[tip:perfcounters/core] perf_counter: Introduce new (non-)paranoia level to allow raw tracepoint access

tip-bot for Ingo Molnar
2009-09-02T19:52:25Z

Commit-ID: 5380c1056d267eff49854c1fa03399bfe761da1e
Gitweb: http://git.kernel.org/tip/5380c1056d267eff49854c1fa03399bfe761da1e
Author: Ingo Molnar <mingo@elte.hu>
AuthorDate: Wed, 2 Sep 2009 21:46:00 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 2 Sep 2009 21:47:06 +0200

perf_counter: Introduce new (non-)paranoia level to allow raw tracepoint access

I want to sample inherited tracepoint workloads as a normal
user and the CAP_SYS_ADMIN check prevents me from doing that
right now.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
kernel/perf_counter.c | 13 ++++++++++---
1 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index d988dfb..53ca946 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -46,12 +46,18 @@ static atomic_t nr_task_counters __read_mostly;

/*
* perf counter paranoia level:
- * 0 - not paranoid
- * 1 - disallow cpu counters to unpriv
- * 2 - disallow kernel profiling to unpriv
+ * -1 - not paranoid at all
+ * 0 - disallow raw tracepoint access for unpriv
+ * 1 - disallow cpu counters for unpriv
+ * 2 - disallow kernel profiling for unpriv
*/
int sysctl_perf_counter_paranoid __read_mostly = 1;

+static inline bool perf_paranoid_tracepoint_raw(void)
+{
+ return sysctl_perf_counter_paranoid > -1;
+}
+
static inline bool perf_paranoid_cpu(void)
{
return sysctl_perf_counter_paranoid > 0;
@@ -3971,6 +3977,7 @@ static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
* have these.
*/
if ((counter->attr.sample_type & PERF_SAMPLE_RAW) &&
+ && perf_paranoid_tracepoint_raw() &&
!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);