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Date: Mon, 3 Jun 2024 21:18:33 +0200
From: Mark Wielaard <mark@klomp.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Tony Ambardar <tony.ambardar@gmail.com>, Mark Wielaard <mjw@redhat.com>,
	Hengqi Chen <hengqi.chen@gmail.com>, bpf@vger.kernel.org,
	dwarves@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>
Subject: Re: elfutils DWARF problem was: Re: Problem with BTF generation on
 mips64el
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User-Agent: Mutt/1.5.21 (2010-09-15)

Hi,

On Mon, Jun 03, 2024 at 02:40:45PM -0300, Arnaldo Carvalho de Melo wrote:
> Couldn't find a way to ask eu-readelf for more verbose output, where we
> could perhaps get some clue as to why it produces nothing while binutils
> readelf manages to grok it, Mark, do you know some other way to ask
> eu-readelf to produce more debug output?
> 
> I'm unsure if the netdevsim.ko file was left in a semi encoded BTF state
> that then made eu-readelf to not be able to process it while pahole,
> that uses eltuils' libraries, was able to process the first two CUs for
> a kernel module and all the CUs for the vmlinux file :-\

I haven't looked at the vmlinux file. But for the .ko file the issue
is that the elfutils MIPS backend isn't complete. Specifically MIPS
relocations aren't recognized (and so cannot be applied). There are
some pending patches which try to fix that:

https://patchwork.sourceware.org/project/elfutils/list/?series=31601

Cheers,

Mark