Re: [PATCH v2] video: fbdev: udlfb: Fix buffer on stack

Re: [PATCH v2] video: fbdev: udlfb: Fix buffer on stack

[Bartlomiej Zolnierkiewicz]

On Monday, April 24, 2017 11:13:49 AM Maksim Salau wrote:
> Allocate buffers on HEAP instead of STACK for local array
> that is to be sent using usb_control_msg().
> 
> Signed-off-by: Maksim Salau <maksim.salau@gmail.com>

Patch queued for 4.12, thanks.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

[PATCH v2] video: fbdev: udlfb: Fix buffer on stack

[Maksim Salau]

Allocate buffers on HEAP instead of STACK for local array
that is to be sent using usb_control_msg().

Signed-off-by: Maksim Salau <maksim.salau@gmail.com>
---
 Changes in v2:
   declared set_def_chn as 'static const' to avoid double copying;
   replaced allocation and copying with a single call to kmemdup.

 drivers/video/fbdev/udlfb.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c
index e9c2f7b..6a3c353 100644
--- a/drivers/video/fbdev/udlfb.c
+++ b/drivers/video/fbdev/udlfb.c
@@ -1487,15 +1487,25 @@ static struct device_attribute fb_device_attrs[] = {
 static int dlfb_select_std_channel(struct dlfb_data *dev)
 {
 	int ret;
-	u8 set_def_chn[] = {	   0x57, 0xCD, 0xDC, 0xA7,
+	void *buf;
+	static const u8 set_def_chn[] = {
+				0x57, 0xCD, 0xDC, 0xA7,
 				0x1C, 0x88, 0x5E, 0x15,
 				0x60, 0xFE, 0xC6, 0x97,
 				0x16, 0x3D, 0x47, 0xF2  };
 
+	buf = kmemdup(set_def_chn, sizeof(set_def_chn), GFP_KERNEL);
+
+	if (!buf)
+		return -ENOMEM;
+
 	ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
 			NR_USB_REQUEST_CHANNEL,
 			(USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
-			set_def_chn, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT);
+			buf, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT);
+
+	kfree(buf);
+
 	return ret;
 }
 
-- 
2.9.3