Re: [PATCH] drivers: nvdimm: fix dereference after free

From: Jeff Moyer
Date: Thu Aug 17 2023 - 10:27:17 EST


Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx> writes:

> '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'.
>
> Co-developed-by: Ivanov Mikhail <ivanov.mikhail1@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
> ---
> drivers/nvdimm/nd_perf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/nvdimm/nd_perf.c b/drivers/nvdimm/nd_perf.c
> index 14881c4e0..2b6dc80d8 100644
> --- a/drivers/nvdimm/nd_perf.c
> +++ b/drivers/nvdimm/nd_perf.c
> @@ -307,10 +307,10 @@ 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;
> }
>
> pr_info("%s NVDIMM performance monitor support registered\n",

Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx>