All of lore.kernel.org
 help / color / mirror / Atom feed
From: Nathan Chancellor <nathan@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>, Kees Cook <keescook@chromium.org>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
	kernel test robot <lkp@intel.com>,
	Fangrui Song <maskray@google.com>
Subject: Re: [PATCH v3] vmlinux.lds.h: Define SANTIZER_DISCARDS with CONFIG_GCOV_KERNEL=y
Date: Thu, 25 Feb 2021 12:28:21 -0700	[thread overview]
Message-ID: <20210225192821.GA1975@MSI.localdomain> (raw)
In-Reply-To: <20210130004650.2682422-1-nathan@kernel.org>

On Fri, Jan 29, 2021 at 05:46:51PM -0700, Nathan Chancellor wrote:
> clang produces .eh_frame sections when CONFIG_GCOV_KERNEL is enabled,
> even when -fno-asynchronous-unwind-tables is in KBUILD_CFLAGS:
> 
> $ make CC=clang vmlinux
> ...
> ld: warning: orphan section `.eh_frame' from `init/main.o' being placed in section `.eh_frame'
> ld: warning: orphan section `.eh_frame' from `init/version.o' being placed in section `.eh_frame'
> ld: warning: orphan section `.eh_frame' from `init/do_mounts.o' being placed in section `.eh_frame'
> ld: warning: orphan section `.eh_frame' from `init/do_mounts_initrd.o' being placed in section `.eh_frame'
> ld: warning: orphan section `.eh_frame' from `init/initramfs.o' being placed in section `.eh_frame'
> ld: warning: orphan section `.eh_frame' from `init/calibrate.o' being placed in section `.eh_frame'
> ld: warning: orphan section `.eh_frame' from `init/init_task.o' being placed in section `.eh_frame'
> ...
> 
> $ rg "GCOV_KERNEL|GCOV_PROFILE_ALL" .config
> CONFIG_GCOV_KERNEL=y
> CONFIG_ARCH_HAS_GCOV_PROFILE_ALL=y
> CONFIG_GCOV_PROFILE_ALL=y
> 
> This was already handled for a couple of other options in
> commit d812db78288d ("vmlinux.lds.h: Avoid KASAN and KCSAN's unwanted
> sections") and there is an open LLVM bug for this issue. Take advantage
> of that section for this config as well so that there are no more orphan
> warnings.
> 
> Link: https://bugs.llvm.org/show_bug.cgi?id=46478
> Link: https://github.com/ClangBuiltLinux/linux/issues/1069
> Reported-by: kernel test robot <lkp@intel.com>
> Reviewed-by: Fangrui Song <maskray@google.com>
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
> 
> v2 -> v3:
> 
> * Fix double "unwanted" in comment section per Sedat.
> 
> v1 -> v2:
> 
> * Keep configs and flag names alphabetized.
> 
> * Drop mention of -ftest-coverage since it does not cause this issue per
>   Fangrui.
> 
> * Pick up review tags from Fangrui and Nick.
> 
>  include/asm-generic/vmlinux.lds.h | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index b2b3d81b1535..b61b537177fb 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -988,12 +988,13 @@
>  #endif
>  
>  /*
> - * Clang's -fsanitize=kernel-address and -fsanitize=thread produce
> - * unwanted sections (.eh_frame and .init_array.*), but
> - * CONFIG_CONSTRUCTORS wants to keep any .init_array.* sections.
> + * Clang's -fprofile-arcs, -fsanitize=kernel-address, and
> + * -fsanitize=thread produce unwanted sections (.eh_frame
> + * and .init_array.*), but CONFIG_CONSTRUCTORS wants to
> + * keep any .init_array.* sections.
>   * https://bugs.llvm.org/show_bug.cgi?id=46478
>   */
> -#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KCSAN)
> +#if defined(CONFIG_GCOV_KERNEL) || defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KCSAN)
>  # ifdef CONFIG_CONSTRUCTORS
>  #  define SANITIZER_DISCARDS						\
>  	*(.eh_frame)
> 
> base-commit: bec4c2968fce2f44ce62d05288a633cd99a722eb
> -- 
> 2.30.0
> 

Andrew, Arnd, or Kees:

Would one of you be able to pick this up and get it to Linus? I think
the 0day bot just tripped over this again:

https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org/message/BXBY7OPVMOCCUZSCFEZXI7RG65RJWJ52/
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org/message/QF62LWM6YSNWWNOM7AXYK4734AKH2SVT/

Cheers,
Nathan

  reply	other threads:[~2021-02-25 19:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-29 20:11 [PATCH] vmlinux.lds.h: Define SANTIZER_DISCARDS with CONFIG_GCOV_KERNEL=y Nathan Chancellor
2021-01-29 20:18 ` Nick Desaulniers
2021-01-29 21:27   ` Fangrui Song
2021-01-30  0:25 ` [PATCH v2] " Nathan Chancellor
2021-01-30  0:39   ` Sedat Dilek
2021-01-30  0:46   ` [PATCH v3] " Nathan Chancellor
2021-02-25 19:28     ` Nathan Chancellor [this message]
2021-02-25 21:19     ` Kees Cook

Reply instructions:

You may reply publicly 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=20210225192821.GA1975@MSI.localdomain \
    --to=nathan@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=arnd@arndb.de \
    --cc=clang-built-linux@googlegroups.com \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lkp@intel.com \
    --cc=maskray@google.com \
    --cc=ndesaulniers@google.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
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.