[PATCH net 1/4] net: hsr: fix packet drops caused by GRO superpackets
From: Xin Xie <hidden>
Date: 2026-07-22 17:18:41
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 append a 6-byte tag/RCT to every forwarded frame and process
each frame individually (sequence numbering, duplicate discard). When
a lower device aggregates received frames into a GRO super-packet --
in software, or in hardware on GRO_HW-capable NICs -- the HSR
receive/forward path mishandles it: frames are dropped and, on
memory-constrained devices, processing super-skbs in softirq context
can also pressure atomic memory allocation.
The HSR/PRP stack already disables LRO on enslaved devices for the
same reason. Extend that treatment to GRO: add netif_disable_gro()
and dev_disable_gro() mirroring netif_disable_lro()/dev_disable_lro(),
and call dev_disable_gro() from hsr_portdev_setup() so enslavement to
an HSR/PRP master automatically strips NETIF_F_GRO and NETIF_F_GRO_HW
on the lower device (recursively on its own lowers, as with LRO).
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 | 18 ++++++++++++++++++
net/core/dev_api.c | 16 ++++++++++++++++
net/hsr/hsr_slave.c | 1 +
4 files changed, 37 insertions(+)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 9981d637f..eba2c26a4 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 5933c5dab..a6cf2adc8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -1840,6 +1840,24 @@ 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); + + if (unlikely(dev->features & (NETIF_F_GRO | NETIF_F_GRO_HW))) + netdev_WARN(dev, "failed to disable GRO!\n"); + + 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 437947dd0..02fb21629 100644
--- a/net/core/dev_api.c
+++ b/net/core/dev_api.c@@ -269,6 +269,22 @@ 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 + * + * Disable 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. + */ +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 d9af9e65f..cefbbfbd5 100644
--- a/net/hsr/hsr_slave.c
+++ b/net/hsr/hsr_slave.c@@ -170,6 +170,7 @@ static int hsr_portdev_setup(struct hsr_priv *hsr, struct net_device *dev, if (res) goto fail_rx_handler; dev_disable_lro(dev); + dev_disable_gro(dev); return 0;
--
2.43.0