Hi Jesper,
> On Jul 3, 2020, at 7:38 AM, Jesper Dangaard Brouer <brouer@xxxxxxxxxx> wrote:
>
> Hi Song,
>
> I' getting this compile error in tools/testing/selftests/bpf/ on
> bpf-next git tree with HEAD 046cc3dd9a25 ("bpf: Fix build without
> CONFIG_STACKTRACE"):
>
> $ pwd
> /home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf
> $ make
> Warning: Kernel ABI header at 'tools/include/uapi/linux/netlink.h' differs from latest version at 'include/uapi/linux/netlink.h'
> Warning: Kernel ABI header at 'tools/include/uapi/linux/if_link.h' differs from latest version at 'include/uapi/linux/if_link.h'
> INSTALL headers
> GEN-SKEL [test_progs] bpf_iter_task_stack.skel.h
> libbpf: invalid relo for 'entries' in special section 0xfff2; forgot to initialize global var?..
> Error: failed to open BPF object file: 0
> make: *** [Makefile:372: /home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/bpf_iter_task_stack.skel.h] Error 255
> make: *** Deleting file '/home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/bpf_iter_task_stack.skel.h'
Thanks for the report! Looks like there are some more checks in libbpf.
Sending a fix...
Song
>
>
> If I revert c7568114bc56 ("selftests/bpf: Add bpf_iter test with
> bpf_get_task_stack()") (Author: Song Liu) then it compiles again.
>
> --
> Best regards,
> Jesper Dangaard Brouer
> MSc.CS, Principal Kernel Engineer at Red Hat
> LinkedIn: https://urldefense.proofpoint.com/v2/url?u=http-3A__www.linkedin.com_in_brouer&d=DwICAg&c=5VD0RTtNlTh3ycd41b3MUw&r=dR8692q0_uaizy0jkrBJQM5k2hfm4CiFxYT8KaysFrg&m=e_FAl1at-_JkxvdBgN-A4MxYgcG7GCcILfqCfG2fwDg&s=AXys933GuyB-Gq6PGMRSjZsmJZt-tiDVvakHcNyaKAY&e=
>
> More details:
>
> $ clang --version
> clang version 10.0.0 (https://github.com/llvm/llvm-project.git 90c78073f73eac58f4f8b4772a896dc8aac023bc)
> Target: x86_64-unknown-linux-gnu
> Thread model: posix
> InstalledDir: /usr/local/bin
>
> llc --version
> LLVM (https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_&d=DwICAg&c=5VD0RTtNlTh3ycd41b3MUw&r=dR8692q0_uaizy0jkrBJQM5k2hfm4CiFxYT8KaysFrg&m=e_FAl1at-_JkxvdBgN-A4MxYgcG7GCcILfqCfG2fwDg&s=KCTx5PCpgbta-I0hnVe-MrEYLtM7WgACk_euEYjODLw&e= ):
> LLVM version 10.0.0git
> Optimized build.
> Default target: x86_64-unknown-linux-gnu
> Host CPU: ivybridge
>
> Registered Targets:
> bpf - BPF (host endian)
> bpfeb - BPF (big endian)
> bpfel - BPF (little endian)
> x86 - 32-bit X86: Pentium-Pro and above
> x86-64 - 64-bit X86: EM64T and AMD64
>
>
> make V=1
> (clang -g -D__TARGET_ARCH_x86 -mlittle-endian -I/home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/tools/include -I/home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf -I/home/jbrouer/git/kernel/bpf-next/tools/include/uapi -I/home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/usr/include -idirafter /usr/local/include -idirafter /usr/local/stow/llvm-10.0.0-rc2/lib/clang/10.0.0/include -idirafter /usr/include -Wno-compare-distinct-pointer-types -O2 -target bpf -emit-llvm -c progs/bpf_iter_task_stack.c -o - || echo "BPF obj compilation failed") | llc -mattr=dwarfris -march=bpf -mcpu=v3 -mattr=+alu32 -filetype=obj -o /home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/bpf_iter_task_stack.o
>
> /home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/tools/sbin/bpftool gen skeleton /home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/bpf_iter_task_stack.o > /home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/bpf_iter_task_stack.skel.h
> libbpf: invalid relo for 'entries' in special section 0xfff2; forgot to initialize global var?..
> Error: failed to open BPF object file: 0
> make: *** [Makefile:372: /home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/bpf_iter_task_stack.skel.h] Error 255
> make: *** Deleting file '/home/jbrouer/git/kernel/bpf-next/tools/testing/selftests/bpf/bpf_iter_task_stack.skel.h'
>
