[PATCH net v2] net: spacemit: Check IFF_UP in emac_set_pauseparam()

[Vivian Wang]

Currently, emac_set_pauseparam() will oops if userspace calls it while
the interface is not up, because phydev is NULL, but it is still
accessed in emac_set_fc() and emac_set_fc_autoneg().

Check for IFF_UP in emac_set_pauseparam() before proceeding.

Fixes: bfec6d7f2001 ("net: spacemit: Add K1 Ethernet MAC")
Signed-off-by: Vivian Wang <wangruikang at iscas.ac.cn>
---
Changes in v2:
- Reduced patch to only contain checking IFF_UP to avoid the oops. More
  invasive changes will be sent to net-next in the future. (Andrew)
- Link to v1: https://lore.kernel.org/r/20251031-k1-ethernet-remove-fc-v1-1-1ae3f1d6508c@iscas.ac.cn
---
 drivers/net/ethernet/spacemit/k1_emac.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/spacemit/k1_emac.c b/drivers/net/ethernet/spacemit/k1_emac.c
index e1c5faff3b71..a3fc17d2ca10 100644
--- a/drivers/net/ethernet/spacemit/k1_emac.c
+++ b/drivers/net/ethernet/spacemit/k1_emac.c
@@ -1441,6 +1441,9 @@ static int emac_set_pauseparam(struct net_device *dev,
 	struct emac_priv *priv = netdev_priv(dev);
 	u8 fc = 0;
 
+	if (!(dev->flags & IFF_UP))
+		return -ENETDOWN;
+
 	priv->flow_control_autoneg = pause->autoneg;
 
 	if (pause->autoneg) {

---
base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787
change-id: 20251031-k1-ethernet-remove-fc-82fd67d889a6

Best regards,
-- 
Vivian "dramforever" Wang