From: H Hartley Sweeten <hsweeten@visionengravers.com>
Date: Mon, 10 Aug 2015 20:14:01 +0000 (-0700)
Subject: staging: comedi: comedi_fops: remove BUG_ON() in comedi_free_subdevice_minor()
X-Git-Tag: firefly_0821_release~176^2~1221^2~104
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5104a8988723b405c9e033b7e57267ebdd387d4d;p=firefly-linux-kernel-4.4.55.git

staging: comedi: comedi_fops: remove BUG_ON() in comedi_free_subdevice_minor()

Drivers should not crash the kernel.

This function is only called by comedi_device_detach_cleanup() and the
s->minor will always be valid or the device wouldn't have attached in
the first place.

Leave the checks for safety in accessing the comedi_subdevice_minor_table
array but remove the BUG_ON() calls.

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/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 93b37e245f96..2e69f5a4e7ec 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2836,12 +2836,10 @@ void comedi_free_subdevice_minor(struct comedi_subdevice *s)
 
 	if (!s)
 		return;
-	if (s->minor < 0)
+	if (s->minor < COMEDI_NUM_BOARD_MINORS ||
+	    s->minor >= COMEDI_NUM_MINORS)
 		return;
 
-	BUG_ON(s->minor >= COMEDI_NUM_MINORS);
-	BUG_ON(s->minor < COMEDI_NUM_BOARD_MINORS);
-
 	i = s->minor - COMEDI_NUM_BOARD_MINORS;
 	mutex_lock(&comedi_subdevice_minor_table_lock);
 	if (s == comedi_subdevice_minor_table[i])