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/ce6230.c | 11 +++++++++--
1 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/media/dvb/dvb-usb/ce6230.c b/drivers/media/dvb/dvb-usb/ce6230.c
index 3df2045..6d1a304 100644
--- a/drivers/media/dvb/dvb-usb/ce6230.c
+++ b/drivers/media/dvb/dvb-usb/ce6230.c
@@ -39,7 +39,7 @@ static int ce6230_rw_udev(struct usb_device *udev, struct req_t *req)
u8 requesttype;
u16 value;
u16 index;
- u8 buf[req->data_len];
+ u8 *buf;
request = req->cmd;
value = req->value;
@@ -62,6 +62,12 @@ static int ce6230_rw_udev(struct usb_device *udev, struct req_t *req)
goto error;
}
+ buf = kmalloc(req->data_len, GFP_KERNEL);
+ if (!buf) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
if (requesttype == (USB_TYPE_VENDOR | USB_DIR_OUT)) {
/* write */
memcpy(buf, req->data, req->data_len);
@@ -74,7 +80,7 @@ static int ce6230_rw_udev(struct usb_device *udev, struct req_t *req)
msleep(1); /* avoid I2C errors */
ret = usb_control_msg(udev, pipe, request, requesttype, value, index,
- buf, sizeof(buf), CE6230_USB_TIMEOUT);
+ buf, req->data_len, CE6230_USB_TIMEOUT);
ce6230_debug_dump(request, requesttype, value, index, buf,
req->data_len, deb_xfer);
@@ -88,6 +94,7 @@ static int ce6230_rw_udev(struct usb_device *udev, struct req_t *req)
if (!ret && requesttype == (USB_TYPE_VENDOR | USB_DIR_IN))
memcpy(req->data, buf, req->data_len);
+ kfree(buf);
error:
return ret;
}
--
1.7.4.1
--
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