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From: Aleksei Sviridkin <f@lex.la>
To: "Th\u00e9o Lebrun" <theo.lebrun@bootlin.com>
Cc: Conor Dooley <conor.dooley@microchip.com>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Russell King <linux@armlinux.org.uk>,
	Vineeth Karumanchi <vineeth.karumanchi@amd.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH net 1/2] net: macb: zero the link settings taprio reads back
Date: Wed,  2 Sep 2026 08:05:27 +0000	[thread overview]
Message-ID: <20260902080528.2211468-2-f@lex.la> (raw)
In-Reply-To: <20260902080528.2211468-1-f@lex.la>

phylink_ethtool_ksettings_get() fills only what the current link mode
provides. With no PHY attached it writes port and supported; on a fixed
or in-band link it also writes speed and duplex, but only if
base.rate_matching already reads RATE_MATCH_NONE, a field it never
writes itself and so takes from the caller. The ethtool core zeroes the
structure on every path into the op, so its callers never notice; the
taprio path passes a stack variable and reads a speed nobody wrote.

Fixes: 89934dbf169e ("net: macb: Add TAPRIO traffic scheduling support")
Assisted-by: LLM
Signed-off-by: Aleksei Sviridkin <f@lex.la>
---
 drivers/net/ethernet/cadence/macb_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 76ee4f506033..a43855db1e45 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -4297,7 +4297,7 @@ static int macb_taprio_setup_replace(struct net_device *netdev,
 	struct macb_queue_enst_config *enst_queue;
 	struct tc_taprio_sched_entry *entry;
 	struct macb *bp = netdev_priv(netdev);
-	struct ethtool_link_ksettings kset;
+	struct ethtool_link_ksettings kset = {};
 	struct macb_queue *queue;
 	u32 queue_mask;
 	u8 queue_id;
-- 
2.53.0


  reply	other threads:[~2026-09-02  8:05 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-02  8:05 [PATCH net 0/2] net: macb: fix the link speed the taprio setup reads Aleksei Sviridkin
2026-09-02  8:05 ` Aleksei Sviridkin [this message]
2026-09-02  8:32   ` [PATCH net 1/2] net: macb: zero the link settings taprio reads back Théo Lebrun
2026-09-02  8:05 ` [PATCH net 2/2] net: macb: reject an unknown link speed in the taprio setup Aleksei Sviridkin
2026-09-02  8:57   ` Théo Lebrun
2026-09-02 16:37   ` Andrew Lunn
2026-09-03 12:36     ` Aleksei Sviridkin

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