Debug info is missing

[ikalchev]

Hi everyone,

I am writing a perf_event probe and I am using aya-bpf and the bpf-linker. I've used the blueprint build "scripts" from Aya. When I was trying to debug some BPF verifier errors, I tried to get more info on the generated byte code using:

llvm-objdump-16 -S --no-show-raw-insn --section=perf_event target/bpfel-unknown-none/debug/my-bin

However, this does not print the source code, just the byte code:

$ llvm-objdump-16 --source --no-show-raw-insn --section=perf_event target/bpfel-unknown-none/debug/my-bin

target/bpfel-unknown-none/debug/my-bin:	file format elf64-bpf

Disassembly of section perf_event:

0000000000000000 <decode_frame>:
       0:	r6 = r1
       1:	r1 = 0x0
       2:	*(u32 *)(r10 - 0x4) = r1
       3:	r2 = r10
       4:	r2 += -0x4
       5:	r1 = 0x0 ll

I then checked if the binary has debug info at all. Since it didn't, I then changed the Cargo.toml for the ebpf code to have debug = true, but this didn't help as well.

file target/bpfel-unknown-none/debug/my-bin
target/bpfel-unknown-none/debug/my-bin: ELF 64-bit LSB relocatable, eBPF, version 1 (SYSV), not stripped

This is happens on:

$ uname -a
Linux xdp-test 6.2.0-37-generic #38~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Nov  2 22:07:48 UTC 2 aarch64 aarch64 aarch64 GNU/Linux

(this is a VM running on a macOS on arm).

Cargo and rustc are on 1.73, Aya is pulled directly from github.

Any idea on what might be wrong?

[ikalchev]

I guess this is why? aya-rs/aya#351

Can someone confirm so we can close this?

[dave-tucker]

Sorry for the delay. Yes that's partially correct.
eBPF Debug Info is in the BTF.ext section.
Once #182 merges I believe verifier output should include source info - if you use the --btf option that is 🎉
We'll get that documented so it's easy to use.