Bug#1016586: bpftool: Dump of jited version of the BPF program requires libbfd support

[Emmanuel Fleury]

Package: bpftool
Version: 6.8.0+5.18.14-1
Severity: normal

Dear Maintainer,



Here is the content of the minimalist BPF program:

==============================
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>

SEC("socket")
int bpf_prog (struct __sk_buff *skb)
{
  return 1;
}
==============================

Built with:

#> clang -target bpf -o basic.o -c basic.c

Inserted and pinned:

#(root)> bpftool prog load basic.o /sys/fs/bpf/bar

Checking that it is present in the loaded BPF programs:

#(root)> bpftool prog list

...
37: type 31  name bpf_prog  tag cba989f8e5d0e900
        loaded_at 2022-08-02T16:31:18+0200  uid 0
        xlated 24B  jited 29B  memlock 4096B


Dump the BPF format:

#(root)> bpftool prog dump xlated id 37
   0: (7b) *(u64 *)(r10 -8) = r1
   1: (b7) r0 = 1
   2: (95) exit


Attempt to dump the jitted format:

#(root)> bpftool prog dump jited pinned /sys/fs/bpf/foo

Error: No libbfd support




Feel free to ask for more details if I was not clear in my report.


-- System Information:
Debian Release: bookworm/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.18.0-3-amd64 (SMP w/8 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:\
en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages bpftool depends on:
ii  libc6    2.33-8
ii  libcap2  1:2.44-1
ii  libelf1  0.187-1
ii  zlib1g   1:1.2.11.dfsg-4

bpftool recommends no packages.

bpftool suggests no packages.

-- no debconf information

I was trying to dump the jited version of a BPF program that was pinned in /sys/fs/bpf but I received a warning about libbpf that it wasn't supported. I suppose that the support for BPF must be add to libbfd in the binutils-dev package by default.

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