Re: [PATCH] init.h: discard exitcall symbols early

[Petr Mladek <pmladek@suse.com>]

Adding module loader maintainers into Cc to make them aware of this
change.

On Tue 2026-03-31 16:28:38, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> Any __exitcall() and built-in module_exit() handler is marked as __used,
> which leads to the code being included in the object file and later
> discarded at link time.

Is this safe for dynamically loaded modules?

Honestly, I am not sure what is the exact efect of this change.
The dynamically loadded modules just came to my mind...

Best Regards,
Petr

> As far as I can tell, this was originally added at the same time
> as initcalls were marked the same way, to prevent them from getting
> dropped with gcc-3.4, but it was never actaully necessary to keep exit
> functions around.
> 
> Mark them as __maybe_unused instead, which lets the compiler treat
> the exitcalls as entirely unused, and make better decisions about
> dropping specializing static functions called from these.
> 
> Link: https://lore.kernel.org/all/acruxMNdnUlyRHiy@google.com/
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  include/linux/init.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/init.h b/include/linux/init.h
> index 5db55c660124..ad5c19763034 100644
> --- a/include/linux/init.h
> +++ b/include/linux/init.h
> @@ -47,7 +47,7 @@
>  #define __initdata	__section(".init.data")
>  #define __initconst	__section(".init.rodata")
>  #define __exitdata	__section(".exit.data")
> -#define __exit_call	__used __section(".exitcall.exit")
> +#define __exit_call	__maybe_unused __section(".exitcall.exit")
>  
>  /*
>   * modpost check for section mismatches during the kernel build.
> -- 
> 2.39.5