Re: kernel BUG at kernel/kallsyms.c:222!

From: Ming Lei
Date: Mon Nov 11 2013 - 02:54:02 EST


Hi,

On Mon, Nov 11, 2013 at 2:43 PM, Axel Lin <axel.lin@xxxxxxxxxx> wrote:
> 2013/11/11 Rusty Russell <rusty@xxxxxxxxxxxxxxx>:
>
> Hi Rusty,
>
> I don't have other noMMU platform to test.
> But I think this issue impacts various !CONFIG_MMU platforms:
> We have CONFIG_PAGE_OFFSET=0xC0000000 in various default configs.
> For !CONFIG_MMU case, it just don't use the CONFIG_PAGE_OFFSET setting.
> So use CONFIG_PAGE_OFFSET to filter symbols looks wrong to me for all
> !CONFIG_MMU cases.
>
> Below is PAGE_OFFSET setting for !CONFIG_MMU case:
> (arch/arm/include/asm/memory.h)
>
> #ifndef PHYS_OFFSET
> #define PHYS_OFFSET UL(CONFIG_DRAM_BASE)
> #endif
>
> #ifndef END_MEM
> #define END_MEM (UL(CONFIG_DRAM_BASE) + CONFIG_DRAM_SIZE)
> #endif
>
> #ifndef PAGE_OFFSET
> #define PAGE_OFFSET (PHYS_OFFSET)
> #endif
>
> My patchs for gpl327xx SoC is still in very early stage.
> I think you should send your fix upstream because I think it impacts other
> noMMU platforms (for above reason).

I suggest to do it when we are clear behind the break.

As I mentioned, no matter what PAGE_OFFSET is, if you link vmlinux
from the address of PAGE_OFFSET(that is what arm's link script in tree
does), the filter won't break anything.


Thanks,
--
Ming Lei
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