[tip:perfcounters/urgent] perf_counters: Increase paranoia level

tip-bot for Ingo Molnar
2009-08-28T11:52:39Z

Commit-ID: 6bb56347f5162d1a7cb1dc461023360781ecd4c0
Gitweb: http://git.kernel.org/tip/6bb56347f5162d1a7cb1dc461023360781ecd4c0
Author: Ingo Molnar <mingo@elte.hu>
AuthorDate: Fri, 28 Aug 2009 13:44:53 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 28 Aug 2009 13:44:53 +0200

perf_counters: Increase paranoia level

Per-cpu counters are an ASLR information leak as they show
the execution other tasks do. Increase the paranoia level
to 1, which disallows per-cpu counters. (they still allow
counting/profiling of own tasks - and admin can profile
everything.)

Acked-by: 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 | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index f274e19..7d4bb83 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -50,7 +50,7 @@ static atomic_t nr_task_counters __read_mostly;
* 1 - disallow cpu counters to unpriv
* 2 - disallow kernel profiling to unpriv
*/
-int sysctl_perf_counter_paranoid __read_mostly;
+int sysctl_perf_counter_paranoid __read_mostly = 1;

static inline bool perf_paranoid_cpu(void)
{