linux-kernel - Re: [PATCH] usb: gadget: udc: add return value check of kzalloc in mv_udc

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Date:   Fri, 24 Feb 2023 19:03:27 +0800
From:   Dongliang Mu <mudongliangabcd@...il.com>
To:     void0red <void0red@...il.com>
Cc:     gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] usb: gadget: udc: add return value check of kzalloc in mv_udc_probe

On Fri, Feb 24, 2023 at 5:28 PM void0red <void0red@...il.com> wrote:
>
> From: Kang Chen <void0red@...il.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@...com>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217081
>
> Signed-off-by: Kang Chen <void0red@...il.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
>