usb_control_msg initiates (and waits for completion of) a dma transfer using the supplied buffer. That buffer thus has to be seperately allocated on the heap. In lib/dma_debug.c the function check_for_stack even warns about it: WARNING: at lib/dma-debug.c:866 check_for_stack Signed-off-by: Florian Mickler <florian@xxxxxxxxxxx> Acked-by: Antti Palosaari <crope@xxxxxx> Reviewed-by: Antti Palosaari <crope@xxxxxx> Tested-by: Antti Palosaari <crope@xxxxxx> --- drivers/media/dvb/dvb-usb/ec168.c | 18 +++++++++++++++--- 1 files changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/media/dvb/dvb-usb/ec168.c b/drivers/media/dvb/dvb-usb/ec168.c index 52f5d4f..1ba3e5d 100644 --- a/drivers/media/dvb/dvb-usb/ec168.c +++ b/drivers/media/dvb/dvb-usb/ec168.c @@ -36,7 +36,9 @@ static int ec168_rw_udev(struct usb_device *udev, struct ec168_req *req) int ret; unsigned int pipe; u8 request, requesttype; - u8 buf[req->size]; + u8 *buf; + + switch (req->cmd) { case DOWNLOAD_FIRMWARE: @@ -72,6 +74,12 @@ static int ec168_rw_udev(struct usb_device *udev, struct ec168_req *req) goto error; } + buf = kmalloc(req->size, GFP_KERNEL); + if (!buf) { + ret = -ENOMEM; + goto error; + } + if (requesttype == (USB_TYPE_VENDOR | USB_DIR_OUT)) { /* write */ memcpy(buf, req->data, req->size); @@ -84,13 +92,13 @@ static int ec168_rw_udev(struct usb_device *udev, struct ec168_req *req) msleep(1); /* avoid I2C errors */ ret = usb_control_msg(udev, pipe, request, requesttype, req->value, - req->index, buf, sizeof(buf), EC168_USB_TIMEOUT); + req->index, buf, req->size, EC168_USB_TIMEOUT); ec168_debug_dump(request, requesttype, req->value, req->index, buf, req->size, deb_xfer); if (ret < 0) - goto error; + goto err_dealloc; else ret = 0; @@ -98,7 +106,11 @@ static int ec168_rw_udev(struct usb_device *udev, struct ec168_req *req) if (!ret && requesttype == (USB_TYPE_VENDOR | USB_DIR_IN)) memcpy(req->data, buf, req->size); + kfree(buf); return ret; + +err_dealloc: + kfree(buf); error: deb_info("%s: failed:%d\n", __func__, ret); return ret; -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html