[PATCH net-next] net: vxlan: check ipv6_mod_enabled() on neigh_reduce()

[PATCH net-next] net: vxlan: check ipv6_mod_enabled() on neigh_reduce()

[Fernando Fernandez Mancera]

IPv6 must be enabled or otherwise neigh_reduce() might cause a kernel
panic. This was prevented by a check on in6_dev. Use ipv6_mod_enabled()
instead as it is cleaner and also consistent with the code at
route_shortcircuit().

Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
---
 drivers/net/vxlan/vxlan_core.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index b5fbd03418b6..b3b692c4b628 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2027,13 +2027,11 @@ static int neigh_reduce(struct net_device *dev, struct sk_buff *skb, __be32 vni)
 	struct vxlan_dev *vxlan = netdev_priv(dev);
 	const struct in6_addr *daddr;
 	const struct ipv6hdr *iphdr;
-	struct inet6_dev *in6_dev;
 	struct neighbour *n;
 	struct nd_msg *msg;
 
 	rcu_read_lock();
-	in6_dev = __in6_dev_get(dev);
-	if (!in6_dev)
+	if (unlikely(!ipv6_mod_enabled()))
 		goto out;
 
 	iphdr = ipv6_hdr(skb);
-- 
2.53.0

Re: [PATCH net-next] net: vxlan: check ipv6_mod_enabled() on neigh_reduce()

[Ido Schimmel]

On Mon, Mar 30, 2026 at 02:10:33PM +0200, Fernando Fernandez Mancera wrote:
> IPv6 must be enabled or otherwise neigh_reduce() might cause a kernel
> panic. This was prevented by a check on in6_dev. Use ipv6_mod_enabled()
> instead as it is cleaner and also consistent with the code at
> route_shortcircuit().
> 
> Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>

I believe the RCU read-side critical section could be reduced a bit, but
it's not critical, so:

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

Re: [PATCH net-next] net: vxlan: check ipv6_mod_enabled() on neigh_reduce()

[patchwork-bot+netdevbpf]

Hello:

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

On Mon, 30 Mar 2026 14:10:33 +0200 you wrote:
> IPv6 must be enabled or otherwise neigh_reduce() might cause a kernel
> panic. This was prevented by a check on in6_dev. Use ipv6_mod_enabled()
> instead as it is cleaner and also consistent with the code at
> route_shortcircuit().
> 
> Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
> 
> [...]

Here is the summary with links:
  - [net-next] net: vxlan: check ipv6_mod_enabled() on neigh_reduce()
    https://git.kernel.org/netdev/net-next/c/58e416e28328

You are awesome, thank you!
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