From: Ben Hutchings
> Sent: 04 February 2017 16:57
> Allocating USB buffers on the stack is not portable, and no longer
> works on x86_64 (with VMAP_STACK enabled as per default).
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Ben Hutchings <[email protected]>
> ---
> drivers/net/usb/rtl8150.c | 34 +++++++++++++++++++++++++++-------
> 1 file changed, 27 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/usb/rtl8150.c b/drivers/net/usb/rtl8150.c
> index 95b7bd0d7abc..c81c79110cef 100644
> --- a/drivers/net/usb/rtl8150.c
> +++ b/drivers/net/usb/rtl8150.c
> @@ -155,16 +155,36 @@ static const char driver_name [] = "rtl8150";
> */
> static int get_registers(rtl8150_t * dev, u16 indx, u16 size, void *data)
> {
> - return usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
> - RTL8150_REQ_GET_REGS, RTL8150_REQT_READ,
> - indx, 0, data, size, 500);
> + void *buf;
> + int ret;
> +
> + buf = kmalloc(size, GFP_NOIO);
> + if (!buf)
> + return -ENOMEM;
> +
> + ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
> + RTL8150_REQ_GET_REGS, RTL8150_REQT_READ,
> + indx, 0, buf, size, 500);
> + if (ret > 0 && ret <= size)
> + memcpy(data, buf, ret);
If ret > size something is horridly wrong.
Silently not updating the callers buffer at all cannot be right.
> + kfree(buf);
> + return ret;
I can't help feeling that it would be better to add a wrapper to
usb_control_msg() that does the kmalloc() and memcpy()s and
drop that into all the call sites.
David
