[PATCH 1/4] net: hsr: fix packet drops caused by GRO superpackets
From: Xin Xie <hidden>
Date: 2026-08-09 12:15:00
Also in:
linux-kselftest, lkml, stable
Subsystem:
hsr network protocol, networking drivers, networking [general], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
HSR/PRP process each wire frame separately for tagging and duplicate
discard. GRO on a lower device hides multiple frames in one skb, which
cannot be forwarded with valid per-frame metadata.
Disable GRO and GRO_HW when a lower device is enslaved, matching the
existing LRO handling.
This is best effort because GRO may be re-enabled and some devices cannot
disable GRO_HW. The forward-entry segmentation fix handles plain,
trailer-free GSO skbs that still arrive; device-specific fixed-on GRO_HW
output is outside this guarantee.
Fixes: f421436a591d ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Cc: stable@vger.kernel.org
Signed-off-by: Xin Xie <redacted>
---
include/linux/netdevice.h | 2 ++
net/core/dev.c | 15 +++++++++++++++
net/core/dev_api.c | 21 +++++++++++++++++++++
net/hsr/hsr_slave.c | 5 +++++
4 files changed, 43 insertions(+)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 9981d637f8b5..eba2c26a49ba 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h@@ -3434,6 +3434,8 @@ void dev_close(struct net_device *dev); void netif_close_many(struct list_head *head, bool unlink); void netif_disable_lro(struct net_device *dev); void dev_disable_lro(struct net_device *dev); +void netif_disable_gro(struct net_device *dev); +void dev_disable_gro(struct net_device *dev); int dev_loopback_xmit(struct net *net, struct sock *sk, struct sk_buff *newskb); u16 dev_pick_tx_zero(struct net_device *dev, struct sk_buff *skb, struct net_device *sb_dev);
diff --git a/net/core/dev.c b/net/core/dev.c
index 5933c5dab09e..f20d5ab0cf72 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -1840,6 +1840,21 @@ void netif_disable_lro(struct net_device *dev) } } +void netif_disable_gro(struct net_device *dev) +{ + struct net_device *lower_dev; + struct list_head *iter; + + dev->wanted_features &= ~(NETIF_F_GRO | NETIF_F_GRO_HW); + netdev_update_features(dev); + + netdev_for_each_lower_dev(dev, lower_dev, iter) { + netdev_lock_ops(lower_dev); + netif_disable_gro(lower_dev); + netdev_unlock_ops(lower_dev); + } +} + /** * dev_disable_gro_hw - disable HW Generic Receive Offload on a device * @dev: device
diff --git a/net/core/dev_api.c b/net/core/dev_api.c
index 437947dd08ed..3ca2515ad048 100644
--- a/net/core/dev_api.c
+++ b/net/core/dev_api.c@@ -269,6 +269,27 @@ void dev_disable_lro(struct net_device *dev) } EXPORT_SYMBOL(dev_disable_lro); +/** + * dev_disable_gro() - disable Generic Receive Offload on a device + * @dev: device + * + * Best-effort disable of Generic Receive Offload (GRO) on a net + * device. Must be called under RTNL. This is needed if received + * packets may be forwarded to another interface. + * + * The disable is best-effort: a device with a fixed-on feature (for + * example GRO_HW on a virtio-net device negotiated without + * VIRTIO_NET_F_CTRL_GUEST_OFFLOADS) keeps it enabled. Callers that + * need a hard guarantee must inspect the resulting feature state. + */ +void dev_disable_gro(struct net_device *dev) +{ + netdev_lock_ops(dev); + netif_disable_gro(dev); + netdev_unlock_ops(dev); +} +EXPORT_SYMBOL(dev_disable_gro); + /** * dev_set_promiscuity() - update promiscuity count on a device * @dev: device
diff --git a/net/hsr/hsr_slave.c b/net/hsr/hsr_slave.c
index 01c73b4b50dd..bb2182a169a3 100644
--- a/net/hsr/hsr_slave.c
+++ b/net/hsr/hsr_slave.c@@ -171,6 +171,11 @@ static int hsr_portdev_setup(struct hsr_priv *hsr, struct net_device *dev, goto fail_rx_handler; dev_disable_lro(dev); + /* GRO disabling is best-effort: fixed-on GRO_HW cannot be + * forced off, and GRO may be re-enabled later via ethtool. + */ + dev_disable_gro(dev); + return 0; fail_rx_handler:
--
2.43.0