# \[PATCH 4.9 097/207\] b43: fix a lower bounds test

- From: Greg Kroah-Hartman \<gregkh@linuxfoundation.org\>
- Date: 2021-11-24 12:23:54 
- List: stable
- Page: https://ratatoskr.run/stable/2021/11/1584075
- Thread: https://ratatoskr.run/stable/2021/11/1583929/t/2.md

```text
From: Dan Carpenter <redacted>

[ Upstream commit 9b793db5fca44d01f72d3564a168171acf7c4076 ]

The problem is that "channel" is an unsigned int, when it's less 5 the
value of "channel - 5" is not a negative number as one would expect but
is very high positive value instead.

This means that "start" becomes a very high positive value.  The result
of that is that we never enter the "for (i = start; i <= end; i++) {"
loop.  Instead of storing the result from b43legacy_radio_aci_detect()
it just uses zero.

Fixes: ef1a628d83fc ("b43: Implement dynamic PHY API")
Signed-off-by: Dan Carpenter <redacted>
Acked-by: Michael Büsch <m@bues.ch>
Signed-off-by: Kalle Valo <redacted>
Link: https://lore.kernel.org/r/20211006073621.GE8404@kili
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/broadcom/b43/phy_g.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/broadcom/b43/phy_g.c b/drivers/net/wireless/broadcom/b43/phy_g.c
index 822dcaa8ace63..35ff139b1496e 100644
--- a/drivers/net/wireless/broadcom/b43/phy_g.c
+++ b/drivers/net/wireless/broadcom/b43/phy_g.c
@@ -2310,7 +2310,7 @@ static u8 b43_gphy_aci_scan(struct b43_wldev *dev)
 	b43_phy_mask(dev, B43_PHY_G_CRS, 0x7FFF);
 	b43_set_all_gains(dev, 3, 8, 1);
 
-	start = (channel - 5 > 0) ? channel - 5 : 1;
+	start = (channel > 5) ? channel - 5 : 1;
 	end = (channel + 5 < 14) ? channel + 5 : 13;
 
 	for (i = start; i <= end; i++) {
-- 
2.33.0



```