[PATCH 2/5] perf/x86/uncore: Fix potential NULL pointer in uncore_get_alias_name

kan.liang
2022-11-29T19:10:55Z

The current code assumes that the discovery table provides valid
box_ids for the normal units. It's not the case anymore since some units
in the discovery table are broken on some SPR variants.

Factor out uncore_get_box_id(). Check the existence of the type->box_ids
before using it. If it's not available, use pmu_idx.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
arch/x86/events/intel/uncore.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index 8caf253be1de..d63be6d1224e 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -857,6 +857,12 @@ static const struct attribute_group uncore_pmu_attr_group = {
.attrs = uncore_pmu_attrs,
};

+static inline int uncore_get_box_id(struct intel_uncore_type *type,
+ struct intel_uncore_pmu *pmu)
+{
+ return type->box_ids ? type->box_ids[pmu->pmu_idx] : pmu->pmu_idx;
+}
+
void uncore_get_alias_name(char *pmu_name, struct intel_uncore_pmu *pmu)
{
struct intel_uncore_type *type = pmu->type;
@@ -865,7 +871,7 @@ void uncore_get_alias_name(char *pmu_name, struct intel_uncore_pmu *pmu)
sprintf(pmu_name, "uncore_type_%u", type->type_id);
else {
sprintf(pmu_name, "uncore_type_%u_%d",
- type->type_id, type->box_ids[pmu->pmu_idx]);
+ type->type_id, uncore_get_box_id(type, pmu));
}
}

@@ -892,7 +898,7 @@ static void uncore_get_pmu_name(struct intel_uncore_pmu *pmu)
* Use the box ID from the discovery table if applicable.
*/
sprintf(pmu->name, "uncore_%s_%d", type->name,
- type->box_ids ? type->box_ids[pmu->pmu_idx] : pmu->pmu_idx);
+ uncore_get_box_id(type, pmu));
}
}

--
2.35.1