Re: [PATCH] staging: gdm724x: Fix DMA from stack

From: Dan Carpenter
Date: Tue Feb 09 2021 - 14:50:19 EST


On Tue, Feb 09, 2021 at 08:24:15PM +0530, ameynarkhede03@xxxxxxxxx wrote:
> From: Amey Narkhede <ameynarkhede03@xxxxxxxxx>
>
> Stack allocated buffers cannot be used for DMA
> on all architectures so allocate usbdev buffer
> using kmalloc().
>
> Signed-off-by: Amey Narkhede <ameynarkhede03@xxxxxxxxx>
> ---
> drivers/staging/gdm724x/gdm_usb.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/staging/gdm724x/gdm_usb.c b/drivers/staging/gdm724x/gdm_usb.c
> index dc4da66c3..50dc463d4 100644
> --- a/drivers/staging/gdm724x/gdm_usb.c
> +++ b/drivers/staging/gdm724x/gdm_usb.c
> @@ -56,7 +56,7 @@ static int gdm_usb_recv(void *priv_dev,
>
> static int request_mac_address(struct lte_udev *udev)
> {
> - u8 buf[16] = {0,};
> + u8 *buf;
> struct hci_packet *hci = (struct hci_packet *)buf;
> struct usb_device *usbdev = udev->usbdev;
> int actual;
> @@ -66,6 +66,10 @@ static int request_mac_address(struct lte_udev *udev)
> hci->len = gdm_cpu_to_dev16(udev->gdm_ed, 1);
> hci->data[0] = MAC_ADDRESS;
>
> + buf = kmalloc(16, GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> ret = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 2), buf, 5,
> &actual, 1000);


You need to add a kfree() as well.

regards,
dan carpenter