In Linux 4.5, when CONFIG_NET_CLS_ACT is defined, compilation of out of
tree modules breaks with undeclared functions/constants. The culprit is:
commit fdc5432a7b44ab7de17141beec19d946b9344e91
Author: Daniel Borkmann <[email protected]>
Date: Thu Jan 7 15:50:22 2016 +0100
net, sched: add skb_at_tc_ingress helper
which uses G_TC_AT and AT_INGRESS but only includes linux/pkt_cls.h,
which does not include these #defines for oot builds. Unfortunately I'm
not sure what the correct fix is, maybe the uapi folks could help, but i
attached a simple testcase and build log (Makefile is straight from
kernelnewbies).
Ingo
--
╭─╮ Kennedy's Lemma:
╭│───╮ If you can parse Perl, you can solve the Halting Problem.
│╰─│─╯
╰──╯ http://www.perlmonks.org/?node_id=663393
#include <net/ipv6.h>
obj-m := fail.o
all:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
clean:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
make -C /lib/modules/4.5.0-pinguin20160314/build
M=/home/ingo/src/linux/pkt_cls-bug modules
make[1]: Entering directory '/usr/src/linux-headers-4.5.0-pinguin20160314'
CC [M] /home/ingo/src/linux/pkt_cls-bug/fail.o
In file included from include/linux/filter.h:16:0,
from include/net/sock.h:64,
from include/linux/tcp.h:22,
from include/linux/ipv6.h:72,
from include/net/ipv6.h:16,
from /home/ingo/src/linux/pkt_cls-bug/fail.c:1:
include/net/sch_generic.h: In function ‘skb_at_tc_ingress’:
include/net/sch_generic.h:413:9: error: implicit declaration of function
‘G_TC_AT’ [-Werror=implicit-function-declaration]
return G_TC_AT(skb->tc_verd) & AT_INGRESS;
^
include/net/sch_generic.h:413:33: error: ‘AT_INGRESS’ undeclared (first use in
this function)
return G_TC_AT(skb->tc_verd) & AT_INGRESS;
^
include/net/sch_generic.h:413:33: note: each undeclared identifier is reported
only once for each function it appears in
cc1: some warnings being treated as errors
scripts/Makefile.build:264: recipe for target
'/home/ingo/src/linux/pkt_cls-bug/fail.o' failed
make[2]: *** [/home/ingo/src/linux/pkt_cls-bug/fail.o] Error 1
Makefile:1391: recipe for target '_module_/home/ingo/src/linux/pkt_cls-bug'
failed
make[1]: *** [_module_/home/ingo/src/linux/pkt_cls-bug] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-4.5.0-pinguin20160314'
Makefile:4: recipe for target 'all' failed
make: *** [all] Error 2
