------- Comment From i...@de.ibm.com 2020-08-04 18:45 EDT-------
Hi,
I fixed the skydive header as follows:
--- a/ebpf/defs.h
+++ b/ebpf/defs.h
@@ -56,7 +56,7 @@ static __inline int discret_memcmp(char *s1, char *s2, int n)
/* helper marcro to define a map, socket, kprobe section in the
* eBPF elf file.
*/
-#define MAP(NAME) struct bpf_map_def __section("maps/" #NAME) NAME =
+#define MAP(NAME) struct bpf_map_def __section("maps") NAME =
#define SOCKET(NAME) __section("socket_" #NAME)
#define LICENSE __section("license")
and also tried to cherry-pick some of the older kernel patches I wrote, e.g.:
https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=88aa8939c96781089e5ace3492d818074c5c6fe9
https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=05a68e892e89c97df6650cd8cc55058002657cbc
https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=3f161e0ae863a0456d00e5a6c9c81098c62ab7fe
- the new ones I linked here fix samples and aren't relevant for skydive
- but then I found out that quite some common code is missing as well.
For example, on 20.04 LLVM 10 is default. It contains the following
commit:
commit fbb64aa69835c8e3e9efe0afc8a73058b5a0fb3c # llvmorg-10.0.0
Author: Yonghong Song <y...@fb.com>
Date: Tue Dec 17 16:24:23 2019 -0800
[BPF] extend BTF_KIND_FUNC to cover global, static and extern funcs
which makes clang produce non-backwards-compatible BTF. This leads to:
[14] FUNC bpf_flow_table type_id=12 vlen != 0
libbpf: Error loading .BTF into kernel: -22.
when loading. It's not that BPF devs did not think about this: in case
kernel cannot handle the new BTF_KIND_FUNC bits, they are supposed to be
sanitized by libbpf. However, Ubuntu 20.04 does not ship the newest
libbpf:
# /usr/sbin/bpftool --version
/usr/lib/linux-tools/5.4.0-42-generic/bpftool v5.4.44
whereas the commit that introduced sanitization is in v5.6:
commit 2d3eb67f64ec317bbfe340cfcc8325d40a6ff317 # v5.6
Author: Alexei Starovoitov <a...@kernel.org>
Date: Thu Jan 9 22:41:19 2020 -0800
libbpf: Sanitize global functions
Since this now turns into quite an adventure w.r.t. backporting, can't
we try an easier path first? Namely: use clang-8, which is also
available in Ubuntu 20.04, but doesn't include any fancy stuff!
skydive# CLANG=clang-8 GOPATH=$HOME/go make -C ebpf
skydive# bpftool prog load ebpf/flow.o /sys/fs/bpf/flow ; echo $?
0
# bpftool prog load ebpf/flow-gre.o /sys/fs/bpf/flow-gre ; echo $?
0
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https://bugs.launchpad.net/bugs/1888507
Title:
[UBUNTU 18.04] BPF programs fail on Ubuntu s390x
Status in Ubuntu on IBM z Systems:
In Progress
Status in linux package in Ubuntu:
New
Status in linux source package in Bionic:
In Progress
Bug description:
We need to run BPF filters to analyse and monitor network traffic. The
BPF filters are created by skydive (http://skydive.network). Currently
skydive fails to install BPF filters on s390x (using Ubuntu 18.04
currently, soon moving to Ubuntu 20.04).
Because of these failures, we decided to try the BPF samples that come
with the kernel first. These samples also fail on s390x while they
work fine on Intel.
shense@boe-build:~/bionic/samples/bpf$ uname -a
Linux boe-build 4.15.0-112-generic #113-Ubuntu SMP Thu Jul 9 23:40:36 UTC
2020 s390x s390x s390x GNU/Linux
Example instructions:
sudo apt install -y dpkg-dev clang llvm libelf-dev
sudo apt-get source linux-image-unsigned-$(uname -r)
cd linux-4.15.0/
make headers_install
make samples/bpf/
Errors:
shense@boe-build:~/bionic/samples/bpf$ sudo ./test_map_in_map
[sudo] password for shense:
invalid relo for insn[4].code 0x85
bpf_load_program() err=22
0: (bf) r7 = r1
1: (b7) r1 = 0
2: (63) *(u32 *)(r10 -32) = r1
3: (bf) r1 = r7
4: (85) call unknown#-1
BPF_CALL uses reserved fields
0: (bf) r7 = r1
1: (b7) r1 = 0
2: (63) *(u32 *)(r10 -32) = r1
3: (bf) r1 = r7
4: (85) call unknown#-1
BPF_CALL uses reserved fields
shense@boe-build:~/bionic/samples/bpf$ sudo ./map_perf_test
invalid relo for insn[22].code 0x85
bpf_load_program() err=22
0: (bf) r7 = r1
1: (18) r1 = 0x207265743a25646e
3: (7b) *(u64 *)(r10 -16) = r1
4: (18) r1 = 0x705f616c6c6f632e
6: (7b) *(u64 *)(r10 -24) = r1
7: (18) r1 = 0x5f6c72755f686d61
9: (7b) *(u64 *)(r10 -32) = r1
10: (18) r1 = 0x7420737472657373
12: (7b) *(u64 *)(r10 -40) = r1
13: (18) r1 = 0x4661696c65642061
15: (7b) *(u64 *)(r10 -48) = r1
16: (b7) r1 = 0
17: (73) *(u8 *)(r10 -8) = r1
18: (b7) r2 = 1
19: (7b) *(u64 *)(r10 -72) = r2
20: (63) *(u32 *)(r10 -76) = r1
21: (bf) r1 = r7
22: (85) call unknown#-1
BPF_CALL uses reserved fields
0: (bf) r7 = r1
1: (18) r1 = 0x207265743a25646e
3: (7b) *(u64 *)(r10 -16) = r1
4: (18) r1 = 0x705f616c6c6f632e
6: (7b) *(u64 *)(r10 -24) = r1
7: (18) r1 = 0x5f6c72755f686d61
9: (7b) *(u64 *)(r10 -32) = r1
10: (18) r1 = 0x7420737472657373
12: (7b) *(u64 *)(r10 -40) = r1
13: (18) r1 = 0x4661696c65642061
15: (7b) *(u64 *)(r10 -48) = r1
16: (b7) r1 = 0
17: (73) *(u8 *)(r10 -8) = r1
18: (b7) r2 = 1
19: (7b) *(u64 *)(r10 -72) = r2
20: (63) *(u32 *)(r10 -76) = r1
21: (bf) r1 = r7
22: (85) call unknown#-1
BPF_CALL uses reserved fields
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