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From: Masahiro Yamada <masahiroy@kernel.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: richard@nod.at, anton.ivanov@cambridgegreys.com,
	johannes@sipsolutions.net,  nicolas@fjasle.eu,
	ndesaulniers@google.com, morbo@google.com,
	 justinstitt@google.com, linux-um@lists.infradead.org,
	 linux-kbuild@vger.kernel.org, llvm@lists.linux.dev,
	patches@lists.linux.dev,  stable@vger.kernel.org
Subject: Re: [PATCH 2/2] modpost: Add '.ltext' and '.ltext.*' to TEXT_SECTIONS
Date: Sun, 28 Jan 2024 00:49:25 +0900	[thread overview]
Message-ID: <CAK7LNASWAXwcHtzsW1vex6kuL7Jf+M2HiBhTGhHYfKnAoMqvPA@mail.gmail.com> (raw)
In-Reply-To: <20240123-fix-uml-clang-18-v1-2-efc095519cf9@kernel.org>

On Wed, Jan 24, 2024 at 8:00 AM Nathan Chancellor <nathan@kernel.org> wrote:
>
> After the linked LLVM change, building ARCH=um defconfig results in a
> segmentation fault in modpost.

Yeah, this is a mistake in my commits.
The NULL pointer access should be fixed, but that is a separate issue.

Anyway, I applied this patch.



> Prior to commit a23e7584ecf3 ("modpost:
> unify 'sym' and 'to' in default_mismatch_handler()"), there was a
> warning:
>
>   WARNING: modpost: vmlinux.o(__ex_table+0x88): Section mismatch in reference to the .ltext:(unknown)
>   WARNING: modpost: The relocation at __ex_table+0x88 references
>   section ".ltext" which is not in the list of
>   authorized sections.  If you're adding a new section
>   and/or if this reference is valid, add ".ltext" to the
>   list of authorized sections to jump to on fault.
>   This can be achieved by adding ".ltext" to
>   OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.
>
> The linked LLVM change moves global objects to the '.ltext' (and
> '.ltext.*' with '-ffunction-sections') sections with '-mcmodel=large',
> which ARCH=um uses. These sections should be handled just as '.text'
> and '.text.*' are, so add them to TEXT_SECTIONS.
>
> Cc: stable@vger.kernel.org
> Closes: https://github.com/ClangBuiltLinux/linux/issues/1981
> Link: https://github.com/llvm/llvm-project/commit/4bf8a688956a759b7b6b8d94f42d25c13c7af130
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>  scripts/mod/modpost.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index cb6406f485a9..f7c4d3fe4381 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -807,7 +807,8 @@ static void check_section(const char *modname, struct elf_info *elf,
>
>  #define DATA_SECTIONS ".data", ".data.rel"
>  #define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \
> -               ".kprobes.text", ".cpuidle.text", ".noinstr.text"
> +               ".kprobes.text", ".cpuidle.text", ".noinstr.text", \
> +               ".ltext", ".ltext.*"
>  #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
>                 ".fixup", ".entry.text", ".exception.text", \
>                 ".coldtext", ".softirqentry.text"
>
> --
> 2.43.0
>


-- 
Best Regards
Masahiro Yamada


  reply	other threads:[~2024-01-27 15:50 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-23 22:59 [PATCH 0/2] Fix UML build with clang-18 and newer Nathan Chancellor
2024-01-23 22:59 ` [PATCH 1/2] um: Fix adding '-no-pie' for clang Nathan Chancellor
2024-01-27 15:46   ` Masahiro Yamada
2024-01-23 22:59 ` [PATCH 2/2] modpost: Add '.ltext' and '.ltext.*' to TEXT_SECTIONS Nathan Chancellor
2024-01-27 15:49   ` Masahiro Yamada [this message]
2024-01-27 15:43 ` [PATCH 0/2] Fix UML build with clang-18 and newer Masahiro Yamada

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