From: Ian Abbott <abbotti@mev.co.uk>
Date: Thu, 15 Dec 2011 19:44:40 +0000 (+0000)
Subject: cb_pcidda: don't access *data when insn->n == 0
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=d5ca73b470e340933602c2e69880a99010e40e65;p=comedi.git

cb_pcidda: don't access *data when insn->n == 0

Due to recent change to do_insnlist_ioctl() and do_insn_ioctl(), the
'data' pointer will be NULL when insn->n == 0.  Do not access *data
in this case.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
---

diff --git a/comedi/drivers/cb_pcidda.c b/comedi/drivers/cb_pcidda.c
index 74b8fe03..5f08f0cd 100644
--- a/comedi/drivers/cb_pcidda.c
+++ b/comedi/drivers/cb_pcidda.c
@@ -604,6 +604,9 @@ static int cb_pcidda_ao_winsn(comedi_device * dev, comedi_subdevice * s,
 	unsigned int command;
 	unsigned int channel, range;
 
+	if (insn->n == 0)
+		return 0;
+
 	channel = CR_CHAN(insn->chanspec);
 	range = CR_RANGE(insn->chanspec);