Messages in this thread | | | Subject | Re: [PATCH bpf-next 1/2] bpf: Remove bpf_jit_enable=2 debugging mode | From | Christophe Leroy <> | Date | Fri, 14 May 2021 08:34:07 +0200 |
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Le 23/04/2021 à 12:26, Quentin Monnet a écrit : > 2021-04-23 09:19 UTC+0200 ~ Christophe Leroy <christophe.leroy@csgroup.eu> > > [...] > >> I finally managed to cross compile bpftool with libbpf, libopcodes, >> readline, ncurses, libcap, libz and all needed stuff. Was not easy but I >> made it. > > Libcap is optional and bpftool does not use readline or ncurses. May I > ask how you tried to build it? > >> >> Now, how do I use it ? >> >> Let say I want to dump the jitted code generated from a call to >> 'tcpdump'. How do I do that with 'bpftool prog dump jited' ? >> >> I thought by calling this line I would then get programs dumped in a way >> or another just like when setting 'bpf_jit_enable=2', but calling that >> line just provides me some bpftool help text. > > Well the purpose of this text is to help you find the way to call > bpftool to do what you want :). For dumping your programs' instructions, > you need to tell bpftool what program to dump: Bpftool isn't waiting > until you load a program to dump it, instead you need to load your > program first and then tell bpftool to retrieve the instructions from > the kernel. To reference your program you could use a pinned path, or > first list the programs on your system with "bpftool prog show": > > > # bpftool prog show > 138: tracing name foo tag e54c922dfa54f65f gpl > loaded_at 2021-02-25T01:32:30+0000 uid 0 > xlated 256B jited 154B memlock 4096B map_ids 64 > btf_id 235
Got the following error:
root@vgoip:~# ./bpftool prog show libbpf: elf: endianness mismatch in pid_iter_bpf. libbpf: failed to initialize skeleton BPF object 'pid_iter_bpf': -4003 Error: failed to open PID iterator skeleton
Christophe
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