[PATCH 6.12 054/567] broadcom: b44: prevent uninitialized value usage

Greg Kroah-Hartman
2026-01-06T17:17:14Z

From: Alexey Simakov <bigalex934@gmail.com>

[ Upstream commit 50b3db3e11864cb4e18ff099cfb38e11e7f87a68 ]

On execution path with raised B44_FLAG_EXTERNAL_PHY, b44_readphy()
leaves bmcr value uninitialized and it is used later in the code.

Add check of this flag at the beginning of the b44_nway_reset() and
exit early of the function with restarting autonegotiation if an
external PHY is used.

Fixes: 753f492093da ("[B44]: port to native ssb support")
Reviewed-by: Jonas Gorski <jonas.gorski@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Alexey Simakov <bigalex934@gmail.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20251205155815.4348-1-bigalex934@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/broadcom/b44.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/broadcom/b44.c b/drivers/net/ethernet/broadcom/b44.c
index e5809ad5eb827..29f0de9e31545 100644
--- a/drivers/net/ethernet/broadcom/b44.c
+++ b/drivers/net/ethernet/broadcom/b44.c
@@ -1789,6 +1789,9 @@ static int b44_nway_reset(struct net_device *dev)
u32 bmcr;
int r;

+ if (bp->flags & B44_FLAG_EXTERNAL_PHY)
+ return phy_ethtool_nway_reset(dev);
+
spin_lock_irq(&bp->lock);
b44_readphy(bp, MII_BMCR, &bmcr);
b44_readphy(bp, MII_BMCR, &bmcr);
--
2.51.0