From: Ido Schimmel <idosch@nvidia.com>
To: Kuniyuki Iwashima <kuniyu@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
David Ahern <dsahern@kernel.org>, Simon Horman <horms@kernel.org>,
Steffen Klassert <steffen.klassert@secunet.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
Kuniyuki Iwashima <kuni1840@gmail.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH v2 net-next 7/7] ip_tunnel: Support per-netns device unregistration.
Date: Thu, 10 Sep 2026 20:13:01 +0300 [thread overview]
Message-ID: <20260910171301.GA1902749@shredder> (raw)
In-Reply-To: <20260909234422.2416506-8-kuniyu@google.com>
On Wed, Sep 09, 2026 at 11:43:50PM +0000, Kuniyuki Iwashima wrote:
> @@ -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
next prev parent reply other threads:[~2026-09-10 17:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-09 23:43 [PATCH v2 net-next 0/7] ip_tunnel: Support per-netns device unregistration Kuniyuki Iwashima
2026-09-09 23:43 ` [PATCH v2 net-next 1/7] ipmr: Call ->dellink() to remove DVMRP tunnel device Kuniyuki Iwashima
2026-09-09 23:43 ` [PATCH v2 net-next 2/7] ip_tunnel: Set itn->fb_tunnel_dev to NULL in ip_tunnel_delete_net() Kuniyuki Iwashima
2026-09-11 2:44 ` netdev-bot+sashiko
2026-09-09 23:43 ` [PATCH v2 net-next 3/7] ip_tunnel: Don't pass rtnl_link_ops to ip_tunnel_delete_net() Kuniyuki Iwashima
2026-09-09 23:43 ` [PATCH v2 net-next 4/7] ip_tunnel: Centralise ip_tunnel_del() to ip_tunnel_dellink() Kuniyuki Iwashima
2026-09-09 23:43 ` [PATCH v2 net-next 5/7] ip_tunnel: Unify error paths in ip_tunnel_newlink() and ip_tunnel_changelink() Kuniyuki Iwashima
2026-09-09 23:43 ` [PATCH v2 net-next 6/7] ip_tunnel: Protect ip_tunnel_net.tunnels[] with mutex Kuniyuki Iwashima
2026-09-11 2:44 ` netdev-bot+sashiko
2026-09-09 23:43 ` [PATCH v2 net-next 7/7] ip_tunnel: Support per-netns device unregistration Kuniyuki Iwashima
2026-09-10 17:13 ` Ido Schimmel [this message]
2026-09-10 17:35 ` Kuniyuki Iwashima
2026-09-11 2:44 ` netdev-bot+sashiko
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