From: Arnd Bergmann
Date: Tue, 13 Mar 2018 12:44:53 +0100
> The new variable is only available when CONFIG_SYSCTL is enabled,
> otherwise we get a link error:
>
> net/ipv4/ip_tunnel.o: In function `ip_tunnel_init_net':
> ip_tunnel.c:(.text+0x278b): undefined reference to
>
The new variable is only available when CONFIG_SYSCTL is enabled,
otherwise we get a link error:
net/ipv4/ip_tunnel.o: In function `ip_tunnel_init_net':
ip_tunnel.c:(.text+0x278b): undefined reference to
`sysctl_fb_tunnels_only_for_init_net'
net/ipv6/sit.o: In function `sit_init_net':