Re: [PATCH net V2] net: pds_core: Fix possible double free in error handling path

[Nelson, Shannon]

On 3/3/2024 12:49 AM, hyper wrote:
> When auxiliary_device_add() returns error and then calls
> auxiliary_device_uninit(), Callback function pdsc_auxbus_dev_release
> calls kfree(padev) to free memory. We shouldn't call kfree(padev)
> again in the error handling path.
>
> Fix this by cleaning up the redundant kfree() and putting
> the error handling back to where the errors happened.
>
> Fixes: 4569cce43bc6 ("pds_core: add auxiliary_bus devices")
> Signed-off-by: hyper <hyperlyzcs@xxxxxxxxx>

Thanks.

Reviewed-by: Shannon Nelson <shannon.nelson@xxxxxxx>


> ---
>   drivers/net/ethernet/amd/pds_core/auxbus.c | 12 ++++--------
>   1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/ethernet/amd/pds_core/auxbus.c b/drivers/net/ethernet/amd/pds_core/auxbus.c
> index 11c23a7f3172..fd1a5149c003 100644
> --- a/drivers/net/ethernet/amd/pds_core/auxbus.c
> +++ b/drivers/net/ethernet/amd/pds_core/auxbus.c
> @@ -160,23 +160,19 @@ static struct pds_auxiliary_dev *pdsc_auxbus_dev_register(struct pdsc *cf,
>          if (err < 0) {
>                  dev_warn(cf->dev, "auxiliary_device_init of %s failed: %pe\n",
>                           name, ERR_PTR(err));
> -               goto err_out;
> +               kfree(padev);
> +               return ERR_PTR(err);
>          }
>
>          err = auxiliary_device_add(aux_dev);
>          if (err) {
>                  dev_warn(cf->dev, "auxiliary_device_add of %s failed: %pe\n",
>                           name, ERR_PTR(err));
> -               goto err_out_uninit;
> +               auxiliary_device_uninit(aux_dev);
> +               return ERR_PTR(err);
>          }
>
>          return padev;
> -
> -err_out_uninit:
> -       auxiliary_device_uninit(aux_dev);
> -err_out:
> -       kfree(padev);
> -       return ERR_PTR(err);
>   }
>
>   int pdsc_auxbus_dev_del(struct pdsc *cf, struct pdsc *pf)
> --
> 2.36.1