[PATCH net-next v2] ipv4: nexthop: handle errors in nexthop_init()

[PATCH net-next v2] ipv4: nexthop: handle errors in nexthop_init()

[Minhong He]

nexthop_init() ignores errors from register_pernet_subsys() and
register_netdevice_notifier(), so a partial initialization can appear
successful.

Check those steps and unwind prior registrations on failure.

Do not check rtnl_register_many(): for built-in code it panics on
failure, so the call cannot return an error to nexthop_init().

Signed-off-by: Minhong He <heminhong@kylinos.cn>
---
v2:
- Drop rtnl_register_many() error handling; built-in registration panics
  on failure
- Retarget to net-next
v1: https://lore.kernel.org/all/20260728031055.76708-1-heminhong@kylinos.cn/

 net/ipv4/nexthop.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index 6205bd57aa85..aa2fa17391e7 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -4192,12 +4192,22 @@ static const struct rtnl_msg_handler nexthop_rtnl_msg_handlers[] __initconst = {
 
 static int __init nexthop_init(void)
 {
-	register_pernet_subsys(&nexthop_net_ops);
+	int err;
 
-	register_netdevice_notifier(&nh_netdev_notifier);
+	err = register_pernet_subsys(&nexthop_net_ops);
+	if (err)
+		return err;
+
+	err = register_netdevice_notifier(&nh_netdev_notifier);
+	if (err)
+		goto err_unregister_pernet;
 
 	rtnl_register_many(nexthop_rtnl_msg_handlers);
 
 	return 0;
+
+err_unregister_pernet:
+	unregister_pernet_subsys(&nexthop_net_ops);
+	return err;
 }
 subsys_initcall(nexthop_init);
-- 
2.25.1

Re: [PATCH net-next v2] ipv4: nexthop: handle errors in nexthop_init()

[Ido Schimmel]

On Fri, Jul 31, 2026 at 10:52:49AM +0800, Minhong He wrote:
> nexthop_init() ignores errors from register_pernet_subsys() and
> register_netdevice_notifier(), so a partial initialization can appear
> successful.
> 
> Check those steps and unwind prior registrations on failure.
> 
> Do not check rtnl_register_many(): for built-in code it panics on
> failure, so the call cannot return an error to nexthop_init().
> 
> Signed-off-by: Minhong He <heminhong@kylinos.cn>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>

Re: [PATCH net-next v2] ipv4: nexthop: handle errors in nexthop_init()

[patchwork-bot+netdevbpf]

Hello:

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

On Fri, 31 Jul 2026 10:52:49 +0800 you wrote:
> nexthop_init() ignores errors from register_pernet_subsys() and
> register_netdevice_notifier(), so a partial initialization can appear
> successful.
> 
> Check those steps and unwind prior registrations on failure.
> 
> Do not check rtnl_register_many(): for built-in code it panics on
> failure, so the call cannot return an error to nexthop_init().
> 
> [...]

Here is the summary with links:
  - [net-next,v2] ipv4: nexthop: handle errors in nexthop_init()
    https://git.kernel.org/netdev/net-next/c/c0fd47726c94

You are awesome, thank you!
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