From: Jiri Olsa <jolsa@redhat.com>
To: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
dwarves@vger.kernel.org, bpf@vger.kernel.org,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andriin@fb.com>, Yonghong Song <yhs@fb.com>,
Hao Luo <haoluo@google.com>, "Frank Ch. Eigler" <fche@redhat.com>,
Mark Wielaard <mjw@redhat.com>
Subject: Re: [PATCH 2/2] btf_encoder: Change functions check due to broken dwarf
Date: Mon, 2 Nov 2020 22:59:08 +0100 [thread overview]
Message-ID: <20201102215908.GC3597846@krava> (raw)
In-Reply-To: <20201031223131.3398153-3-jolsa@kernel.org>
On Sat, Oct 31, 2020 at 11:31:31PM +0100, Jiri Olsa wrote:
> We need to generate just single BTF instance for the
> function, while DWARF data contains multiple instances
> of DW_TAG_subprogram tag.
>
> Unfortunately we can no longer rely on DW_AT_declaration
> tag (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97060)
>
> Instead we apply following checks:
> - argument names are defined for the function
> - there's symbol and address defined for the function
> - function is generated only once
>
> Also because we want to follow kernel's ftrace traceable
> functions, this patchset is adding extra check that the
> function is one of the ftrace's functions.
>
> All ftrace functions addresses are stored in vmlinux
> binary within symbols:
> __start_mcount_loc
> __stop_mcount_loc
hum, for some reason this does not pass through bpf internal
functions like bpf_iter_bpf_map.. I learned it hard way ;-)
will check
jirka
next prev parent reply other threads:[~2020-11-02 21:59 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-31 22:31 [PATCHv2 0/2] pahole: Workaround dwarf bug for function encoding Jiri Olsa
2020-10-31 22:31 ` [PATCH 1/2] btf_encoder: Move find_all_percpu_vars in generic collect_symbols Jiri Olsa
2020-11-02 18:29 ` Hao Luo
2020-11-03 17:31 ` Arnaldo Carvalho de Melo
2020-10-31 22:31 ` [PATCH 2/2] btf_encoder: Change functions check due to broken dwarf Jiri Olsa
2020-11-02 21:59 ` Jiri Olsa [this message]
2020-11-02 22:56 ` Jiri Olsa
2020-11-03 18:58 ` Andrii Nakryiko
2020-11-03 19:05 ` Jiri Olsa
2020-11-03 19:23 ` Andrii Nakryiko
2020-11-03 19:34 ` Jiri Olsa
2020-11-03 20:27 ` Yonghong Song
2020-11-03 23:18 ` Jiri Olsa
2020-11-03 18:55 ` Andrii Nakryiko
2020-11-03 23:22 ` Jiri Olsa
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