Re: [PATCH v5 0/3] Kbuild: DWARF v5 support

From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andrii@kernel.org>,
	Jiri Olsa <jolsa@kernel.org>, Sedat Dilek <sedat.dilek@gmail.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Clang-Built-Linux ML <clang-built-linux@googlegroups.com>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	linux-arch <linux-arch@vger.kernel.org>,
	Jakub Jelinek <jakub@redhat.com>,
	Fangrui Song <maskray@google.com>,
	Caroline Tice <cmtice@google.com>,
	Nick Clifton <nickc@redhat.com>,
	dwarves@vger.kernel.org, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH v5 0/3] Kbuild: DWARF v5 support
Date: Wed, 3 Feb 2021 18:57:55 -0800	[thread overview]
Message-ID: <CAEf4Bzbn1app3LZ1oah5ARn81j5RMNxRRHPVAkeY3h_0q7+7fg@mail.gmail.com> (raw)
In-Reply-To: <CAKwvOdmniAMZD0LiFdr5N8eOwHqNFED2Pd=pwOFF2Y8eSRXUHA@mail.gmail.com>

On Wed, Feb 3, 2021 at 5:31 PM Nick Desaulniers <ndesaulniers@google.com> wrote:
>
> On Sun, Jan 17, 2021 at 12:14 PM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
> >
> > Em Fri, Jan 15, 2021 at 03:43:06PM -0800, Yonghong Song escreveu:
> > >
> > >
> > > On 1/15/21 3:34 PM, Nick Desaulniers wrote:
> > > > On Fri, Jan 15, 2021 at 3:24 PM Yonghong Song <yhs@fb.com> wrote:
> > > > >
> > > > >
> > > > >
> > > > > On 1/15/21 1:53 PM, Sedat Dilek wrote:
> > > > > > En plus, I encountered breakage with GCC v10.2.1 and LLVM=1 and
> > > > > > CONFIG_DEBUG_INFO_DWARF4.
> > > > > > So might be good to add a "depends on !DEBUG_INFO_BTF" in this combination.
> > > >
> > > > Can you privately send me your configs that repro? Maybe I can isolate
> > > > it to a set of configs?
> > > >
> > > > >
> > > > > I suggested not to add !DEBUG_INFO_BTF to CONFIG_DEBUG_INFO_DWARF4.
> > > > > It is not there before and adding this may suddenly break some users.
> > > > >
> > > > > If certain combination of gcc/llvm does not work for
> > > > > CONFIG_DEBUG_INFO_DWARF4 with pahole, this is a bug bpf community
> > > > > should fix.
> > > >
> > > > Is there a place I should report bugs?
> > >
> > > You can send bug report to Arnaldo Carvalho de Melo <acme@kernel.org>,
> > > dwarves@vger.kernel.org and bpf@vger.kernel.org.
> >
> > I'm coming back from vacation, will try to read the messages and see if
> > I can fix this.
>
> IDK about DWARF v4; that seems to work for me.  I was previously observing
> https://bugzilla.redhat.com/show_bug.cgi?id=1922698
> with DWARF v5.  I just re-pulled the latest pahole, rebuilt, and no
> longer see that warning.
>
> I now observe a different set.  I plan on attending "BPF office hours
> tomorrow morning," but if anyone wants a sneak peak of the errors and
> how to reproduce:
> https://gist.github.com/nickdesaulniers/ae8c9efbe4da69b1cf0dce138c1d2781
>

Is there another (easy) way to get your patch set without the b4 tool?
Is your patch set present in some patchworks instance, so that I can
download it in mbox format, for example?

>
> (FWIW: some other folks are hitting issues now with kernel's lack of
> DWARF v5 support: https://bugzilla.redhat.com/show_bug.cgi?id=1922707)
> --
> Thanks,
> ~Nick Desaulniers