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>

diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
index d066351a71b2793d4f1ad60dd27e8db7dd0ea0e7..a728c8fc32a270e4a8963dc0eca3e14799fd6602 100644 (file)
--- 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,