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[PATCH 1/1] perf/x86/intel: Fix static checker warning in lbr enable

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From: Kan Liang <kan.liang@intel.com>

The commit deb27519bf1f ("perf/x86/intel: Fix LBR callstack issue caused
by FREEZE_LBRS_ON_PMI") leads to the following Smatch complaint.
warn: variable dereferenced before check 'cpuc->lbr_sel' (see line 154)

This patch is to fix this warning.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
---
 arch/x86/kernel/cpu/perf_event_intel_lbr.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index a1d07c7..ad0b8b0 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -151,8 +151,9 @@ static void __intel_pmu_lbr_enable(bool pmi)
 	 * No need to reprogram LBR_SELECT in a PMI, as it
 	 * did not change.
 	 */
-	lbr_select = cpuc->lbr_sel->config;
-	if (cpuc->lbr_sel && !pmi)
+	if (cpuc->lbr_sel)
+		lbr_select = cpuc->lbr_sel->config;
+	if (!pmi)
 		wrmsrl(MSR_LBR_SELECT, lbr_select);
 
 	rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
-- 
1.8.3.1

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[PATCH 1/1] perf/x86/intel: Fix static checker warning in lbr enable kan.liang@intel.com - 2015-09-14 23:40 +0200
  [tip:perf/core] perf/x86/intel:   Fix static checker warning in lbr enable tip-bot for Kan Liang <tipbot@zytor.com> - 2015-09-18 11:00 +0200

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