Re: [PATCH] nvdimm: fix possible null-ptr-deref in nd_dax_probe()

[Ira Weiny <ira.weiny@intel.com>]

Yi Yang wrote:
> It will cause null-ptr-deref when nd_dax_alloc() returns NULL, fix it by
> add check for nd_dax_alloc().

Was this found with a real workload or just by inspection?

Ira

> 
> Fixes: c5ed9268643c ("libnvdimm, dax: autodetect support")
> Signed-off-by: Yi Yang <yiyang13@huawei.com>
> ---
>  drivers/nvdimm/dax_devs.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/nvdimm/dax_devs.c b/drivers/nvdimm/dax_devs.c
> index 6b4922de3047..70a7e401f90d 100644
> --- a/drivers/nvdimm/dax_devs.c
> +++ b/drivers/nvdimm/dax_devs.c
> @@ -106,6 +106,10 @@ int nd_dax_probe(struct device *dev, struct nd_namespace_common *ndns)
>  
>  	nvdimm_bus_lock(&ndns->dev);
>  	nd_dax = nd_dax_alloc(nd_region);
> +	if (!nd_dax) {
> +		nvdimm_bus_unlock(&ndns->dev);
> +		return -ENOMEM;
> +	}
>  	nd_pfn = &nd_dax->nd_pfn;
>  	dax_dev = nd_pfn_devinit(nd_pfn, ndns);
>  	nvdimm_bus_unlock(&ndns->dev);
> -- 
> 2.25.1
> 
>