[CRIU] [PATCH 3/3] arm64: detect vDSO remaps

[Christopher Covington]

Hi Cyrill,

On 03/12/2014 02:16 AM, Cyrill Gorcunov wrote:
> On Wed, Mar 12, 2014 at 10:15:13AM +0400, Alexander Kartashov wrote:
>>>> This patch copes with this problem by adjusting the task struct
>>>> when the vDSO area is remapped.
>>> What a crap ;) Could you point which exactly variable in task struct
>>> bound to vdso address?
>>
>> I'm sorry it's not task struct but mm struct but this doesn't make
>> any difference. The problem initialization is this
>> http://lxr.free-electrons.com/source/arch/arm64/kernel/vdso.c#L171
> 
> So we will meet the same problem on x86-32 ;) I guess we rather need
> prctl extension for that which would allow to do user-space
> 
>  - remap vdso into a new place (setting up mm::context.vdso to null
>    or something, to disable vdso handling until mm::context.vdso reassigned)
>  - call prctl and set up new mm::context.vdso value
> 
> need to think...

What makes you propose this alternative? Do you think Alexander's approach
would constitute and ABI change and not be accepted upstream, or does it not
port well to x86 LP32, or something else?

Thanks,
Christopher

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