Patchwork [040/115] perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNEL

login
register
mail settings
Submitter Luis Henriques
Date May 20, 2013, 10:50 a.m.
Message ID <1369047116-9378-41-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/244928/
State New
Headers show

Comments

Luis Henriques - May 20, 2013, 10:50 a.m.
3.5.7.13 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Zijlstra <a.p.zijlstra@chello.nl>

commit 7cc23cd6c0c7d7f4bee057607e7ce01568925717 upstream.

We should always have proper privileges when requesting kernel
data.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/20130503121256.230745028@chello.nl
[ Fix build error reported by fengguang.wu@intel.com, propagate error code back. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/n/tip-v0x9ky3ahzr6nm3c6ilwrili@git.kernel.org
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 arch/x86/kernel/cpu/perf_event_intel_lbr.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

Patch

diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index 62a93a4..fd1a099 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -310,7 +310,7 @@  void intel_pmu_lbr_read(void)
  * - in case there is no HW filter
  * - in case the HW filter has errata or limitations
  */
-static void intel_pmu_setup_sw_lbr_filter(struct perf_event *event)
+static int intel_pmu_setup_sw_lbr_filter(struct perf_event *event)
 {
 	u64 br_type = event->attr.branch_sample_type;
 	int mask = 0;
@@ -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 */
 
@@ -339,6 +342,8 @@  static void intel_pmu_setup_sw_lbr_filter(struct perf_event *event)
 	 * be used by fixup code for some CPU
 	 */
 	event->hw.branch_reg.reg = mask;
+
+	return 0;
 }
 
 /*
@@ -386,7 +391,9 @@  int intel_pmu_setup_lbr_filter(struct perf_event *event)
 	/*
 	 * setup SW LBR filter
 	 */
-	intel_pmu_setup_sw_lbr_filter(event);
+	ret = intel_pmu_setup_sw_lbr_filter(event);
+	if (ret)
+		return ret;
 
 	/*
 	 * setup HW LBR filter, if any