[tip:perf/urgent] perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNEL

From: tip-bot for Peter Zijlstra
Date: Sat May 04 2013 - 04:23:21 EST


Commit-ID: 0f5c78b5f33ce940034743e5f9485fc81ad75b0f
Gitweb: http://git.kernel.org/tip/0f5c78b5f33ce940034743e5f9485fc81ad75b0f
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Fri, 3 May 2013 14:11:25 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sat, 4 May 2013 08:37:48 +0200

perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNEL

We should always have proper privileges when requesting kernel
data.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: eranian@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20130503121256.230745028@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-v0x9ky3ahzr6nm3c6ilwrili@xxxxxxxxxxxxxx
---
arch/x86/kernel/cpu/perf_event_intel_lbr.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index de341d4..0e92871 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -318,8 +318,11 @@ static void intel_pmu_setup_sw_lbr_filter(struct perf_event *event)
if (br_type & PERF_SAMPLE_BRANCH_USER)
mask |= X86_BR_USER;

- if (br_type & PERF_SAMPLE_BRANCH_KERNEL)
+ if (br_type & PERF_SAMPLE_BRANCH_KERNEL) {
+ if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
+ return -EACCES;
mask |= X86_BR_KERNEL;
+ }

/* we ignore BRANCH_HV here */

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