The ipv6 gre implementation was cleaned up to share more code with the ipv4 version, but it can be enabled even when NET_IPGRE_DEMUX is disabled, resulting in a link error:
net/built-in.o: In function `gre_rcv': :(.text+0x17f5d0): undefined reference to `gre_parse_header' ERROR: "gre_parse_header" [net/ipv6/ip6_gre.ko] undefined! This adds a Kconfig dependency to prevent that now invalid configuration. Signed-off-by: Arnd Bergmann <a...@arndb.de> Fixes: 308edfdf1563 ("gre6: Cleanup GREv6 receive path, call common GRE functions") --- net/ipv6/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig index 11e875ffd7ac..3f8411328de5 100644 --- a/net/ipv6/Kconfig +++ b/net/ipv6/Kconfig @@ -218,6 +218,7 @@ config IPV6_GRE tristate "IPv6: GRE tunnel" select IPV6_TUNNEL select NET_IP_TUNNEL + depends on NET_IPGRE_DEMUX ---help--- Tunneling means encapsulating data of one protocol type within another protocol and sending it over a channel that understands the -- 2.7.0