staging: comedi: das16: fix das16_detach()

The function das16_reset() needs a valid dev->iobase. Since the iobase
is requested after the devpriv has been allocated in the attach, move
the das16_reset() call into the if (devpriv) and add a if (dev->iobase).

Also, move the release of the extra iobase into the if (devpriv) to
prevent an invalid memory access.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.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/das16.c b/drivers/staging/comedi/drivers/das16.c
index 60895e658c43ade4b7e8dc6cfc6d721db4aef3f4..9944f715b5daf39785bd64510e1d39caae153106 100644 (file)
--- a/drivers/staging/comedi/drivers/das16.c
+++ b/drivers/staging/comedi/drivers/das16.c
@@ -1206,10 +1206,12 @@ static void das16_detach(struct comedi_device *dev)
 {
        const struct das16_board *board = comedi_board(dev);
        struct das16_private_struct *devpriv = dev->private;
+       int i;
 
-       das16_reset(dev);
        if (devpriv) {
-               int i;
+               if (dev->iobase)
+                       das16_reset(dev);
+
                for (i = 0; i < 2; i++) {
                        if (devpriv->dma_buffer[i])
                                pci_free_consistent(NULL, DAS16_DMA_SIZE,
@@ -1221,9 +1223,12 @@ static void das16_detach(struct comedi_device *dev)
                        free_dma(devpriv->dma_chan);
                kfree(devpriv->user_ai_range_table);
                kfree(devpriv->user_ao_range_table);
+
+               if (devpriv->extra_iobase)
+                       release_region(devpriv->extra_iobase,
+                                      board->size & 0x3ff);
        }
-       if (devpriv->extra_iobase)
-               release_region(devpriv->extra_iobase, board->size & 0x3ff);
+
        comedi_legacy_detach(dev);
 }