media: dib7000p: Fix potential division by zero

[ Upstream commit a1db7b2c5533fc67e2681eb5efc921a67bc7d5b8 ]

Variable loopdiv can be assigned 0, then it is used as a denominator,
without checking it for 0.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 713d54a8bd81 ("[media] DiB7090: add support for the dib7090 based")
Signed-off-by: Daniil Dulov <d.dulov@aladdin.ru>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil: (bw != NULL) -> bw]
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/media/dvb-frontends/dib7000p.c b/drivers/media/dvb-frontends/dib7000p.c
index a90d2f51868ff0b9d9e2add77bca6a9f8f087895..632534eff0ffa2f84719e218f0159040d0331ffb 100644 (file)
--- a/drivers/media/dvb-frontends/dib7000p.c
+++ b/drivers/media/dvb-frontends/dib7000p.c
@@ -497,7 +497,7 @@ static int dib7000p_update_pll(struct dvb_frontend *fe, struct dibx000_bandwidth
        prediv = reg_1856 & 0x3f;
        loopdiv = (reg_1856 >> 6) & 0x3f;
 
-       if ((bw != NULL) && (bw->pll_prediv != prediv || bw->pll_ratio != loopdiv)) {
+       if (loopdiv && bw && (bw->pll_prediv != prediv || bw->pll_ratio != loopdiv)) {
                dprintk("Updating pll (prediv: old =  %d new = %d ; loopdiv : old = %d new = %d)\n", prediv, bw->pll_prediv, loopdiv, bw->pll_ratio);
                reg_1856 &= 0xf000;
                reg_1857 = dib7000p_read_word(state, 1857);