From: Alexey Simakov <bigalex934@gmail.com>
Date: Fri, 5 Dec 2025 15:58:16 +0000 (+0300)
Subject: broadcom: b44: prevent uninitialized value usage
X-Git-Tag: v5.15.198~320
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a94493dd78b4ebd7f9c3433c6129fb889fcb5b29;p=thirdparty%2Fkernel%2Fstable.git

broadcom: b44: prevent uninitialized value usage

[ 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>
---

diff --git a/drivers/net/ethernet/broadcom/b44.c b/drivers/net/ethernet/broadcom/b44.c
index ce370ef641f01..3c4e0a78b8a03 100644
--- a/drivers/net/ethernet/broadcom/b44.c
+++ b/drivers/net/ethernet/broadcom/b44.c
@@ -1811,6 +1811,9 @@ 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);