Re: [PATCH] modules: Fix build error in moduleloader.h

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

(2014/07/03 22:21), Steven Rostedt wrote:
> Fengguang Wu's build bot detected that if moduleloader.h is included in
> a C file (used by ftrace and kprobes to access module_alloc() when
> available), that it can fail to build if CONFIG_MODULES and
> CONFIG_MODULES_USE_ELF_REL is not defined.
> 
> This is because there's a printk() that dereferences struct module to
> print the name of the module. But as struct module does not exist when
> CONFIG_MODULES is not defined we get this error:
> 
>    include/linux/moduleloader.h: In function 'apply_relocate':
>>> include/linux/moduleloader.h:48:63: error: dereferencing pointer to incomplete type  
>      printk(KERN_ERR "module %s: REL relocation unsupported\n", me->name);
>                                                                   ^
> Avoid the printk if CONFIG_MODULES is not set.

Looks OK to me. BTW, CONFIG_KPROBES depends on CONFIG_MODULES,
so currently kprobes itself doesn't hit that problem.

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thank you, :)

> 
> Reported-by: kbuild test robot <fengguang.wu@intel.com>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> diff --git a/include/linux/moduleloader.h b/include/linux/moduleloader.h
> index 560ca53..d9da807 100644
> --- a/include/linux/moduleloader.h
> +++ b/include/linux/moduleloader.h
> @@ -45,7 +45,10 @@ static inline int apply_relocate(Elf_Shdr *sechdrs,
>  				 unsigned int relsec,
>  				 struct module *me)
>  {
> +/* me->name only exists if modules are enabled */
> +#ifdef CONFIG_MODULES
>  	printk(KERN_ERR "module %s: REL relocation unsupported\n", me->name);
> +#endif
>  	return -ENOEXEC;
>  }
>  #endif
> 


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com