failed to run kprobe example on arm64

[setNull]

Hi team,

I failed to run kprobe example n arm64 as below,

root@tegra-ubuntu:/ota# ./kprobe -v
libbpf: loading object 'kprobe_bpf' from buffer
libbpf: elf: section(2) kprobe/do_unlinkat, size 152, link 0, flags 6, type=1
libbpf: sec 'kprobe/do_unlinkat': found program 'do_unlinkat' at insn offset 0 (0 bytes), code size 19 insns (152 bytes)
libbpf: elf: section(3) kretprobe/do_unlinkat, size 88, link 0, flags 6, type=1
libbpf: sec 'kretprobe/do_unlinkat': found program 'do_unlinkat_exit' at insn offset 0 (0 bytes), code size 11 insns (88 bytes)
libbpf: elf: section(4) license, size 13, link 0, flags 3, type=1
libbpf: license of kprobe_bpf is Dual BSD/GPL
libbpf: elf: section(5) .rodata, size 72, link 0, flags 2, type=1
libbpf: elf: section(6) .BTF, size 1467, link 0, flags 0, type=1
libbpf: elf: section(7) .BTF.ext, size 364, link 0, flags 0, type=1
libbpf: elf: section(8) .symtab, size 240, link 14, flags 0, type=2
libbpf: elf: section(9) .relkprobe/do_unlinkat, size 16, link 8, flags 0, type=9
libbpf: elf: section(10) .relkretprobe/do_unlinkat, size 16, link 8, flags 0, type=9
libbpf: looking for externs among 10 symbols...
libbpf: collected 0 externs total
libbpf: map 'kprobe_b.rodata' (global data): at sec_idx 5, offset 0, flags 480.
libbpf: map 0 is "kprobe_b.rodata"
libbpf: sec '.relkprobe/do_unlinkat': collecting relocation for section(2) 'kprobe/do_unlinkat'
libbpf: sec '.relkprobe/do_unlinkat': relo #0: insn #12 against '.rodata'
libbpf: prog 'do_unlinkat': found data map 0 (kprobe_b.rodata, sec 5, off 0) for insn 12
libbpf: sec '.relkretprobe/do_unlinkat': collecting relocation for section(3) 'kretprobe/do_unlinkat'
libbpf: sec '.relkretprobe/do_unlinkat': relo #0: insn #3 against '.rodata'
libbpf: prog 'do_unlinkat_exit': found data map 0 (kprobe_b.rodata, sec 5, off 0) for insn 3
libbpf: loading kernel BTF '/sys/kernel/btf/vmlinux': 0
libbpf: map 'kprobe_b.rodata': created successfully, fd=4
libbpf: sec 'kprobe/do_unlinkat': found 2 CO-RE relocations
libbpf: CO-RE relocating [2] struct pt_regs: found target candidate [248] struct pt_regs in [vmlinux]
libbpf: prog 'do_unlinkat': relo #0: <byte_off> [2] struct pt_regs.si (0:13 @ offset 104)
libbpf: prog 'do_unlinkat': relo #0: non-matching candidate #0 <byte_off> [248] struct pt_regs (0 @ offset 0)
libbpf: prog 'do_unlinkat': relo #0: no matching targets found
libbpf: prog 'do_unlinkat': relo #0: substituting insn #0 w/ invalid insn
libbpf: CO-RE relocating [7] struct filename: found target candidate [1173] struct filename in [vmlinux]
libbpf: prog 'do_unlinkat': relo #1: <byte_off> [7] struct filename.name (0:0 @ offset 0)
libbpf: prog 'do_unlinkat': relo #1: matching candidate #0 <byte_off> [1173] struct filename.name (0:0 @ offset 0)
libbpf: prog 'do_unlinkat': relo #1: patched insn #3 (ALU/ALU64) imm 0 -> 0
libbpf: sec 'kretprobe/do_unlinkat': found 1 CO-RE relocations
libbpf: prog 'do_unlinkat_exit': relo #0: <byte_off> [2] struct pt_regs.ax (0:10 @ offset 80)
libbpf: prog 'do_unlinkat_exit': relo #0: non-matching candidate #0 <byte_off> [248] struct pt_regs (0 @ offset 0)
libbpf: prog 'do_unlinkat_exit': relo #0: no matching targets found
libbpf: prog 'do_unlinkat_exit': relo #0: substituting insn #0 w/ invalid insn
libbpf: prog 'do_unlinkat': BPF program load failed: Invalid argument
libbpf: prog 'do_unlinkat': -- BEGIN PROG LOAD LOG --
Unrecognized arg#0 type PTR
; int BPF_KPROBE(do_unlinkat, int dfd, struct filename *name)
0: <invalid CO-RE relocation>
failed to resolve CO-RE relocation <byte_off> [2] struct pt_regs.si (0:13 @ offset 104)
processed 1 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
-- END PROG LOAD LOG --
libbpf: failed to load program 'do_unlinkat'
libbpf: failed to load object 'kprobe_bpf'
libbpf: failed to load BPF skeleton 'kprobe_bpf': -22
Failed to open BPF skeleton

Cound someone point out what's wrong here? Thanks.

[ThinkerYzu1]

Looks like you build kprobe.bpf.c, a bpf program, for x86. Did you build the example on an ARM64 device? Or, you did cross-compiling?

[setNull]

Looks like you build kprobe.bpf.c, a bpf program, for x86. Did you build the example on an ARM64 device? Or, you did cross-compiling?

Hi @ThinkerYzu1 ,

Thanks for your reply.
Yes, I cross-compiling the example for ARM64.
I resolved this issue by adding ARCH=arm64 in make command line(while previously declare it in ENV not work).