nvdimm: Fix dereference after free in register_nvdimm_pmu()

'nd_pmu->pmu.attr_groups' is dereferenced in function
'nvdimm_pmu_free_hotplug_memory' call after it has been freed. Because in
function 'nvdimm_pmu_free_hotplug_memory' memory pointed by the fields of
'nd_pmu->pmu.attr_groups' is deallocated it is necessary to call 'kfree'
after 'nvdimm_pmu_free_hotplug_memory'.

Fixes: 0fab1ba ("drivers/nvdimm: Add perf interface to expose nvdimm performance stats")
Co-developed-by: Ivanov Mikhail <[email protected]>
Signed-off-by: Konstantin Meskhidze <[email protected]>
Reviewed-by: Jeff Moyer <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Dave Jiang <[email protected]>

Author: BoardzMaster

drivers/nvdimm/nd_perf.c

@@ -308,8 +308,8 @@ int register_nvdimm_pmu(struct nvdimm_pmu *nd_pmu, struct platform_device *pdev)
 
 	rc = perf_pmu_register(&nd_pmu->pmu, nd_pmu->pmu.name, -1);
 	if (rc) {
-		kfree(nd_pmu->pmu.attr_groups);
 		nvdimm_pmu_free_hotplug_memory(nd_pmu);
+		kfree(nd_pmu->pmu.attr_groups);
 		return rc;
 	}