[v1] ipv6: route: Unregister netdevice notifier on BPF init failure

[PATCH v1] ipv6: route: Unregister netdevice notifier on BPF init failure

Posted by Yuho Choi 4 weeks, 1 day ago

ip6_route_init() registers ip6_route_dev_notifier before registering the
IPv6 route BPF iterator target. If bpf_iter_register() fails, the error
path jumps to out_register_late_subsys and unwinds the RTNL handlers and
late pernet subsystem, but leaves the netdevice notifier registered.

Add a separate unwind label for the BPF iterator failure path so the
netdevice notifier is unregistered before continuing with the existing
cleanup.

Fixes: 138d0be35b14 ("net: bpf: Add netlink and ipv6_route bpf_iter targets")
Signed-off-by: Yuho Choi <dbgh9129@gmail.com>
---
 net/ipv6/route.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index cb521700cee7..4333e11dc9c5 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -6925,7 +6925,7 @@ int __init ip6_route_init(void)
 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
 	ret = bpf_iter_register();
 	if (ret)
-		goto out_register_late_subsys;
+		goto out_register_notifier;
 #endif
 #endif
 
@@ -6939,6 +6939,12 @@ int __init ip6_route_init(void)
 out:
 	return ret;
 
+#if IS_BUILTIN(CONFIG_IPV6)
+#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
+out_register_notifier:
+	unregister_netdevice_notifier(&ip6_route_dev_notifier);
+#endif
+#endif
 out_register_late_subsys:
 	rtnl_unregister_all(PF_INET6);
 	unregister_pernet_subsys(&ip6_route_net_late_ops);
-- 
2.43.0

Re: [PATCH v1] ipv6: route: Unregister netdevice notifier on BPF init failure

Posted by Jakub Kicinski 4 weeks ago

On Wed, 13 May 2026 20:22:18 -0400 Yuho Choi wrote:
> ip6_route_init() registers ip6_route_dev_notifier before registering the
> IPv6 route BPF iterator target. If bpf_iter_register() fails, the error
> path jumps to out_register_late_subsys and unwinds the RTNL handlers and
> late pernet subsystem, but leaves the netdevice notifier registered.
> 
> Add a separate unwind label for the BPF iterator failure path so the
> netdevice notifier is unregistered before continuing with the existing
> cleanup.
> 
> Fixes: 138d0be35b14 ("net: bpf: Add netlink and ipv6_route bpf_iter targets")
> Signed-off-by: Yuho Choi <dbgh9129@gmail.com>

> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index cb521700cee7..4333e11dc9c5 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -6925,7 +6925,7 @@ int __init ip6_route_init(void)
>  #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
>  	ret = bpf_iter_register();
>  	if (ret)
> -		goto out_register_late_subsys;
> +		goto out_register_notifier;
>  #endif
>  #endif
>  
> @@ -6939,6 +6939,12 @@ int __init ip6_route_init(void)
>  out:
>  	return ret;
>  
> +#if IS_BUILTIN(CONFIG_IPV6)

Why this check?

> +#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
> +out_register_notifier:
> +	unregister_netdevice_notifier(&ip6_route_dev_notifier);
> +#endif
> +#endif
-- 
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