On Dec 6, 2021, at 4:32 AM, Arnaldo Carvalho de Melo [off-list ref] wrote:

Em Fri, Dec 03, 2021 at 08:05:59PM +0000, Song Liu escreveu:

quoted

quoted

On Dec 3, 2021, at 5:28 AM, Arnaldo Carvalho de Melo [off-list ref] wrote:
The failure for fedora:32, which seems to be on the threshold for clang
to be considered recent enough for building skels fails differently:

quoted

quoted

clang version 10.0.1 (Fedora 10.0.1-3.fc32)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-redhat-linux/10
Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/10
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-redhat-linux/10
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
+ '[' '!' ']'
+ rm -rf /tmp/build/perf
+ mkdir /tmp/build/perf
+ make ARCH= CROSS_COMPILE= EXTRA_CFLAGS= BUILD_BPF_SKEL=1 -C tools/perf O=/tmp/build/perf
make: Entering directory '/git/perf-5.16.0-rc3/tools/perf'
BUILD:   Doing 'make -j32' parallel build
HOSTCC  /tmp/build/perf/fixdep.o
HOSTLD  /tmp/build/perf/fixdep-in.o
LINK    /tmp/build/perf/fixdep
/bin/sh: -c: line 0: syntax error near unexpected token `('
/bin/sh: -c: line 0: `expr bison (GNU Bison) 3.5 \>\= 371'
Makefile.config:997: No libbabeltrace found, disables 'perf data' CTF format support, please install libbabeltrace-dev[el]/libbabeltrace-ctf-dev

Auto-detecting system features:
...                         dwarf: [ on  ]
...            dwarf_getlocations: [ on  ]
...                         glibc: [ on  ]
...                        libbfd: [ on  ]
...                libbfd-buildid: [ on  ]
...                        libcap: [ on  ]
...                        libelf: [ on  ]
...                       libnuma: [ on  ]
...        numa_num_possible_cpus: [ on  ]
...                       libperl: [ on  ]
...                     libpython: [ on  ]
...                     libcrypto: [ on  ]
...                     libunwind: [ on  ]
...            libdw-dwarf-unwind: [ on  ]
...                          zlib: [ on  ]
...                          lzma: [ on  ]
...                     get_cpuid: [ on  ]
...                           bpf: [ on  ]
...                        libaio: [ on  ]
...                       libzstd: [ on  ]
...        disassembler-four-args: [ on  ]

<SNIP>

quoted

quoted

GEN     /tmp/build/perf/util/bpf_skel/vmlinux.h
CLANG   /tmp/build/perf/util/bpf_skel/.tmp/bpf_prog_profiler.bpf.o
CLANG   /tmp/build/perf/util/bpf_skel/.tmp/bperf_leader.bpf.o
CLANG   /tmp/build/perf/util/bpf_skel/.tmp/bperf_follower.bpf.o
CLANG   /tmp/build/perf/util/bpf_skel/.tmp/bperf_cgroup.bpf.o
GENSKEL /tmp/build/perf/util/bpf_skel/bpf_prog_profiler.skel.h
GENSKEL /tmp/build/perf/util/bpf_skel/bperf_leader.skel.h
libbpf: elf: skipping unrecognized data section(9) .eh_frame
libbpf: elf: skipping relo section(15) .rel.eh_frame for section(9) .eh_frame
libbpf: elf: skipping unrecognized data section(7) .eh_frame
libbpf: elf: skipping relo section(12) .rel.eh_frame for section(7) .eh_frame
libbpf: map 'prev_readings': unexpected def kind var.
Error: failed to open BPF object file: Invalid argument
make[2]: *** [Makefile.perf:1076: /tmp/build/perf/util/bpf_skel/bperf_leader.skel.h] Error 255
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [Makefile.perf:240: sub-make] Error 2
make: *** [Makefile:70: all] Error 2
make: Leaving directory '/git/perf-5.16.0-rc3/tools/perf'
+ exit 1
[perfbuilder@five 32]$

Cc Andrii. 

Could you please try the fix below? 

If it doesn't work, could you please dump btf for debugging?

 bpftool btf dump file /tmp/build/perf/util/bpf_skel/.tmp/bperf_leader.bpf.o

It fixes the issue on Alpine Linux 3.12 and 3.13, Alt Linux p9 and fedora:32, probably others, still testing.

Can you please provide a cset commit log for me to stamp on it?

Please see the following commit log. 

Thanks,
Song

====================================== 8< ========================================

perf/bpf_skel: use vmlinux.h in skeletons

When building bpf_skel in perf on a system with older linux/bpf.h header,
we got errors like:

   util/bpf_skel/bperf_leader.bpf.c:13:20: error: use of undeclared
   identifier 'BPF_F_PRESERVE_ELEMS'
           __uint(map_flags, BPF_F_PRESERVE_ELEMS);

Fix this by using vmlinux.h instead. Also remove include of perf_event.h,
as it redefines structs in vmlinux.h.

Fixes: fa853c4b839e ("perf stat: Enable counting events for BPF programs")
Fixes: 7fac83aaf2ee ("perf stat: Introduce 'bperf' to share hardware PMCs with BPF")
Reported-by: Arnaldo Carvalho de Melo <redacted>
Tested-by: Athira Rajeev <redacted>
Signed-off-by: Song Liu <redacted>