Re: [PATCH] usb: gadget: udc: add return value check of kzalloc in mv_udc_probe

Dongliang Mu
2023-02-24T11:08:15Z

On Fri, Feb 24, 2023 at 5:28 PM void0red <void0red@gmail.com> wrote:
>
> From: Kang Chen <void0red@gmail.com>
>
> Even an 8-byte kzalloc will fail when we don't have enough memory,
> so we need a nullptr check and do the cleanup when it fails.
>
> Reported-by: eriri <1527030098@qq.com>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217081
>
> Signed-off-by: Kang Chen <void0red@gmail.com>
> ---
> drivers/usb/gadget/udc/mv_udc_core.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/usb/gadget/udc/mv_udc_core.c b/drivers/usb/gadget/udc/mv_udc_core.c
> index b397f3a84..6dd6d52de 100644
> --- a/drivers/usb/gadget/udc/mv_udc_core.c
> +++ b/drivers/usb/gadget/udc/mv_udc_core.c
> @@ -2230,6 +2230,10 @@ static int mv_udc_probe(struct platform_device *pdev)
>
> /* allocate a small amount of memory to get valid address */
> udc->status_req->req.buf = kzalloc(8, GFP_KERNEL);

Hi Kang and gregkh,

I think there is a memory leak in this kzalloc. It seems there is no
deallocation for this allocated object.

As the surrounding allocation statements suggest,
we should turn kzalloc to devm_kzalloc.

> + if (!udc->status_req->req.buf) {
> + retval = -ENOMEM;
> + goto err_destroy_dma;
> + }
> udc->status_req->req.dma = DMA_ADDR_INVALID;
>
> udc->resume_state = USB_STATE_NOTATTACHED;
> --
> 2.34.1
>