staging: comedi: drivers: usbduxsigma.c: fix DMA buffers on stack

This patch fixes an instance of DMA buffer on stack(being passed to
usb_control_msg)for the USB-DUXsigma Board driver. Found using smatch.

Signed-off-by: Kumar Amit Mehta <gmate.amit@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 17 insertions, 10 deletions

diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
index d066351a71b2..a728c8fc32a2 100644
--- a/drivers/staging/comedi/drivers/usbduxsigma.c
+++ b/drivers/staging/comedi/drivers/usbduxsigma.c
@@ -681,7 +681,11 @@ static void usbduxsub_ao_IsocIrq(struct urb *urb)
 static int usbduxsub_start(struct usbduxsub *usbduxsub)
 {
         int errcode = 0;
-        uint8_t local_transfer_buffer[16];
+        uint8_t *local_transfer_buffer;
+
+        local_transfer_buffer = kmalloc(16, GFP_KERNEL);
+        if (!local_transfer_buffer)
+                return -ENOMEM;
 
         /* 7f92 to zero */
         local_transfer_buffer[0] = 0;
@@ -702,19 +706,22 @@ static int usbduxsub_start(struct usbduxsub *usbduxsub)
                                   1,
                                   /* Timeout */
                                   BULK_TIMEOUT);
-        if (errcode < 0) {
+        if (errcode < 0)
                 dev_err(&usbduxsub->interface->dev,
                         "comedi_: control msg failed (start)\n");
-                return errcode;
-        }
-        return 0;
+
+        kfree(local_transfer_buffer);
+        return errcode;
 }
 
 static int usbduxsub_stop(struct usbduxsub *usbduxsub)
 {
         int errcode = 0;
+        uint8_t *local_transfer_buffer;
 
-        uint8_t local_transfer_buffer[16];
+        local_transfer_buffer = kmalloc(16, GFP_KERNEL);
+        if (!local_transfer_buffer)
+                return -ENOMEM;
 
         /* 7f92 to one */
         local_transfer_buffer[0] = 1;
@@ -732,12 +739,12 @@ static int usbduxsub_stop(struct usbduxsub *usbduxsub)
                                   1,
                                   /* Timeout */
                                   BULK_TIMEOUT);
-        if (errcode < 0) {
+        if (errcode < 0)
                 dev_err(&usbduxsub->interface->dev,
                         "comedi_: control msg failed (stop)\n");
-                return errcode;
-        }
-        return 0;
+
+        kfree(local_transfer_buffer);
+        return errcode;
 }
 
 static int usbduxsub_upload(struct usbduxsub *usbduxsub,