. It then creates an unbalance on ftrace_start_up value which is expected to be zero when the last ftrace callback is unregistered. When it reaches zero, the FTRACE_DISABLE_CALLS is set on the next ftrace command, triggering the patching into nop. But since it becomes unbalanced, ie becomes lower than zero, if the kernel functions are patched again (as in every further function tracer runs), they won't ever be nopped back. Note that ftrace_call and ftrace_graph_call are still patched back to ftrace_stub in the off case, but not the callers of ftrace_call and ftrace_graph_caller. It means that the tracing is well deactivated but we waste a useless call into every kernel function. This patch just unregisters the right ftrace_ops for the function tracer on its reset callback and ignores the other one which is not registered, fixing the unbalance. The problem also happens is .30 Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: stable@kernel.org		2009-06-20 06:28:46 +02:00
..
irq	irq: slab alloc for default irq_affinity	2009-06-12 13:50:23 +03:00
power	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2009-06-14 13:46:25 -07:00
time	Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6	2009-06-11 09:01:14 +03:00
trace	tracing/urgent: fix unbalanced ftrace_start_up	2009-06-20 06:28:46 +02:00
.gitignore
acct.c	[CVE-2009-0029] System call wrappers part 04	2009-01-14 14:15:19 +01:00
async.c	async: Fix lack of boot-time console due to insufficient synchronization	2009-06-08 12:31:53 -07:00
audit.c	Audit: remove spaces from audit_log_d_path	2009-04-05 13:49:04 -04:00
audit.h	fixing audit rule ordering mess, part 1	2009-01-04 15:14:41 -05:00
audit_tree.c	Switch collect_mounts() to struct path	2009-06-11 21:36:01 -04:00
auditfilter.c	inotify: use GFP_NOFS in kernel_event() to work around a lockdep false-positive	2009-05-06 16:36:09 -07:00
auditsc.c	Audit: remove spaces from audit_log_d_path	2009-04-05 13:49:04 -04:00
backtracetest.c
bounds.c
capability.c	[CVE-2009-0029] System call wrappers part 04	2009-01-14 14:15:19 +01:00
cgroup.c	Push BKL down into ->remount_fs()	2009-06-11 21:36:11 -04:00
cgroup_debug.c	debug cgroup: remove unneeded cgroup_lock	2009-04-02 19:04:54 -07:00
cgroup_freezer.c	freezer_cg: disable writing freezer.state of root cgroup	2008-11-12 17:17:16 -08:00
compat.c	signals: implement sys_rt_tgsigqueueinfo	2009-04-30 19:24:24 +02:00
configs.c	kernel/configs.c: remove useless comments	2008-10-20 08:52:34 -07:00
cpu.c	cpumask: use set_cpu_active in init/main.c	2009-03-30 22:05:12 +10:30
cpuset.c	x86: remove some alloc_bootmem_cpumask_var calling	2009-06-11 19:27:07 +03:00
cred-internals.h	CRED: Inaugurate COW credentials	2008-11-14 10:39:23 +11:00
cred.c	CRED: Rename cred_exec_mutex to reflect that it's a guard against ptrace	2009-05-11 08:15:36 +10:00
delayacct.c	schedstat: consolidate per-task cpu runtime stats	2008-12-18 13:54:01 +01:00
dma-coherent.c	dma-coherent: Restore dma_alloc_from_coherent() large alloc fall back policy.	2009-01-21 18:51:53 +09:00
dma.c	kernel/dma.c: remove a CVS keyword	2008-10-16 11:21:30 -07:00
exec_domain.c	Get rid of indirect include of fs_struct.h	2009-03-31 23:00:27 -04:00
exit.c	Merge branch 'perfcounters-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-06-11 14:01:07 -07:00
extable.c	Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-04-05 11:04:19 -07:00
fork.c	Merge branch 'linus' into perfcounters/core	2009-06-11 17:55:42 +02:00
freezer.c	freezer_cg: use thaw_process() in unfreeze_cgroup()	2008-10-30 11:38:45 -07:00
futex.c	futex: fix restart in wait_requeue_pi	2009-05-20 10:34:32 +02:00
futex_compat.c	CRED: Use RCU to access another task's creds and to release a task's own creds	2008-11-14 10:39:19 +11:00
hrtimer.c	hrtimer: fix rq->lock inversion (again)	2009-03-31 14:52:52 +02:00
hung_task.c	softlockup: ensure the task has been switched out once	2009-02-11 11:04:16 +01:00
itimer.c	timers: split process wide cpu clocks/timers	2009-02-05 13:04:33 +01:00
kallsyms.c	kernel/kallsyms.c: replace deprecated __initcall with device_initcall and fix whitespace	2009-06-09 22:37:52 +02:00
Kconfig.freezer	container freezer: implement freezer cgroup subsystem	2008-10-20 08:52:34 -07:00
Kconfig.hz
Kconfig.preempt	rcu: provide RCU options on non-preempt architectures too	2008-12-25 09:31:28 +01:00
kexec.c	PM core: rename suspend and resume functions	2009-06-12 21:32:31 +02:00
kfifo.c
kgdb.c	sysrq, intel_fb: fix sysrq g collision	2009-05-15 07:56:24 -05:00
kmod.c	kmod: Release sub_info on cred allocation failure.	2009-05-26 12:11:19 -07:00
kprobes.c	kprobes: fix to use text_mutex around arm/disarm kprobe	2009-05-08 16:23:48 -07:00
ksysfs.c	kernel/ksysfs.c:fix dependence on CONFIG_NET	2009-01-06 10:44:31 -08:00
kthread.c	tracing/events: move trace point headers into include/trace/events	2009-04-14 22:05:43 -04:00
latencytop.c	sched, latencytop: incorporate review feedback from Andrew Morton	2009-02-11 10:18:04 +01:00
lockdep.c	Merge branch 'linus' into tracing/core	2009-05-07 11:17:34 +02:00
lockdep_internals.h	lockdep: increase MAX_LOCKDEP_ENTRIES and MAX_LOCKDEP_CHAINS	2009-05-12 19:59:52 +02:00
lockdep_proc.c	lockstat: warn about disabled lock debugging	2009-02-14 23:28:28 +01:00
lockdep_states.h	lockdep: move state bit definitions around	2009-02-14 23:27:59 +01:00
Makefile	Merge branch 'linus' into perfcounters/core	2009-06-11 17:55:42 +02:00
marker.c	markers/tracpoints: fix non-modular build	2008-11-16 09:52:03 +01:00
module.c	module: trim exception table on init free.	2009-06-12 21:47:04 +09:30
mutex-debug.c	mutex: implement adaptive spinning	2009-01-14 18:09:02 +01:00
mutex-debug.h	mutex: implement adaptive spinning	2009-01-14 18:09:02 +01:00
mutex.c	Merge branch 'linus' into perfcounters/core	2009-06-11 17:55:42 +02:00
mutex.h	mutex: implement adaptive spinning	2009-01-14 18:09:02 +01:00
notifier.c	Merge commit 'v2.6.28-rc6' into core/debug	2008-11-26 08:22:50 +01:00
ns_cgroup.c	cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroups	2009-04-02 19:04:53 -07:00
nsproxy.c	User namespaces: set of cleanups (v2)	2008-11-24 18:57:41 -05:00
panic.c	Fix caller information for warn_slowpath_null	2009-05-16 13:41:28 -07:00
params.c	module_param: allow 'bool' module_params to be bool, not just int.	2009-06-12 21:46:58 +09:30
perf_counter.c	perf_counter: Add forward/backward attribute ABI compatibility	2009-06-12 14:28:52 +02:00
pid.c	pids: refactor vnr/nr_ns helpers to make them safe	2009-04-02 19:05:02 -07:00
pid_namespace.c	signals: zap_pid_ns_process() should use force_sig()	2009-04-02 19:04:58 -07:00
pm_qos_params.c
posix-cpu-timers.c	kernel/posix-cpu-timers.c: fix sparse warning	2009-04-30 08:08:31 +02:00
posix-timers.c	[CVE-2009-0029] System call wrappers part 05	2009-01-14 14:15:20 +01:00
printk.c	Merge branch 'printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-04-05 10:23:25 -07:00
profile.c	x86: remove some alloc_bootmem_cpumask_var calling	2009-06-11 19:27:07 +03:00
ptrace.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6	2009-06-11 10:01:41 -07:00
rcuclassic.c	kmemtrace, rcu: fix linux/rcutree.h and linux/rcuclassic.h dependencies	2009-04-03 12:23:02 +02:00
rcupdate.c	RCU: Don't try and predeclare inline funcs as it upsets some versions of gcc	2009-04-15 13:55:14 -07:00
rcupreempt.c	rcu: rcu_sched_grace_period(): kill the bogus flush_signals()	2009-05-05 20:28:05 +02:00
rcupreempt_trace.c	"Tree RCU": scalable classic RCU implementation	2008-12-18 21:56:04 +01:00
rcutorture.c	cpumask: convert rcutorture.c	2009-03-30 22:05:16 +10:30
rcutree.c	rcu: Add __rcu_pending tracing to hierarchical RCU	2009-04-14 11:33:43 +02:00
rcutree.h	kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies	2009-04-03 12:23:03 +02:00
rcutree_trace.c	rcu: Add __rcu_pending tracing to hierarchical RCU	2009-04-14 11:33:43 +02:00
relay.c	Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-04-05 11:04:19 -07:00
res_counter.c	memcg: memory cgroup resource counters for hierarchy	2009-01-08 08:31:05 -08:00
resource.c	Remove 'recurse into child resources' logic from 'reserve_region_with_split()'	2009-04-18 21:44:24 -07:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c	trivial: fix ETIMEOUT -> ETIMEDOUT typos	2009-06-12 18:01:50 +02:00
rtmutex.h
rtmutex_common.h	rt_mutex: add proxy lock routines	2009-04-06 11:14:02 +02:00
rwsem.c
sched.c	sched: export kick_process	2009-06-12 22:27:01 +09:30
sched_clock.c	sched: Fix fallback sched_clock()'s offset when using jiffies	2009-05-09 10:08:19 +02:00
sched_cpupri.c	sched: use slab in cpupri_init()	2009-06-11 19:27:12 +03:00
sched_cpupri.h	cpumask: remove cpumask_t from core	2009-03-30 22:05:17 +10:30
sched_debug.c	sched: remove unused fields from struct rq	2009-03-24 23:16:51 +01:00
sched_fair.c	sched: remove redundant hierarchy walk in check_preempt_wakeup	2009-04-09 08:19:08 +02:00
sched_features.h	Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-03-30 17:17:35 -07:00
sched_idletask.c	sched, timers: move calc_load() to scheduler	2009-05-15 15:32:45 +02:00
sched_rt.c	cpumask: alloc zeroed cpumask for static cpumask_var_ts	2009-06-09 22:30:27 +09:30
sched_stats.h	sched: remove unused fields from struct rq	2009-03-24 23:16:51 +01:00
seccomp.c	x86-64: seccomp: fix 32/64 syscall hole	2009-03-02 15:41:30 -08:00
semaphore.c
signal.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6	2009-06-11 10:01:41 -07:00
slow-work.c	slow_work_thread() should do the exclusive wait	2009-06-11 11:26:38 -07:00
smp.c	cpumask: alloc zeroed cpumask for static cpumask_var_ts	2009-06-09 22:30:27 +09:30
softirq.c	Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-06-10 19:53:40 -07:00
softlockup.c	softlockup: decouple hung tasks check from softlockup detection	2009-01-16 14:06:04 +01:00
spinlock.c	Allow rwlocks to re-enable interrupts	2009-04-02 19:05:11 -07:00
srcu.c
stacktrace.c	stacktrace: provide save_stack_trace_tsk() weak alias	2008-12-25 11:44:43 +01:00
stop_machine.c	cpumask: remove cpumask_t from core	2009-03-30 22:05:17 +10:30
sys.c	Merge branch 'linus' into perfcounters/core	2009-04-29 14:47:05 +02:00
sys_ni.c	Merge commit 'v2.6.29-rc2' into perfcounters/core	2009-01-21 16:37:27 +01:00
sysctl.c	Merge branch 'perfcounters-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-06-11 14:01:07 -07:00
sysctl_check.c	net: add ARP notify option for devices	2009-02-01 01:04:33 -08:00
taskstats.c	cpumask: convert rest of files in kernel/	2009-01-01 10:12:28 +10:30
test_kprobes.c	kprobes: add tests for register_kprobes	2009-01-06 15:59:20 -08:00
time.c	[CVE-2009-0029] System call wrappers part 01	2009-01-14 14:15:18 +01:00
timeconst.pl
timer.c	Merge branch 'linus' into x86/mce3	2009-06-11 23:31:52 +02:00
tracepoint.c	tracepoints: dont update zero-sized tracepoint sections	2009-03-18 19:55:00 +01:00
tsacct.c	Fix fixpoint divide exception in acct_update_integrals	2009-03-09 08:13:35 -07:00
uid16.c	[CVE-2009-0029] System call wrappers part 19	2009-01-14 14:15:26 +01:00
up.c	smp_call_function_single(): be slightly less stupid, fix #2	2009-01-12 16:04:37 +01:00
user.c	Merge branch 'master' into next	2009-03-24 10:52:46 +11:00
user_namespace.c	Fix recursive lock in free_uid()/free_user_ns()	2009-02-27 16:26:21 -08:00
utsname.c
utsname_sysctl.c	proc_sysctl: use CONFIG_PROC_SYSCTL around ipc and utsname proc_handlers	2009-04-02 19:05:01 -07:00
wait.c	wait: don't use __wake_up_common()	2009-04-14 17:17:16 +02:00
workqueue.c	ftrace, workqueuetrace: make workqueue tracepoints use TRACE_EVENT macro	2009-06-02 01:10:40 +02:00