Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230615145607.3469985-1-revest@chromium.org> <CABRcYm+C+tPwXAGnaDRR_U2hzyt+09fjkKBp3tPx6iKT4wBE2Q@mail.gmail.com>
 <fbd79f5f2b250ec913c78d91b94ca96fb96f67ee.camel@gmail.com>
In-Reply-To: <fbd79f5f2b250ec913c78d91b94ca96fb96f67ee.camel@gmail.com>
From:   Florent Revest <revest@chromium.org>
Date:   Mon, 19 Jun 2023 13:20:20 +0200
Message-ID: <CABRcYmLaummOg=Nf0qXVN2eci=25OqXLD0zpCUz4CgmTjvo9LA@mail.gmail.com>
Subject: Re: [PATCH bpf] bpf/btf: Accept function names that contain dots
To:     Eduard Zingerman <eddyz87@gmail.com>
Cc:     bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev, martin.lau@linux.dev, ast@kernel.org,
        daniel@iogearbox.net, andrii@kernel.org, song@kernel.org,
        yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org,
        sdf@google.com, haoluo@google.com, jolsa@kernel.org,
        nathan@kernel.org, ndesaulniers@google.com, trix@redhat.com,
        stable@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Thu, Jun 15, 2023 at 7:05=E2=80=AFPM Eduard Zingerman <eddyz87@gmail.com=
> wrote:
>
> On Thu, 2023-06-15 at 17:44 +0200, Florent Revest wrote:
> > An easy reproducer is:
> >
> > $ touch pwet.c
> >
> > $ clang -g -fsanitize=3Dkernel-address -c -o pwet.o pwet.c
> > $ llvm-dwarfdump pwet.o | grep module_ctor
> >
> > $ clang -fno-integrated-as -g -fsanitize=3Dkernel-address -c -o pwet.o =
pwet.c
> > $ llvm-dwarfdump pwet.o | grep module_ctor
> >                 DW_AT_name      ("asan.module_ctor")
>
> Interestingly, I am unable to reproduce it using either
> clang version 14.0.0-1ubuntu1 or clang main (bd66f4b1da30).

Somehow, I didn't think of trying other clang versions! Thanks, that's
a good point Eduard. :)

I also can't reproduce it on a 14x build.

However, I seem to be able to reproduce it on main:

  git clone https://github.com/llvm/llvm-project.git
  mkdir llvm-project/build
  cd llvm-project/build
  git checkout bd66f4b1da30
  cmake -DLLVM_ENABLE_PROJECTS=3Dclang -DCMAKE_BUILD_TYPE=3DRelease -G
"Unix Makefiles" ../llvm
  make -j $(nproc)

  bin/clang -fno-integrated-as -g -fsanitize=3Dkernel-address -c -o
~/pwet.o ~/pwet.c
  bin/llvm-dwarfdump ~/pwet.o | grep module_ctor
  # Shows module_ctor

I started a bisection, hopefully that will point to something interesting