On Tue, Mar 10, 2020 at 7:12 PM Quentin Monnet <quentin@xxxxxxxxxxxxx> wrote:
>
> In commit 4a3d6c6a6e4d ("libbpf: Reduce log level for custom section
> names"), log level for messages for libbpf_attach_type_by_name() and
> libbpf_prog_type_by_name() was downgraded from "info" to "debug". The
> latter function, in particular, is used by bpftool when attempting to
> load programs, and this change caused bpftool to exit with no hint or
> error message when it fails to detect the type of the program to load
> (unless "-d" option was provided).
>
> To help users understand why bpftool fails to load the program, let's do
> a second run of the function with log level in "debug" mode in case of
> failure.
>
> Before:
>
> # bpftool prog load sample_ret0.o /sys/fs/bpf/sample_ret0
> # echo $?
> 255
>
> Or really verbose with -d flag:
>
> # bpftool -d prog load sample_ret0.o /sys/fs/bpf/sample_ret0
> libbpf: loading sample_ret0.o
> libbpf: section(1) .strtab, size 134, link 0, flags 0, type=3
> libbpf: skip section(1) .strtab
> libbpf: section(2) .text, size 16, link 0, flags 6, type=1
> libbpf: found program .text
> libbpf: section(3) .debug_abbrev, size 55, link 0, flags 0, type=1
> libbpf: skip section(3) .debug_abbrev
> libbpf: section(4) .debug_info, size 75, link 0, flags 0, type=1
> libbpf: skip section(4) .debug_info
> libbpf: section(5) .rel.debug_info, size 32, link 14, flags 0, type=9
> libbpf: skip relo .rel.debug_info(5) for section(4)
> libbpf: section(6) .debug_str, size 150, link 0, flags 30, type=1
> libbpf: skip section(6) .debug_str
> libbpf: section(7) .BTF, size 155, link 0, flags 0, type=1
> libbpf: section(8) .BTF.ext, size 80, link 0, flags 0, type=1
> libbpf: section(9) .rel.BTF.ext, size 32, link 14, flags 0, type=9
> libbpf: skip relo .rel.BTF.ext(9) for section(8)
> libbpf: section(10) .debug_frame, size 40, link 0, flags 0, type=1
> libbpf: skip section(10) .debug_frame
> libbpf: section(11) .rel.debug_frame, size 16, link 14, flags 0, type=9
> libbpf: skip relo .rel.debug_frame(11) for section(10)
> libbpf: section(12) .debug_line, size 74, link 0, flags 0, type=1
> libbpf: skip section(12) .debug_line
> libbpf: section(13) .rel.debug_line, size 16, link 14, flags 0, type=9
> libbpf: skip relo .rel.debug_line(13) for section(12)
> libbpf: section(14) .symtab, size 96, link 1, flags 0, type=2
> libbpf: looking for externs among 4 symbols...
> libbpf: collected 0 externs total
> libbpf: failed to guess program type from ELF section '.text'
> libbpf: supported section(type) names are: socket sk_reuseport kprobe/ [...]
>
> After:
>
> # bpftool prog load sample_ret0.o /sys/fs/bpf/sample_ret0
> libbpf: failed to guess program type from ELF section '.text'
> libbpf: supported section(type) names are: socket sk_reuseport kprobe/ [...]
>
> Signed-off-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
Applied. Thanks
