From accb298fb2e3d09a84bd92595b115232f14a5e60 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Mon, 20 Apr 2015 11:49:05 -0700 Subject: [PATCH] staging: comedi: ni_nio_common: don't write non-existing caldac's ni_write_caldac() checks the boardinfo 'caldac' array to determine what caldac is used for a given 'addr'. It then calculates the 'bitstring' and number of 'bits' used to write a value to that caldac address. After checking the caldac array, if the number of bits is 0 there is no caldac associated with the address. If this happens we shouldn't try writing to the non-existing caldac. Reported-by: coverity (CID 1192116) Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/ni_mio_common.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c index c66affd993aa..69d71f328006 100644 --- a/drivers/staging/comedi/drivers/ni_mio_common.c +++ b/drivers/staging/comedi/drivers/ni_mio_common.c @@ -4355,6 +4355,10 @@ static void ni_write_caldac(struct comedi_device *dev, int addr, int val) addr -= caldacs[type].n_chans; } + /* bits will be 0 if there is no caldac for the given addr */ + if (bits == 0) + return; + for (bit = 1 << (bits - 1); bit; bit >>= 1) { ni_writeb(dev, ((bit & bitstring) ? 0x02 : 0), Serial_Command); udelay(1); -- 2.34.1