From 96f3eda67fcf2598e9d2794398e0e7ab35138ea6 Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Mon, 14 Sep 2015 10:14:07 -0400 Subject: [PATCH] perf/x86/intel: Fix static checker warning in lbr enable 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) Fix the warning. Reported-by: Dan Carpenter Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: deb27519bf1f ("perf/x86/intel: Fix LBR callstack issue caused by FREEZE_LBRS_ON_PMI") Link: http://lkml.kernel.org/r/1442240047-48149-1-git-send-email-kan.liang@intel.com Signed-off-by: Ingo Molnar --- 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 a1d07c71d3b6..ad0b8b0490a0 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);