Commit-ID: 96f3eda67fcf2598e9d2794398e0e7ab35138ea6
Gitweb: http://git.kernel.org/tip/96f3eda67fcf2598e9d2794398e0e7ab35138ea6
Author: Kan Liang <kan.li...@intel.com>
AuthorDate: Mon, 14 Sep 2015 10:14:07 -0400
Committer: Ingo Molnar <mi...@kernel.org>
CommitDate: Fri, 18 Sep 2015 09:24:57 +0200
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 <dan.carpen...@oracle.com>
Signed-off-by: Kan Liang <kan.li...@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
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.li...@intel.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
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);
--
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