From: Ian Abbott <abbotti@mev.co.uk>
Date: Thu, 15 Dec 2011 20:57:29 +0000 (+0000)
Subject: das1800: don't access *data when insn->bits == 0
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=d081b7b8f845e39b2653c5faf8502dc1232124aa;p=comedi.git

das1800: don't access *data when insn->bits == 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/das1800.c b/comedi/drivers/das1800.c
index d35b67e5..1e0defe4 100644
--- a/comedi/drivers/das1800.c
+++ b/comedi/drivers/das1800.c
@@ -1621,6 +1621,9 @@ static int das1800_ao_winsn(comedi_device * dev, comedi_subdevice * s,
 	short output;
 	unsigned long irq_flags;
 
+	if (insn->n == 0)
+		return 0;
+
 	//  card expects two's complement data
 	output = data[0] - (1 << (thisboard->resolution - 1));
 	// if the write is to the 'update' channel, we need to remember its value