Re: [PATCH] modpost: Add .irqentry.text to OTHER_SECTIONS

[Masahiro Yamada]

On Sun, Dec 1, 2024 at 8:17 PM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> The compiler can fully inline the actual handler function of an interrupt
> entry into the .irqentry.text entry point. If such a function contains an
> access which has an exception table entry, modpost complains about a
> section mismatch:
>
>   WARNING: vmlinux.o(__ex_table+0x447c): Section mismatch in reference ...
>
>   The relocation at __ex_table+0x447c references section ".irqentry.text"
>   which is not in the list of authorized sections.
>
> Add .irqentry.text to OTHER_SECTIONS to cure the issue.
>
> Reported-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>

I found the context in LKML.


Closes: https://lore.kernel.org/all/20241128111844.GE10431@xxxxxxxxxx/



However, is this still relevant to the mainline kernel?

In Linux 5.4.y, I agree this because smp_apic_timer_interrupt()
is annotated as __irq_entry:

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/arch/x86/kernel/apic/apic.c?id=v5.4.286#n1145



In this mainline kernel, DEFINE_IDTENTRY_SYSVEC()
expands to a normal .text function which is explicitly
annotated 'noinline'.





> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
>  scripts/mod/modpost.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -785,7 +785,7 @@ static void check_section(const char *mo
>                 ".ltext", ".ltext.*"
>  #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
>                 ".fixup", ".entry.text", ".exception.text", \
> -               ".coldtext", ".softirqentry.text"
> +               ".coldtext", ".softirqentry.text", ".irqentry.text"
>
>  #define ALL_TEXT_SECTIONS  ".init.text", ".exit.text", \
>                 TEXT_SECTIONS, OTHER_TEXT_SECTIONS



--
Best Regards
Masahiro Yamada