On Thu, Jan 19, 2023 at 08:31:19AM +0000, Yuan Can wrote:
> As the dma_alloc_coherent may return NULL, the return value needs to be
> checked to avoid NULL poineter dereference.
>
> Fixes: 33aa8d45a4fe ("staging: emxx_udc: Add Emma Mobile USB Gadget driver")
> Signed-off-by: Yuan Can <yuancan@xxxxxxxxxx>
> ---
> changes in v2:
> - do the null pointer check right before the memcpy().
> changes in v3:
> - do the null pointer check right after the dma_alloc_coherent().
>
> drivers/staging/emxx_udc/emxx_udc.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
I am no longer associated with Renesas, as I was when the patch
that added this problem was accepted.
But, FWIIW,
Reviewed-by: Simon Horman <horms@xxxxxxxxxxxx>
>
> diff --git a/drivers/staging/emxx_udc/emxx_udc.c b/drivers/staging/emxx_udc/emxx_udc.c
> index b4e19174bef2..f9765841c4aa 100644
> --- a/drivers/staging/emxx_udc/emxx_udc.c
> +++ b/drivers/staging/emxx_udc/emxx_udc.c
> @@ -2587,10 +2587,15 @@ static int nbu2ss_ep_queue(struct usb_ep *_ep,
> req->unaligned = false;
>
> if (req->unaligned) {
> - if (!ep->virt_buf)
> + if (!ep->virt_buf) {
> ep->virt_buf = dma_alloc_coherent(udc->dev, PAGE_SIZE,
> &ep->phys_buf,
> GFP_ATOMIC | GFP_DMA);
> + if (!ep->virt_buf) {
> + spin_unlock_irqrestore(&udc->lock, flags);
> + return -ENOMEM;
> + }
> + }
> if (ep->epnum > 0) {
> if (ep->direct == USB_DIR_IN)
> memcpy(ep->virt_buf, req->req.buf,
> --
> 2.17.1
>
