Commit 96f3eda6 authored by Kan Liang's avatar Kan Liang Committed by Ingo Molnar

perf/x86/intel: Fix static checker warning in lbr enable

Commit deb27519 ("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: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarKan Liang <kan.liang@intel.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: deb27519 ("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.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 02386c35
...@@ -151,8 +151,9 @@ static void __intel_pmu_lbr_enable(bool pmi) ...@@ -151,8 +151,9 @@ static void __intel_pmu_lbr_enable(bool pmi)
* No need to reprogram LBR_SELECT in a PMI, as it * No need to reprogram LBR_SELECT in a PMI, as it
* did not change. * did not change.
*/ */
lbr_select = cpuc->lbr_sel->config; if (cpuc->lbr_sel)
if (cpuc->lbr_sel && !pmi) lbr_select = cpuc->lbr_sel->config;
if (!pmi)
wrmsrl(MSR_LBR_SELECT, lbr_select); wrmsrl(MSR_LBR_SELECT, lbr_select);
rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl); rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
......
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