BPF Archive on lore.kernel.org
 help / color / Atom feed
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
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).

      reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <E53E0693-1C3A-4B47-B205-DC8E5DAF3619@redhat.com>
2019-11-28 18:18 ` 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
2019-12-04 16:31                 ` Andrii Nakryiko
2019-12-04 18:03                   ` John Fastabend
2019-12-04 21:19                     ` Andrii Nakryiko [this message]

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAEf4BzaorvXOcunEg7CPYmeFhWzAg14dOaj10kVxzc9pnoXiLw@mail.gmail.com \
    --to=andrii.nakryiko@gmail.com \
    --cc=alexei.starovoitov@gmail.com \
    --cc=bpf@vger.kernel.org \
    --cc=echaudro@redhat.com \
    --cc=john.fastabend@gmail.com \
    --cc=xdp-newbies@vger.kernel.org \
    --cc=yhs@fb.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

BPF Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/bpf/0 bpf/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 bpf bpf/ https://lore.kernel.org/bpf \
		bpf@vger.kernel.org
	public-inbox-index bpf

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.bpf


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git