[GIT PULL] perf fix

From: Ingo Molnar
Date: Tue May 10 2016 - 07:43:52 EST


Linus,

Please pull the latest perf-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf-urgent-for-linus

# HEAD: 93193230f7b8bd484d1749f4044d1214d521c804 perf/core: Change the default paranoia level to 2

Bump up the default perf paranoia level to 2 because otherwise perf can be used by
local users to defeat KASLR, amongst other things.

Thanks,

Ingo

------------------>
Andy Lutomirski (1):
perf/core: Change the default paranoia level to 2


Documentation/sysctl/kernel.txt | 2 +-
kernel/events/core.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 57653a44b128..fcddfd5ded99 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -645,7 +645,7 @@ allowed to execute.
perf_event_paranoid:

Controls use of the performance events system by unprivileged
-users (without CAP_SYS_ADMIN). The default value is 1.
+users (without CAP_SYS_ADMIN). The default value is 2.

-1: Allow use of (almost) all events by all users
>=0: Disallow raw tracepoint access by users without CAP_IOC_LOCK
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4e2ebf6f2f1f..c0ded2416615 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -351,7 +351,7 @@ static struct srcu_struct pmus_srcu;
* 1 - disallow cpu events for unpriv
* 2 - disallow kernel profiling for unpriv
*/
-int sysctl_perf_event_paranoid __read_mostly = 1;
+int sysctl_perf_event_paranoid __read_mostly = 2;

/* Minimum for 512 kiB + 1 user control page */
int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */