From: Colin Ian King colin.king@canonical.com
[ Upstream commit a7463e2dc698075132de9905b89f495df888bb79 ]
The shifting of buf[3] by 24 bits to the left will be promoted to a 32 bit signed int and then sign-extended to an unsigned long. In the unlikely event that the the top bit of buf[3] is set then all then all the upper bits end up as also being set because of the sign-extension and this affect the ev->post_bit_error sum. Fix this by using the temporary u32 variable bit_error to avoid the sign-extension promotion. This also removes the need to do the computation twice.
Addresses-Coverity: ("Unintended sign extension")
Fixes: 267897a4708f ("[media] tda10071: implement DVBv5 statistics") Signed-off-by: Colin Ian King colin.king@canonical.com Signed-off-by: Sean Young sean@mess.org Signed-off-by: Mauro Carvalho Chehab mchehab+huawei@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/media/dvb-frontends/tda10071.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/media/dvb-frontends/tda10071.c b/drivers/media/dvb-frontends/tda10071.c index 097c42d3f8c2..df0c7243eafe 100644 --- a/drivers/media/dvb-frontends/tda10071.c +++ b/drivers/media/dvb-frontends/tda10071.c @@ -483,10 +483,11 @@ static int tda10071_read_status(struct dvb_frontend *fe, enum fe_status *status) goto error;
if (dev->delivery_system == SYS_DVBS) { - dev->dvbv3_ber = buf[0] << 24 | buf[1] << 16 | - buf[2] << 8 | buf[3] << 0; - dev->post_bit_error += buf[0] << 24 | buf[1] << 16 | - buf[2] << 8 | buf[3] << 0; + u32 bit_error = buf[0] << 24 | buf[1] << 16 | + buf[2] << 8 | buf[3] << 0; + + dev->dvbv3_ber = bit_error; + dev->post_bit_error += bit_error; c->post_bit_error.stat[0].scale = FE_SCALE_COUNTER; c->post_bit_error.stat[0].uvalue = dev->post_bit_error; dev->block_error += buf[4] << 8 | buf[5] << 0;