On 10/26/2016 03:17 AM, Alexei Starovoitov wrote:
On Wed, Oct 26, 2016 at 12:37:53AM +0200, Daniel Borkmann wrote:
Some of the sample files are causing issues when they are loaded with tc
and cls_bpf, meaning tc bails out while trying to parse the resulting ELF
file as program/map/etc sections are not present, which can be easily
spotted with readelf(1).
Currently, BPF samples are including some of the kernel headers and mid
term we should change them to refrain from this, really. When dynamic
debugging is enabled, we bail out due to undeclared KBUILD_MODNAME, which
is easily overlooked in the build as clang spills this along with other
noisy warnings from various header includes, and llc still generates an
ELF file with mentioned characteristics. For just playing around with BPF
examples, this can be a bit of a hurdle to take.
Just add a fake KBUILD_MODNAME as a band-aid to fix the issue, same is
done in xdp*_kern samples already.
Fixes: 65d472fb007d ("samples/bpf: add 'pointer to packet' tests")
Fixes: 6afb1e28b859 ("samples/bpf: Add tunnel set/get tests.")
Fixes: a3f74617340b ("cgroup: bpf: Add an example to do cgroup checking in BPF")
Reported-by: Chandrasekar Kannan <ckan...@console.to>
Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
---
samples/bpf/parse_ldabs.c | 1 +
samples/bpf/parse_simple.c | 1 +
samples/bpf/parse_varlen.c | 1 +
samples/bpf/tcbpf1_kern.c | 1 +
samples/bpf/tcbpf2_kern.c | 1 +
samples/bpf/test_cgrp2_tc_kern.c | 1 +
6 files changed, 6 insertions(+)
It's also needed for all of tracex*_kern.c, right?
Rest compiles just fine for me and readelf output looks good on all
tracex*_kern.o, too.
I see just warnings coming from various kernel header inclusions (see
log), but no errors anymore.
/home/darkstar/net/samples/bpf/trace_output_user.c:64:6: warning: no previous
prototype for ‘perf_event_read’ [-Wmissing-prototypes]
void perf_event_read(print_fn fn)
^
In file included from /home/darkstar/net/samples/bpf/sockex2_kern.c:8:
In file included from ./include/uapi/linux/if_tunnel.h:6:
In file included from ./include/linux/ip.h:20:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/sockex2_kern.c:8:
In file included from ./include/uapi/linux/if_tunnel.h:6:
In file included from ./include/linux/ip.h:20:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/sockex3_kern.c:14:
In file included from ./include/uapi/linux/if_tunnel.h:6:
In file included from ./include/linux/ip.h:20:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/sockex3_kern.c:14:
In file included from ./include/uapi/linux/if_tunnel.h:6:
In file included from ./include/linux/ip.h:20:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/tracex1_kern.c:7:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/tracex1_kern.c:7:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/tracex2_kern.c:7:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/tracex2_kern.c:7:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/tracex3_kern.c:7:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/tracex3_kern.c:7:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/tracex4_kern.c:7:
In file included from ./include/linux/ptrace.h:5:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
1 warning generated.
In file included from /home/darkstar/net/samples/bpf/tracex5_kern.c:7:
In file included from ./include/linux/ptrace.h:5:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
1 warning generated.
In file included from /home/darkstar/net/samples/bpf/tracex6_kern.c:1:
In file included from ./include/linux/ptrace.h:5:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
1 warning generated.
In file included from
/home/darkstar/net/samples/bpf/test_probe_write_user_kern.c:7:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from
/home/darkstar/net/samples/bpf/test_probe_write_user_kern.c:7:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/trace_output_kern.c:1:
In file included from ./include/linux/ptrace.h:5:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
1 warning generated.
In file included from /home/darkstar/net/samples/bpf/tcbpf2_kern.c:18:
In file included from ./include/net/ipv6.h:16:
In file included from ./include/linux/ipv6.h:76:
In file included from ./include/linux/icmpv6.h:4:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/tcbpf2_kern.c:18:
In file included from ./include/net/ipv6.h:16:
In file included from ./include/linux/ipv6.h:76:
In file included from ./include/linux/icmpv6.h:4:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/lathist_kern.c:9:
In file included from ./include/linux/ptrace.h:5:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
1 warning generated.
In file included from /home/darkstar/net/samples/bpf/offwaketime_kern.c:12:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
1 warning generated.
In file included from /home/darkstar/net/samples/bpf/spintest_kern.c:7:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/spintest_kern.c:7:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/map_perf_test_kern.c:7:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/map_perf_test_kern.c:7:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from
/home/darkstar/net/samples/bpf/test_overhead_kprobe_kern.c:8:
In file included from ./include/linux/ptrace.h:5:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
1 warning generated.
In file included from /home/darkstar/net/samples/bpf/parse_varlen.c:8:
In file included from ./include/linux/if_ether.h:23:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/parse_varlen.c:8:
In file included from ./include/linux/if_ether.h:23:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/parse_simple.c:8:
In file included from ./include/linux/ip.h:20:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/parse_simple.c:8:
In file included from ./include/linux/ip.h:20:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/parse_ldabs.c:8:
In file included from ./include/linux/ip.h:20:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/parse_ldabs.c:8:
In file included from ./include/linux/ip.h:20:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/xdp1_kern.c:10:
In file included from ./include/linux/if_ether.h:23:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/xdp1_kern.c:10:
In file included from ./include/linux/if_ether.h:23:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from /home/darkstar/net/samples/bpf/xdp2_kern.c:10:
In file included from ./include/linux/if_ether.h:23:
In file included from ./include/linux/skbuff.h:29:
In file included from ./include/linux/net.h:28:
./include/linux/fs.h:2693:9: warning: comparison of unsigned enum expression <
0 is always false [-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
In file included from /home/darkstar/net/samples/bpf/xdp2_kern.c:10:
In file included from ./include/linux/if_ether.h:23:
In file included from ./include/linux/skbuff.h:30:
In file included from ./include/linux/textsearch.h:8:
In file included from ./include/linux/slab.h:118:
In file included from ./include/linux/kasan.h:4:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
2 warnings generated.
In file included from
/home/darkstar/net/samples/bpf/test_current_task_under_cgroup_kern.c:8:
In file included from ./include/linux/ptrace.h:5:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
1 warning generated.
In file included from /home/darkstar/net/samples/bpf/trace_event_kern.c:7:
In file included from ./include/linux/ptrace.h:5:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
1 warning generated.
In file included from /home/darkstar/net/samples/bpf/sampleip_kern.c:8:
In file included from ./include/linux/ptrace.h:5:
In file included from ./include/linux/sched.h:61:
./include/linux/cgroup-defs.h:322:16: warning: field 'cgrp' with variable sized
type 'struct cgroup' not at the end of a struct or class is a GNU extension
[-Wgnu-variable-sized-type-not-at-end]
struct cgroup cgrp;
^
1 warning generated.
