Frederic Weisbecker 444a2a3bcd tracing, perf_events: Protect the buffer from recursion in perf ... While tracing using events with perf, if one enables the lockdep:lock_acquire event, it will infect every other perf trace events. Basically, you can enable whatever set of trace events through perf but if this event is part of the set, the only result we can get is a long list of lock_acquire events of rcu read lock, and only that. This is because of a recursion inside perf. 1) When a trace event is triggered, it will fill a per cpu buffer and submit it to perf. 2) Perf will commit this event but will also protect some data using rcu_read_lock 3) A recursion appears: rcu_read_lock triggers a lock_acquire event that will fill the per cpu event and then submit the buffer to perf. 4) Perf detects a recursion and ignores it 5) Perf continues its work on the previous event, but its buffer has been overwritten by the lock_acquire event, it has then been turned into a lock_acquire event of rcu read lock Such scenario also happens with lock_release with rcu_read_unlock(). We could turn the rcu_read_lock() into __rcu_read_lock() to drop the lock debugging from perf fast path, but that would make us lose the rcu debugging and that doesn't prevent from other possible kind of recursion from perf in the future. This patch adds a recursion protection based on a counter on the perf trace per cpu buffers to solve the problem. -v2: Fixed lost whitespace, added reviewed-by tag Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Jason Baron <jbaron@redhat.com> LKML-Reference: <1257477185-7838-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>		2009-11-08 10:31:42 +01:00
..
gcov	microblaze: Enable GCOV_PROFILE_ALL	2009-09-21 14:29:21 +02:00
irq	headers: remove sched.h from interrupt.h	2009-10-11 11:20:58 -07:00
power	headers: utsname.h redux	2009-09-23 18:13:10 -07:00
time	headers: remove sched.h from interrupt.h	2009-10-11 11:20:58 -07:00
trace	tracing, perf_events: Protect the buffer from recursion in perf	2009-11-08 10:31:42 +01:00
.gitignore
acct.c	bsdacct: switch credentials for writing to the accounting file	2009-08-24 11:33:40 +10:00
async.c
audit.c	Audit: send signal info if selinux is disabled	2009-09-24 03:50:26 -04:00
audit.h
audit_tree.c
audit_watch.c	Audit: reorganize struct audit_watch to save 8 bytes	2009-09-24 03:50:25 -04:00
auditfilter.c
auditsc.c	Audit: rearrange audit_context to save 16 bytes per struct	2009-09-24 03:50:26 -04:00
backtracetest.c
bounds.c
capability.c
cgroup.c	cgroup: catch bad css refcnt at css_put	2009-10-01 16:11:12 -07:00
cgroup_freezer.c	cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time	2009-09-24 07:20:58 -07:00
compat.c
configs.c
cpu.c	Merge branch 'x86-pat-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-09-15 09:19:38 -07:00
cpuset.c	cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time	2009-09-24 07:20:58 -07:00
cred-internals.h
cred.c	creds_are_invalid() needs to be exported for use by modules:	2009-09-23 11:02:26 -07:00
delayacct.c	headers: taskstats_kern.h trim	2009-09-18 09:48:52 -07:00
dma.c
exec_domain.c
exit.c	Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-10-08 12:16:35 -07:00
extable.c
fork.c	Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-10-08 12:16:35 -07:00
freezer.c	sched: fix nr_uninterruptible accounting of frozen tasks really	2009-07-18 14:19:53 +02:00
futex.c	Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-10-08 12:16:35 -07:00
futex_compat.c	futex: Fix compat_futex to be same as futex for REQUEUE_PI	2009-08-10 15:41:12 +02:00
groups.c
hrtimer.c	Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-10-05 12:04:16 -07:00
hung_task.c	sysctl: remove "struct file *" argument of ->proc_handler	2009-09-24 07:21:04 -07:00
itimer.c	itimers: Add tracepoints for itimer	2009-08-29 14:10:07 +02:00
kallsyms.c	kallsyms: use new arch_is_kernel_text()	2009-09-23 07:39:30 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.preempt
kexec.c	kexec: fix omitting offset in extended crashkernel syntax	2009-07-29 19:10:34 -07:00
kfifo.c	kfifo: Use "const" definitions	2009-09-19 13:13:17 -07:00
kgdb.c
kmod.c	Revert "kmod: fix race in usermodehelper code"	2009-09-23 18:12:10 -07:00
kprobes.c	Merge commit 'v2.6.32-rc5' into perf/probes	2009-10-17 09:58:25 +02:00
ksysfs.c
kthread.c	sched: Keep kthreads at default priority	2009-09-09 17:30:06 +02:00
latencytop.c
lockdep.c	lockdep: Use cpu_clock() for lockstat	2009-10-09 15:56:44 +02:00
lockdep_internals.h	lockdep: BFS cleanup	2009-07-24 10:53:29 +02:00
lockdep_proc.c	seq_file: constify seq_operations	2009-09-23 07:39:29 -07:00
lockdep_states.h
Makefile	cgroups: move the cgroup debug subsys into cgroup.c to access internal state	2009-09-24 07:20:57 -07:00
module.c	module: fix up CONFIG_KALLSYMS=n build.	2009-10-01 16:11:11 -07:00
mutex-debug.c	headers: remove sched.h from interrupt.h	2009-10-11 11:20:58 -07:00
mutex-debug.h
mutex.c
mutex.h
notifier.c	kprobes: Fix to add __kprobes to notify_die	2009-08-30 03:08:26 +02:00
ns_cgroup.c	cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time	2009-09-24 07:20:58 -07:00
nsproxy.c
panic.c	Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-10-08 12:16:35 -07:00
params.c	param: allow whitespace as kernel parameter separator	2009-09-25 00:32:58 +09:30
perf_event.c	Merge branch 'perf/urgent' into perf/core	2009-10-20 07:51:44 +02:00
pid.c	mm: also use alloc_large_system_hash() for the PID hash table	2009-09-22 07:17:38 -07:00
pid_namespace.c	pidns: deny CLONE_PARENT|CLONE_NEWPID combination	2009-09-24 07:21:04 -07:00
pm_qos_params.c
posix-cpu-timers.c	itimers: Add tracepoints for itimer	2009-08-29 14:10:07 +02:00
posix-timers.c	time: Introduce CLOCK_REALTIME_COARSE	2009-08-21 21:43:46 +02:00
printk.c	printk: add printk_delay to make messages readable for some scenarios	2009-09-23 07:39:28 -07:00
profile.c	kernel/profile.c: Switch /proc/irq/prof_cpu_mask to seq_file	2009-09-20 20:15:40 +02:00
ptrace.c	ptrace: __ptrace_detach: do __wake_up_parent() if we reap the tracee	2009-09-24 07:20:59 -07:00
rcupdate.c	rcu: Move rcu_barrier() to rcutree	2009-10-07 08:11:20 +02:00
rcutorture.c	rcu: Clean up code to address Ingo's checkpatch feedback	2009-09-23 19:46:30 +02:00
rcutree.c	rcu: Place root rcu_node structure in separate lockdep class	2009-10-07 08:11:21 +02:00
rcutree.h	rcu: Make hot-unplugged CPU relinquish its own RCU callbacks	2009-10-07 08:11:20 +02:00
rcutree_plugin.h	rcu: Make hot-unplugged CPU relinquish its own RCU callbacks	2009-10-07 08:11:20 +02:00
rcutree_trace.c	rcu: Make hot-unplugged CPU relinquish its own RCU callbacks	2009-10-07 08:11:20 +02:00
relay.c	const: mark struct vm_struct_operations	2009-09-27 11:39:25 -07:00
res_counter.c	memcg: some modification to softlimit under hierarchical memory reclaim.	2009-10-01 16:11:13 -07:00
resource.c	walk system ram range	2009-09-23 07:39:41 -07:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c	rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock()	2009-08-06 05:50:21 +02:00
rtmutex.h
rtmutex_common.h
rwsem.c
sched.c	Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-10-14 15:25:04 -07:00
sched_clock.c	sched_clock: Fix atomicity/continuity bug by using cmpxchg64()	2009-09-30 22:56:10 +02:00
sched_cpupri.c	sched: Add new prio to cpupri before removing old prio	2009-08-02 14:26:09 +02:00
sched_cpupri.h
sched_debug.c	sched: Add new wakeup preemption mode: WAKEUP_RUNNING	2009-09-17 10:17:25 +02:00
sched_fair.c	sysctl: remove "struct file *" argument of ->proc_handler	2009-09-24 07:21:04 -07:00
sched_features.h	sched: Add new wakeup preemption mode: WAKEUP_RUNNING	2009-09-17 10:17:25 +02:00
sched_idletask.c	sched: Simplify sys_sched_rr_get_interval() system call	2009-09-21 09:53:55 +02:00
sched_rt.c	sched: Simplify sys_sched_rr_get_interval() system call	2009-09-21 09:53:55 +02:00
sched_stats.h
seccomp.c
semaphore.c
signal.c	signals: inline __fatal_signal_pending	2009-09-24 07:21:01 -07:00
slow-work.c	sysctl: remove "struct file *" argument of ->proc_handler	2009-09-24 07:21:04 -07:00
smp.c	cpumask: remove arch_send_call_function_ipi	2009-09-24 09:34:47 +09:30
softirq.c	softirq: add BLOCK_IOPOLL to softirq_to_name	2009-09-17 15:53:44 -04:00
softlockup.c	sysctl: remove "struct file *" argument of ->proc_handler	2009-09-24 07:21:04 -07:00
spinlock.c	locking: Allow arch-inlined spinlocks	2009-08-31 18:08:50 +02:00
srcu.c
stacktrace.c
stop_machine.c
sys.c	Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6	2009-09-24 07:53:22 -07:00
sys_ni.c	Merge branch 'master' of /home/davem/src/GIT/linux-2.6/	2009-09-24 15:13:11 -07:00
sysctl.c	Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6	2009-09-24 07:53:22 -07:00
sysctl_check.c
taskstats.c	genetlink: make netns aware	2009-07-12 14:03:27 -07:00
test_kprobes.c
time.c	time: Prevent 32 bit overflow with set_normalized_timespec()	2009-09-15 10:17:30 +02:00
timeconst.pl
timer.c	Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-09-23 09:46:15 -07:00
tracepoint.c	trivial: fix typo "to to" in multiple files	2009-09-21 15:14:55 +02:00
tsacct.c
uid16.c	headers: utsname.h redux	2009-09-23 18:13:10 -07:00
up.c
user.c
user_namespace.c
utsname.c
utsname_sysctl.c	sysctl: remove "struct file *" argument of ->proc_handler	2009-09-24 07:21:04 -07:00
wait.c	locking, sched: Give waitqueue spinlocks their own lockdep classes	2009-08-10 14:43:09 +02:00
workqueue.c	workqueue: add 'flush_delayed_work()' to run and wait for delayed work	2009-10-14 15:11:35 -07:00