[PATCH net-next v3] hsr: broadcast netlink notifications in the device's net namespace

[PATCH net-next v3] hsr: broadcast netlink notifications in the device's net namespace

[Maoyi Xie]

The HSR generic netlink family sets .netnsok = true. HSR devices can
live in network namespaces other than init_net.

Two async notifiers broadcast events with genlmsg_multicast(). They
are hsr_nl_ringerror() and hsr_nl_nodedown(). That helper delivers
only on the default genl socket in init_net. So the events always land
in init_net. The network namespace of the device does not matter.

This has two effects. A listener in the device's own namespace never
sees its own ring error and node down events. A privileged listener in
init_net receives events from HSR devices in other namespaces. The
payload carries the peer node MAC (HSR_A_NODE_ADDR) and the slave port
ifindex (HSR_A_IFINDEX).

Switch both callers to genlmsg_multicast_netns(). Other families with
.netnsok = true already do this. Examples are gtp, ovpn, team,
batman-adv, netdev-genl, ethtool and handshake.

hsr_nl_ringerror() already has the slave port. It uses
dev_net(port->dev). hsr_nl_nodedown() takes the namespace from the
master port via hsr_port_get_hsr().

Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Maoyi Xie <maoyixie.tju@gmail.com>
---
v3: Drop the master NULL check that v2 added in hsr_nl_nodedown(). As
    Fernando pointed out, master cannot be NULL on this path. hsr_dellink()
    calls timer_delete_sync() on the background jobs before removing the
    master, so the notifier never runs without one. The check only produced
    a false positive static analysis report. Use master directly, which
    matches the existing fail path that already dereferences master->dev.
v2: Drop the Fixes and stable tags and target net-next. As discussed,
    this is more of a behavior change than a fix, and the .netnsok
    commit has been in since 5.6 with no report. The multicast stays
    inside the rcu_read_lock, which avoids taking a netns ref on this
    path. Fernando's Reviewed-by carried over.

Inquiry (2026-05-18):
https://lore.kernel.org/netdev/CAHPEe=GO=2qqWZPwBB4rrXc3mkD0dznp2K78nCsKwF=c-QwxEw@mail.gmail.com/
v1 [PATCH net] (2026-05-27):
https://lore.kernel.org/netdev/20260527075924.2707856-1-maoyixie.tju@gmail.com/
v2 [PATCH net-next] (2026-06-01):
https://lore.kernel.org/netdev/20260601022014.1175348-1-maoyixie.tju@gmail.com/

 net/hsr/hsr_netlink.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c
index f0ca23da3ab9..8099f2069a74 100644
--- a/net/hsr/hsr_netlink.c
+++ b/net/hsr/hsr_netlink.c
@@ -252,7 +252,8 @@ void hsr_nl_ringerror(struct hsr_priv *hsr, unsigned char addr[ETH_ALEN],
 		goto nla_put_failure;
 
 	genlmsg_end(skb, msg_head);
-	genlmsg_multicast(&hsr_genl_family, skb, 0, 0, GFP_ATOMIC);
+	genlmsg_multicast_netns(&hsr_genl_family, dev_net(port->dev),
+				skb, 0, 0, GFP_ATOMIC);
 
 	return;
 
@@ -288,8 +289,12 @@ void hsr_nl_nodedown(struct hsr_priv *hsr, unsigned char addr[ETH_ALEN])
 	if (res < 0)
 		goto nla_put_failure;
 
+	rcu_read_lock();
+	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
 	genlmsg_end(skb, msg_head);
-	genlmsg_multicast(&hsr_genl_family, skb, 0, 0, GFP_ATOMIC);
+	genlmsg_multicast_netns(&hsr_genl_family, dev_net(master->dev),
+				skb, 0, 0, GFP_ATOMIC);
+	rcu_read_unlock();
 
 	return;
 

base-commit: 8415598365503ced2e3d019491b0a2756c85c494
-- 
2.34.1

Re: [PATCH net-next v3] hsr: broadcast netlink notifications in the device's net namespace

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Thu,  4 Jun 2026 13:49:49 +0800 you wrote:
> The HSR generic netlink family sets .netnsok = true. HSR devices can
> live in network namespaces other than init_net.
> 
> Two async notifiers broadcast events with genlmsg_multicast(). They
> are hsr_nl_ringerror() and hsr_nl_nodedown(). That helper delivers
> only on the default genl socket in init_net. So the events always land
> in init_net. The network namespace of the device does not matter.
> 
> [...]

Here is the summary with links:
  - [net-next,v3] hsr: broadcast netlink notifications in the device's net namespace
    https://git.kernel.org/netdev/net-next/c/a762fabd7ef9

You are awesome, thank you!
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