Re: [PATCH v2 net-next 7/7] ip_tunnel: Support per-netns device unregistration.
From: Ido Schimmel <idosch@nvidia.com>
Date: 2026-09-10 17:13:22
On Wed, Sep 09, 2026 at 11:43:50PM +0000, Kuniyuki Iwashima wrote:
quoted hunk ↗ jump to hunk
@@ -920,6 +927,11 @@ int ip_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm_kern *p, mutex_lock(&itn->tunnels_lock); + if (!itn->fb_tunnel_dev) { + err = -EBUSY; + goto done; + }
This is a problem in network namespaces where fallback tunnels are not created and the pointer is set to NULL. Before: # sysctl -wq net.core.fb_tunnels_only_for_init_net=1 # ip netns add bla # ip -n bla link add name gre1 up type gre local 192.0.2.1 remote 198.51.100.1 # ip -n bla tunnel show gre1 gre1: gre/ip remote 198.51.100.1 local 192.0.2.1 ttl inherit After: # sysctl -wq net.core.fb_tunnels_only_for_init_net=1 # ip netns add bla # ip -n bla link add name gre1 up type gre local 192.0.2.1 remote 198.51.100.1 # ip -n bla tunnel show gre1 get tunnel "gre1" failed: Device or resource busy