queue-6.1/bonding-only-set-speed-duplex-to-unknown-if-getting-.patch

From bf3a728d72d717f29c97d9d776055c4b598a0d7d Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Tue, 3 Feb 2026 15:11:52 +0100
Subject: bonding: only set speed/duplex to unknown, if getting speed failed

From: Thomas Bogendoerfer <tbogendoerfer@suse.de>

[ Upstream commit 48dec8d88af96039a4a17b8c2f148f2a4066e195 ]

bond_update_speed_duplex() first set speed/duplex to unknown and
then asks slave driver for current speed/duplex. Since getting
speed/duplex might take longer there is a race, where this false state
is visible by /proc/net/bonding. With commit 691b2bf14946 ("bonding:
 update port speed when getting bond speed") this race gets more visible,
if user space is calling ethtool on a regular base.

Fix this by only setting speed/duplex to unknown, if link speed is
really unknown/unusable.

Fixes: 98f41f694f46 ("bonding:update speed/duplex for NETDEV_CHANGE")
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Acked-by: Jay Vosburgh <jv@jvosburgh.net>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Link: https://patch.msgid.link/20260203141153.51581-1-tbogendoerfer@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/bonding/bond_main.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 71912ddfa7149..113a5504c9ebb 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -712,26 +712,29 @@ static int bond_update_speed_duplex(struct slave *slave)
 	struct ethtool_link_ksettings ecmd;
 	int res;
 
-	slave->speed = SPEED_UNKNOWN;
-	slave->duplex = DUPLEX_UNKNOWN;
-
 	res = __ethtool_get_link_ksettings(slave_dev, &ecmd);
 	if (res < 0)
-		return 1;
+		goto speed_duplex_unknown;
 	if (ecmd.base.speed == 0 || ecmd.base.speed == ((__u32)-1))
-		return 1;
+		goto speed_duplex_unknown;
 	switch (ecmd.base.duplex) {
 	case DUPLEX_FULL:
 	case DUPLEX_HALF:
 		break;
 	default:
-		return 1;
+		goto speed_duplex_unknown;
 	}
 
 	slave->speed = ecmd.base.speed;
 	slave->duplex = ecmd.base.duplex;
 
 	return 0;
+
+speed_duplex_unknown:
+	slave->speed = SPEED_UNKNOWN;
+	slave->duplex = DUPLEX_UNKNOWN;
+
+	return 1;
 }
 
 const char *bond_slave_link_status(s8 link)
-- 
2.51.0