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

[Ming Lei]

On Fri, Nov 8, 2013 at 7:44 AM, Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote:
> Axel Lin <axel.lin@xxxxxxxxxx> writes:
>> 2013/11/7 Ming Lei <tom.leiming@xxxxxxxxx>:
>>> Hi,
>>>
>>> On Thu, Nov 7, 2013 at 10:47 AM, Axel Lin <axel.lin@xxxxxxxxxx> wrote:
>>>>
>>>> hi Ming,
>>>> Seems CONFIG_PAGE_OFFSET is not configurabe in "make menuconfig".
>>>> And I found CONFIG_PAGE_OFFSET=0xC0000000 for all below configs...
>>>> $ make at91_dt_defconfig; grep  CONFIG_PAGE_OFFSET .config
>>>> $ make ep93xx_defconfig; grep  CONFIG_PAGE_OFFSET .config
>>>> $ make imx_v4_v5_defconfig; grep CONFIG_PAGE_OFFSET .config
>>>> $ make mxs_defconfig; grep CONFIG_PAGE_OFFSET .config
>>>> $ make omap2plus_defconfig; grep CONFIG_PAGE_OFFSET .config
>>>> $ make s3c6400_defconfig; grep CONFIG_PAGE_OFFSET .config
>>>> $ make at91x40_defconfig; grep CONFIG_PAGE_OFFSET .config
>>>> ( at91x40_defconfig is also arm7tdmi )
>>>
>>> Firstly it can be configured via VMSPLIT_3GVMSPLIT_2G/VMSPLIT_1G.
>>>
>>> Secondly, configurable or not isn't the point, and maybe some uclinux
>>> platforms do not use CONFIG_PAGE_OFFSET at all, but they should
>>> set it as a reasonable value or at least be below than the start link
>>> address of vmlinux.
>>
>> Hi Ming,
>>
>> I found in arch/arm/include/asm/memory.h:
>> CONFIG_PAGE_OFFSET is not used if !CONFIG_MMU.
>> So looks like setting CONFIG_PAGE_OFFSET to other value still won't work.
>
> This seems like the simplest solution, but it may mean you still have
> crap in /proc/kallsyms.
>
> Does it work for you?

Yes, it should work, but I am wondering if perf can work on uClinux.

Axel, could you post your .config?


Thanks,
-- 
Ming Lei
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