Unknown Symbol fc20

[Josh Boyer]

On Wed, Jul 10, 2013 at 10:17:22AM -0400, Dave Anderson wrote:
> 
> 
> > > while yum updating
> > > 
> > > Installing :
> > > kernel-3.11.0-0.rc0.git2.1.fc20.x86_64
> > > 1/1 depmod:
> > > WARNING: /lib/modules/3.11.0-0.rc0.git2.1.fc20.x86_64/kernel/drivers/char/crash.ko
> > > needs unknown symbol page_is_ram Verifying  :
> > > kernel-3.11.0-0.rc0.git2.1.fc20.x86_64                                                                       
> > Thanks.  Someone else reported this yesterday as well.  It shouldn't
> > cause any problems for most Fedora users, as it will only impact those
> > using the crash tool.
> > 
> > josh
> 
> OK, but for those of us who use it, the change that presumably causes this 
> would be this part of this commit:
> 
> commit c5a130325f13b219438cb100e2da71a3e31199f3
> Author: Chen Gong <gong.chen at linux.intel.com>
> Date:   Thu Jun 6 15:20:51 2013 -0700
> 
>     ACPI/APEI: Add parameter check before error injection
>     
>     When param1 is enabled in EINJ but not assigned with a valid
>     value, sometimes it will cause the error like below:
>     
>     APEI: Can not request [mem 0x7aaa7000-0x7aaa7007] for APEI EINJ Trigger registers
>     
>     It is because some firmware will access target address specified in
>     param1 to trigger the error when injecting memory error. This will
>     cause resource conflict with regular memory. So It must be removed
>     from trigger table resources, but incorrect param1/param2
>     combination will stop this action. Add extra check to avoid
>     this kind of error.
>     
>     Signed-off-by: Chen Gong <gong.chen at linux.intel.com>
>     Signed-off-by: Tony Luck <tony.luck at intel.com>
> 
> diff --git a/kernel/resource.c b/kernel/resource.c
> index d738698..77bf11a 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -409,6 +409,7 @@ int __weak page_is_ram(unsigned long pfn)
>  {
>         return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
>  }
> +EXPORT_SYMBOL_GPL(page_is_ram);
>  
>  void __weak arch_remove_reservations(struct resource *avail)
>  {
> 
> 
> where the additional EXPORT_SYMBOL_GPL(page_is_ram) above now makes
> it available from both kernel/resource.c and arch/x86/mm/ioremap.c.  
> Why would that make it an unknown symbol? 

I don't see it in arch/x86/mm/ioremap.c at all.  It's defined as __weak
in kernel/resource.c, so I'm guessing some kind of interaction there is
going wrong with the linking?

josh