3.2.87-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx> commit f9c85ee67164b37f9296eab3b754e543e4e96a1c upstream. Reported as a Kaffeine bug: https://bugs.kde.org/show_bug.cgi?id=375811 The USB control messages require DMA to work. We cannot pass a stack-allocated buffer, as it is not warranted that the stack would be into a DMA enabled area. On Kernel 4.9, the default is to not accept DMA on stack anymore on x86 architecture. On other architectures, this has been a requirement since Kernel 2.2. So, after this patch, this driver should likely work fine on all archs. Tested with USB ID 2040:5510: Hauppauge Windham Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx> [bwh: Backported to 3.2: - s/sms_msg_hdr/SmsMsgHdr_ST/ - Adjust filename, context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- drivers/media/dvb/siano/smsusb.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) --- a/drivers/media/dvb/siano/smsusb.c +++ b/drivers/media/dvb/siano/smsusb.c @@ -181,11 +181,20 @@ static int smsusb_start_streaming(struct static int smsusb_sendrequest(void *context, void *buffer, size_t size) { struct smsusb_device_t *dev = (struct smsusb_device_t *) context; - int dummy; + struct SmsMsgHdr_ST *phdr; + int dummy, ret; - smsendian_handle_message_header((struct SmsMsgHdr_ST *)buffer); - return usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 2), - buffer, size, &dummy, 1000); + phdr = kmalloc(size, GFP_KERNEL); + if (!phdr) + return -ENOMEM; + memcpy(phdr, buffer, size); + + smsendian_handle_message_header((struct SmsMsgHdr_ST *)phdr); + ret = usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 2), + phdr, size, &dummy, 1000); + + kfree(phdr); + return ret; } static char *smsusb1_fw_lkup[] = {