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

[Amey Narkhede]

On 21/02/09 06:40PM, Greg KH wrote:
> 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;
> > +
>
> This is great, but you just added a build warning, which implies that
> the patch is incorrect.
>
> You also have a memory leak here, which is not acceptable :(
>
> thanks,
>
> greg k-h
Apologoes. I'll send v2.

Thanks,
Amey

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