From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: John Fastabend <john.fastabend@gmail.com>
Cc: Eelco Chaudron <echaudro@redhat.com>, Yonghong Song <yhs@fb.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Xdp <xdp-newbies@vger.kernel.org>, bpf <bpf@vger.kernel.org>
Subject: Re: Trying the bpf trace a bpf xdp program
Date: Wed, 4 Dec 2019 13:19:21 -0800 [thread overview]
Message-ID: <CAEf4BzaorvXOcunEg7CPYmeFhWzAg14dOaj10kVxzc9pnoXiLw@mail.gmail.com> (raw)
In-Reply-To: <5de7f5057f957_96d2b0feaf1e5bc19@john-XPS-13-9370.notmuch>
On Wed, Dec 4, 2019 at 10:03 AM John Fastabend <john.fastabend@gmail.com> wrote:
>
> Andrii Nakryiko wrote:
> > On Wed, Dec 4, 2019 at 5:20 AM Eelco Chaudron <echaudro@redhat.com> wrote:
> > >
>
> [...]
>
> > >
> > > PS: If I run the latest pahole (v1.15) on the .o files, I get the
> > > following libbpf error: “libbpf: Cannot find bpf_func_info for main
> > > program sec fexit/xdp_prog_simple. Ignore all bpf_func_info.”
> > >
> >
> > pahole is not supposed to be run on BPF object file. It's needed only
> > to do DWARF to BTF conversion for kernel itself. So never mind this
> > one. The NULL dereference, though, seems like a bug, I agree with
> > Yonghong.
>
> Really? I've been using pahole on BPF object files regularly mostly
> to test structures match up with kernel pahole output but its always
> worked on my side. Even pahole -j seems to work fine here.
Well, it still works for simpler stuff, but it certainly won't emit
global variables type info, CO-RE relocations, etc. BTF for BPF object
files should get produced by Clang, which is perfectly capable of
doing this (provided you have recent enough version of it, of course).
prev parent reply other threads:[~2019-12-04 21:19 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <E53E0693-1C3A-4B47-B205-DC8E5DAF3619@redhat.com>
2019-11-28 18:18 ` Trying the bpf trace a bpf xdp program Alexei Starovoitov
2019-11-28 19:16 ` Eelco Chaudron
2019-11-28 19:47 ` Alexei Starovoitov
2019-11-29 16:30 ` Eelco Chaudron
2019-11-29 16:52 ` Yonghong Song
2019-12-02 16:34 ` Eelco Chaudron
2019-12-02 16:48 ` Yonghong Song
2019-12-04 13:19 ` Eelco Chaudron
2019-12-04 14:58 ` Yonghong Song
2019-12-04 18:01 ` Yonghong Song
2019-12-04 18:52 ` Eelco Chaudron
2019-12-05 12:40 ` Eelco Chaudron
2019-12-05 17:35 ` Y Song
2019-12-06 13:04 ` Eelco Chaudron
2019-12-07 16:51 ` Alexei Starovoitov
2019-12-19 11:06 ` Eelco Chaudron
2019-12-04 16:31 ` Andrii Nakryiko
2019-12-04 18:03 ` John Fastabend
2019-12-04 21:19 ` Andrii Nakryiko [this message]
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