diff mbox series

[2/2] modpost: Add '.ltext' and '.ltext.*' to TEXT_SECTIONS

Message ID 20240123-fix-uml-clang-18-v1-2-efc095519cf9@kernel.org
State Handled Elsewhere
Headers show
Series Fix UML build with clang-18 and newer | expand

Commit Message

Nathan Chancellor Jan. 23, 2024, 10:59 p.m. UTC
After the linked LLVM change, building ARCH=um defconfig results in a
segmentation fault in modpost. 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(-)

Comments

Masahiro Yamada Jan. 27, 2024, 3:49 p.m. UTC | #1
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
>
diff mbox series

Patch

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"