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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Peter Collingbourne <pcc@google.com>,
	James Morse <james.morse@arm.com>, Borislav Petkov <bp@suse.de>,
	Ingo Molnar <mingo@redhat.com>,
	Russell King <linux@armlinux.org.uk>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Arvind Sankar <nivedita@alum.mit.edu>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	Linux-Arch <linux-arch@vger.kernel.org>,
	linux-efi <linux-efi@vger.kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH v6 13/29] arm64/build: Assert for unwanted sections
Date: Mon, 26 Oct 2020 17:01:24 +0100
Message-ID: <CAMuHMdUJFEt3LxWHk73AsLDGhjzBvJGAML76UAxeGzb4zOf96w@mail.gmail.com> (raw)
In-Reply-To: <CAMuHMdUw9KwC=EVB60yjg7mA7Fg-efOiKE7577p+uEdGJVS2OQ@mail.gmail.com>

On Mon, Oct 26, 2020 at 2:29 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Mon, Oct 26, 2020 at 1:29 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Fri, Aug 21, 2020 at 9:56 PM Kees Cook <keescook@chromium.org> wrote:
> > > In preparation for warning on orphan sections, discard
> > > unwanted non-zero-sized generated sections, and enforce other
> > > expected-to-be-zero-sized sections (since discarding them might hide
> > > problems with them suddenly gaining unexpected entries).
> > >
> > > Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> > > Signed-off-by: Kees Cook <keescook@chromium.org>
> >
> > This is now commit be2881824ae9eb92 ("arm64/build: Assert for unwanted
> > sections") in v5.10-rc1, and is causing the following error with
> > renesas_defconfig[1]:
> >
> >     aarch64-linux-gnu-ld: warning: orphan section `.eh_frame' from
> > `kernel/bpf/core.o' being placed in section `.eh_frame'
> >     aarch64-linux-gnu-ld: Unexpected GOT/PLT entries detected!
> >     aarch64-linux-gnu-ld: Unexpected run-time procedure linkages detected!
> >
> > I cannot reproduce this with the standard arm64 defconfig.
> >
> > I bisected the error to the aforementioned commit, but understand this
> > is not the real reason.  If I revert this commit, I still get:
> >
> >     aarch64-linux-gnu-ld: warning: orphan section `.got.plt' from
> > `arch/arm64/kernel/head.o' being placed in section `.got.plt'
> >     aarch64-linux-gnu-ld: warning: orphan section `.plt' from
> > `arch/arm64/kernel/head.o' being placed in section `.plt'
> >     aarch64-linux-gnu-ld: warning: orphan section `.data.rel.ro' from
> > `arch/arm64/kernel/head.o' being placed in section `.data.rel.ro'
> >     aarch64-linux-gnu-ld: warning: orphan section `.eh_frame' from
> > `kernel/bpf/core.o' being placed in section `.eh_frame'
> >
> > I.e. including the ".eh_frame" warning. I have tried bisecting that
> > warning (i.e. with be2881824ae9eb92 reverted), but that leads me to
> > commit b3e5d80d0c48c0cc ("arm64/build: Warn on orphan section
> > placement"), which is another red herring.
>
> kernel/bpf/core.o is the only file containing an eh_frame section,
> causing the warning.
> If I compile core.c with "-g" added, like arm64 defconfig does, the
> eh_frame section is no longer emitted.
>
> Hence setting CONFIG_DEBUG_INFO=y, cfr. arm64 defconfig, the warning
> is gone, but I'm back to the the "Unexpected GOT/PLT entries" below...
>
> > Note that even on plain be2881824ae9eb92, I get:
> >
> >     aarch64-linux-gnu-ld: Unexpected GOT/PLT entries detected!
> >     aarch64-linux-gnu-ld: Unexpected run-time procedure linkages detected!
> >
> > The parent commit obviously doesn't show that (but probably still has
> > the problem).

Reverting both
b3e5d80d0c48c0cc ("arm64/build: Warn on orphan section placement")
be2881824ae9eb92 ("arm64/build: Assert for unwanted sections")
seems to solve my problems, without any ill effects?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

  reply index

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-21 19:42 [PATCH v6 00/29] Warn on orphan section placement Kees Cook
2020-08-21 19:42 ` [PATCH v6 01/29] vmlinux.lds.h: Create COMMON_DISCARDS Kees Cook
2020-09-01 11:48   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 02/29] vmlinux.lds.h: Add .gnu.version* to COMMON_DISCARDS Kees Cook
2020-09-01 11:48   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 03/29] vmlinux.lds.h: Avoid KASAN and KCSAN's unwanted sections Kees Cook
2020-09-01 11:48   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 04/29] vmlinux.lds.h: Split ELF_DETAILS from STABS_DEBUG Kees Cook
2020-09-01 11:48   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 05/29] vmlinux.lds.h: Add .symtab, .strtab, and .shstrtab to ELF_DETAILS Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 06/29] vmlinux.lds.h: add PGO and AutoFDO input sections Kees Cook
2020-09-01 11:47   ` [tip: core/build] vmlinux.lds.h: Add " tip-bot2 for Nick Desaulniers
2020-08-21 19:42 ` [PATCH v6 07/29] efi/libstub: Disable -mbranch-protection Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 08/29] arm64/mm: Remove needless section quotes Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 09/29] arm64/kernel: Remove needless Call Frame Information annotations Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 10/29] arm64/build: Remove .eh_frame* sections due to unwind tables Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 11/29] arm64/build: Use common DISCARDS in linker script Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 12/29] arm64/build: Add missing DWARF sections Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 13/29] arm64/build: Assert for unwanted sections Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-10-26 12:29   ` [PATCH v6 13/29] " Geert Uytterhoeven
2020-10-26 13:29     ` Geert Uytterhoeven
2020-10-26 16:01       ` Geert Uytterhoeven [this message]
2020-10-26 17:38         ` Ard Biesheuvel
2020-10-26 17:43           ` Geert Uytterhoeven
2020-10-26 17:48             ` Nick Desaulniers
2020-10-26 17:53               ` Geert Uytterhoeven
2020-10-27  8:37                 ` Geert Uytterhoeven
2020-10-27 19:25               ` Geert Uytterhoeven
2020-10-27 19:33                 ` Ard Biesheuvel
2020-10-27 20:00                   ` Arvind Sankar
2020-10-27 20:12                 ` Nick Desaulniers
2020-10-27 20:15                   ` Ard Biesheuvel
2020-10-27 20:17                     ` Nick Desaulniers
2020-10-27 20:30                       ` Arvind Sankar
2020-10-27 20:40                         ` Nick Desaulniers
2020-10-27 21:24                           ` Arvind Sankar
2020-10-27 20:28                     ` Nick Desaulniers
2020-10-27 20:32                       ` Arvind Sankar
2020-10-27 20:36                         ` Nick Desaulniers
2020-10-28 21:36                     ` Alexei Starovoitov
2020-10-27  8:51             ` Geert Uytterhoeven
2020-10-27 10:08           ` Jean-Philippe Brucker
2020-10-27 10:20             ` Geert Uytterhoeven
2020-10-27 11:29               ` Ard Biesheuvel
2020-10-27 11:53                 ` Naresh Kamboju
2020-10-27 13:56                 ` Ard Biesheuvel
2020-08-21 19:42 ` [PATCH v6 14/29] arm64/build: Warn on orphan section placement Kees Cook
2020-08-21 19:42 ` [PATCH v6 15/29] arm/build: Refactor linker script headers Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 16/29] arm/build: Explicitly keep .ARM.attributes sections Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 17/29] arm/build: Add missing sections Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:42 ` [PATCH v6 18/29] arm/build: Assert for unwanted sections Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:43 ` [PATCH v6 19/29] arm/build: Warn on orphan section placement Kees Cook
2020-08-21 19:43 ` [PATCH v6 20/29] arm/boot: Handle all sections explicitly Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:43 ` [PATCH v6 21/29] arm/boot: Warn on orphan section placement Kees Cook
2020-08-21 19:43 ` [PATCH v6 22/29] x86/asm: Avoid generating unused kprobe sections Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:43 ` [PATCH v6 23/29] x86/build: Enforce an empty .got.plt section Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:43 ` [PATCH v6 24/29] x86/build: Assert for unwanted sections Kees Cook
2020-09-01 11:47   ` [tip: core/build] x86/build: Add asserts " tip-bot2 for Kees Cook
2020-08-21 19:43 ` [PATCH v6 25/29] x86/build: Warn on orphan section placement Kees Cook
2020-08-21 19:43 ` [PATCH v6 26/29] x86/boot/compressed: Reorganize zero-size section asserts Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:43 ` [PATCH v6 27/29] x86/boot/compressed: Remove, discard, or assert for unwanted sections Kees Cook
2020-08-21 20:01   ` Arvind Sankar
2020-08-21 21:21     ` Kees Cook
2020-08-21 21:28       ` Arvind Sankar
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:43 ` [PATCH v6 28/29] x86/boot/compressed: Add missing debugging sections to output Kees Cook
2020-09-01 11:47   ` [tip: core/build] " tip-bot2 for Kees Cook
2020-08-21 19:43 ` [PATCH v6 29/29] x86/boot/compressed: Warn on orphan section placement Kees Cook
2020-08-31 19:41 ` [PATCH v6 00/29] " Kees Cook
2020-09-01  7:11   ` Ingo Molnar
2020-09-01  7:59     ` Ingo Molnar
2020-09-01  8:16       ` Ingo Molnar
2020-09-01 15:17         ` Kees Cook
2020-09-01 18:02           ` Nick Desaulniers
2020-09-01 23:18             ` Kees Cook
2020-09-01 23:54               ` Nick Desaulniers

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