From: Sami Tolvanen <samitolvanen@google.com>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: X86 ML <x86@kernel.org>, Kees Cook <keescook@chromium.org>,
Peter Zijlstra <peterz@infradead.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Sedat Dilek <sedat.dilek@gmail.com>,
linux-hardening@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH 01/15] objtool: Find a destination for jumps beyond the section end
Date: Tue, 20 Apr 2021 13:25:43 -0700 [thread overview]
Message-ID: <CABCJKudO9Ovuih3ieQ70w8y744Cg3tPnciVBhCuuBPuhq4i3Xg@mail.gmail.com> (raw)
In-Reply-To: <20210420181412.3g5dsyhggxnvif7k@treble>
On Tue, Apr 20, 2021 at 11:14 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>
> On Fri, Apr 16, 2021 at 01:38:30PM -0700, Sami Tolvanen wrote:
> > With -ffunction-sections, Clang can generate a jump beyond the end of
> > a section when the section ends in an unreachable instruction.
>
> Why? Can you show an example?
Here's the warning I'm seeing when building allyesconfig + CFI:
vmlinux.o: warning: objtool:
rockchip_spi_transfer_one.f088382d97b74759d70e27e891fe8f1c()+0x149:
can't find jump dest instruction at
.text.rockchip_spi_transfer_one.f088382d97b74759d70e27e891fe8f1c+0x7dc
$ objdump -d -r -j
.text.rockchip_spi_transfer_one.f088382d97b74759d70e27e891fe8f1c
vmlinux.o
0000000000000000 <rockchip_spi_transfer_one.f088382d97b74759d70e27e891fe8f1c>:
...
149: 0f 85 8d 06 00 00 jne 7dc <.compoundliteral.4>
...
7d7: e8 00 00 00 00 callq 7dc <.compoundliteral.4>
7d8: R_X86_64_PLT32 __stack_chk_fail-0x4
Sami
next prev parent reply other threads:[~2021-04-20 20:26 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-16 20:38 [PATCH 00/15] x86: Add support for Clang CFI Sami Tolvanen
2021-04-16 20:38 ` [PATCH 01/15] objtool: Find a destination for jumps beyond the section end Sami Tolvanen
2021-04-20 18:14 ` Josh Poimboeuf
2021-04-20 20:25 ` Sami Tolvanen [this message]
2021-04-20 22:55 ` Josh Poimboeuf
2021-04-20 22:58 ` Nick Desaulniers
2021-04-16 20:38 ` [PATCH 02/15] objtool: Add CONFIG_CFI_CLANG support Sami Tolvanen
2021-04-20 19:47 ` Josh Poimboeuf
2021-04-20 20:45 ` Sami Tolvanen
2021-04-16 20:38 ` [PATCH 03/15] objtool: Add ASM_STACK_FRAME_NON_STANDARD Sami Tolvanen
2021-04-16 20:38 ` [PATCH 04/15] static_call: Use global functions for the self-test Sami Tolvanen
2021-04-16 21:37 ` Thomas Gleixner
2021-04-17 0:16 ` Thomas Gleixner
2021-04-16 20:38 ` [PATCH 05/15] x86: Implement function_nocfi Sami Tolvanen
2021-04-16 21:18 ` Borislav Petkov
2021-04-16 21:49 ` Sami Tolvanen
2021-04-16 22:02 ` Borislav Petkov
2021-04-16 22:06 ` Andy Lutomirski
2021-04-16 22:14 ` Borislav Petkov
2021-04-16 22:20 ` Andy Lutomirski
2021-04-16 22:37 ` Kees Cook
2021-04-16 23:02 ` Thomas Gleixner
2021-04-17 10:16 ` Thomas Gleixner
2021-04-19 15:13 ` Sami Tolvanen
2021-04-16 22:28 ` Kees Cook
2021-04-16 22:52 ` Andy Lutomirski
2021-04-16 22:58 ` Kees Cook
2021-04-16 23:40 ` Kees Cook
2021-04-17 23:19 ` Andy Lutomirski
2021-04-17 23:53 ` Thomas Gleixner
2021-04-18 0:11 ` Andy Lutomirski
2021-04-18 16:17 ` Thomas Gleixner
2021-04-18 22:57 ` Andy Lutomirski
2021-04-19 15:20 ` Sami Tolvanen
2021-04-19 15:26 ` David Laight
2021-04-19 17:46 ` Andy Lutomirski
2021-04-17 14:20 ` David Laight
2021-04-17 15:48 ` Andy Lutomirski
2021-04-19 8:40 ` Rasmus Villemoes
2021-04-19 16:45 ` Joao Moreira
2021-04-19 21:52 ` David Laight
2021-04-16 22:16 ` Kees Cook
2021-04-16 22:13 ` Thomas Gleixner
2021-04-16 20:38 ` [PATCH 06/15] x86: Avoid CFI jump tables in IDT and entry points Sami Tolvanen
2021-04-16 22:26 ` Thomas Gleixner
2021-04-16 23:56 ` Kees Cook
2021-04-17 0:02 ` Thomas Gleixner
2021-04-16 20:38 ` [PATCH 07/15] x86/ftrace: Use function_nocfi in MCOUNT_ADDR Sami Tolvanen
2021-04-16 20:38 ` [PATCH 08/15] x86/extable: Do not mark exception callback as CFI Sami Tolvanen
2021-04-16 20:38 ` [PATCH 09/15] x86/alternatives: Use C int3 selftest but disable KASAN Sami Tolvanen
2021-04-17 11:37 ` Peter Zijlstra
2021-04-19 15:26 ` Sami Tolvanen
2021-04-20 7:19 ` Peter Zijlstra
2021-04-16 20:38 ` [PATCH 10/15] x86/purgatory: Disable CFI Sami Tolvanen
2021-04-16 20:38 ` [PATCH 11/15] x86, relocs: Ignore __typeid__ relocations Sami Tolvanen
2021-04-16 20:38 ` [PATCH 12/15] x86, module: " Sami Tolvanen
2021-04-16 20:38 ` [PATCH 13/15] x86, cpu: Use LTO for cpu.c with CFI Sami Tolvanen
2021-04-16 20:38 ` [PATCH 14/15] x86, kprobes: Fix optprobe_template_func type mismatch Sami Tolvanen
2021-04-16 20:38 ` [PATCH 15/15] x86, build: Allow CONFIG_CFI_CLANG to be selected Sami Tolvanen
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