[PATCH 20/20] staging: comedi: adv_pci_dio: fix bug in 'detach'

[H Hartley Sweeten]

The 'attach' function can fail between when the devpriv and
the comedi subdevices are allocated. If it does the 'detach'
will try to access unallocated memory when it goes thru the
subdevices.

Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
Cc: Ian Abbott <abbotti at mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 drivers/staging/comedi/drivers/adv_pci_dio.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/staging/comedi/drivers/adv_pci_dio.c b/drivers/staging/comedi/drivers/adv_pci_dio.c
index 4da0e7b..a4c1b13 100644
--- a/drivers/staging/comedi/drivers/adv_pci_dio.c
+++ b/drivers/staging/comedi/drivers/adv_pci_dio.c
@@ -1184,6 +1184,8 @@ static void pci_dio_detach(struct comedi_device *dev)
 	if (devpriv) {
 		if (devpriv->valid)
 			pci_dio_reset(dev);
+	}
+	if (dev->subdevices) {
 		for (i = 0; i < dev->n_subdevices; i++) {
 			s = dev->subdevices + i;
 			if (s->type == COMEDI_SUBD_DIO)
-- 
1.7.11