Re: [PATCH] modules: Fix build error in moduleloader.h
From: Masami Hiramatsu
Date: Mon Jul 07 2014 - 22:51:40 EST
(2014/07/08 8:40), Rusty Russell wrote:
> Steven Rostedt <rostedt@xxxxxxxxxxx> writes:
>> 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:
>
> First, we have module_name() for exactly this.
>
> Second, there are two places like this: you hit
> CONFIG_MODULES_USE_ELF_REL and not CONFIG_MODULES_USE_ELF_RELA.
>
> (We could uninline them, and put them in module.c, but I think having
> them in the header is nice and self-documenting.)
>
> So does this work for you?
>
> Thanks,
> Rusty.
> PS. Masami Hiramatsu, your review should have caught the second case,
> at least :(
Oops, sorry, I missed the second one ... and this version seems good to me.
Thank you,
>
> Subject: modules: Fix build error in moduleloader.h
>
> 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);
> ^
> Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
> Based-on-the-true-story-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
>
> diff --git a/include/linux/moduleloader.h b/include/linux/moduleloader.h
> index 560ca53a75fa..7eeb9bbfb816 100644
> --- a/include/linux/moduleloader.h
> +++ b/include/linux/moduleloader.h
> @@ -45,7 +45,8 @@ static inline int apply_relocate(Elf_Shdr *sechdrs,
> unsigned int relsec,
> struct module *me)
> {
> - printk(KERN_ERR "module %s: REL relocation unsupported\n", me->name);
> + printk(KERN_ERR "module %s: REL relocation unsupported\n",
> + module_name(me));
> return -ENOEXEC;
> }
> #endif
> @@ -67,7 +68,8 @@ static inline int apply_relocate_add(Elf_Shdr *sechdrs,
> unsigned int relsec,
> struct module *me)
> {
> - printk(KERN_ERR "module %s: REL relocation unsupported\n", me->name);
> + printk(KERN_ERR "module %s: REL relocation unsupported\n",
> + module_name(me));
> return -ENOEXEC;
> }
> #endif
>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
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