linux-kernel - Re: um: WARNING: vmlinux: 'memcpy' exported twice. Previous export was in vmlinux

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Date:	Sun, 08 Mar 2009 12:49:16 +0200
From:	Boaz Harrosh <bharrosh@...asas.com>
To:	Américo Wang <xiyou.wangcong@...il.com>
CC:	uml-devel <user-mode-linux-devel@...ts.sourceforge.net>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: um: WARNING: vmlinux: 'memcpy' exported twice. Previous export
 was in vmlinux

Américo Wang wrote:
> On Thu, Mar 05, 2009 at 07:27:31PM +0200, Boaz Harrosh wrote:
>> Américo Wang wrote:
>>> On Thu, Mar 05, 2009 at 03:45:36PM +0200, Boaz Harrosh wrote:
>>>> Américo Wang wrote:
>>>>> On Thu, Mar 05, 2009 at 02:13:58PM +0200, Boaz Harrosh wrote:
>>>>>> On today's linus v2.6.29-rc7-3-g559595a
>>>>>>
>>>>>> Doing make ARCH=um defconfig & make ARCH=um
>>>>>> give's me:
>>>>>>
>>>>>> LD vmlinux.o
>>>>>> MODPOST vmlinux.o
>>>>>> WARNING: vmlinux: 'memcpy' exported twice. Previous export was in vmlinux
>>>>>>
>>>>>>
>>>>>> Sorry if this is a duplicate report
>>>>>>
>>>>> Weird...
>>>>> I tried to compile like what you said, I can't reproduce it.
>>>>>
>>>>> Which gcc are you using?
>>>>>
>>>>> Thanks.
>>>>>
>>>> $ gcc --version
>>>> gcc (GCC) 4.3.2 20081105 (Red Hat 4.3.2-7)
>>>>
>>>> I'm running on an x86_64 Fedora10 system (updated recently)
>>>> $ uname -o -s -r -m -p -i
>>>> Linux 2.6.27.15-170.2.24.fc10.x86_64 x86_64 x86_64 x86_64 GNU/Linux
>>>>
>>> I am using the same thing, but on i386. I still can't reproduce it. :(
>>>
>> What can I say I just did it again from scratch
>>
>> $ mkdir .build_um
>> $ make ARCH=um KBUILD_OUTPUT=.build_um defconfig
>> $ make ARCH=um KBUILD_OUTPUT=.build_um
>>
>> (I'm using KBUILD_OUTPUT= because O= does not work when also using M= with
>> external modules, so it's a habit)
>>
>> Thanks for your help. I will try to bisect it on Sunday
> 
> Hi, Boaz.
> 
> I am sorry that I don't have an x86_64 machine to use, but I know
> why this happens now. :)
> 
> Would you like to try the following patch? Thanks!
> 
> -------------->
> 
> Signed-off-by: WANG Cong <xiyou.wangcong@...il.com>
> 

Tested-by: Boaz Harrosh <bharrosh@...asas.com>

> ---
> diff --git a/arch/um/os-Linux/user_syms.c b/arch/um/os-Linux/user_syms.c
> index 74f49bb..89b48a1 100644
> --- a/arch/um/os-Linux/user_syms.c
> +++ b/arch/um/os-Linux/user_syms.c
> @@ -14,7 +14,6 @@
>  #undef memset
>  
>  extern size_t strlen(const char *);
> -extern void *memcpy(void *, const void *, size_t);
>  extern void *memmove(void *, const void *, size_t);
>  extern void *memset(void *, int, size_t);
>  extern int printf(const char *, ...);
> @@ -24,7 +23,11 @@ extern int printf(const char *, ...);
>  EXPORT_SYMBOL(strstr);
>  #endif
>  
> +#ifndef __x86_64__
> +extern void *memcpy(void *, const void *, size_t);
>  EXPORT_SYMBOL(memcpy);
> +#endif
> +
>  EXPORT_SYMBOL(memmove);
>  EXPORT_SYMBOL(memset);
>  EXPORT_SYMBOL(printf);
>  

Yes this works. But it is weird, what is the difference between
__x86_64__ and any other platform?

Thanks
Boaz
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