From: H Hartley Sweeten <hartleys@visionengravers.com>
Date: Sat, 18 Aug 2012 01:21:12 +0000 (-0700)
Subject: staging: comedi: adv_pci_dio: fix bug in 'detach'
X-Git-Tag: firefly_0821_release~3680^2~1977^2~834
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f853d9ddf4867a4629753be4af7c5b98f7b7edd0;p=firefly-linux-kernel-4.4.55.git

staging: comedi: adv_pci_dio: fix bug in 'detach'

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@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/comedi/drivers/adv_pci_dio.c b/drivers/staging/comedi/drivers/adv_pci_dio.c
index 4da0e7bd204f..a4c1b13136bc 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)