[PATCH 4.11 48/84] perf/x86/intel/uncore: Fix wrong box pointer check

Greg Kroah-Hartman
2017-07-03T13:35:28Z

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

commit 80c65fdb4c6920e332a9781a3de5877594b07522 upstream.

Should not init a NULL box. It will cause system crash.
The issue looks like caused by a typo.

This was not noticed because there is no NULL box. Also, for most
boxes, they are enabled by default. The init code is not critical.

Fixes: fff4b87e594a ("perf/x86/intel/uncore: Make package handling more robust")
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170629190926.2456-1-kan.liang@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/events/intel/uncore.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -1170,7 +1170,7 @@ static int uncore_event_cpu_online(unsig
pmu = type->pmus;
for (i = 0; i < type->num_boxes; i++, pmu++) {
box = pmu->boxes[pkg];
- if (!box && atomic_inc_return(&box->refcnt) == 1)
+ if (box && atomic_inc_return(&box->refcnt) == 1)
uncore_box_init(box);
}
}