[CRIU] [PATCH 2/4] Make vDSO warning behave as such

[Christopher Covington]

Hi Cyrill,

On 07/11/2014 12:08 PM, Cyrill Gorcunov wrote:
> On Fri, Jul 11, 2014 at 12:05:01PM -0400, Christopher Covington wrote:
>>>
>>> So that this patch doesn't solve the main problem, right? With patch
>>> applied dump will pass but then srgfault on restore. That said I need
>>> some help in resolving issue on arm machine. Mind to take a look what
>>> exactly causes sigsegv once time permit?
>>
>> One quick data point is that if I define VDSO for aarch64 and create symlinks
>> to the x86 vdso files from arch/aarch64, vdso00 and vdso01 pass on 3.15.0-rc7+.
>
> Good to know! The problem is that I'm reworking vdso code (because there a change
> coming from the kernel side soon which will make code a bit more complicated) so
> if current x86 code works for arm then probably we could copy it into arm and
> then simplify removing all unneded things (as far as I remember on arm vdso
> code was rather a stub doing nothing, no?).

What change are you talking about?

The 32-bit arm code was a stub but those VDSO patches may get merged soon.
aarch64 did not use the stub.

There are some aarch64 VDSO changes coming up:

http://git.kernel.org/cgit/linux/kernel/git/arm64/linux.git/commit/?id=8715493852783358ef8656a0054a14bf822509cf
http://git.kernel.org/cgit/linux/kernel/git/arm64/linux.git/commit/?id=2fea7f6c98f5957e539eb8aa0ce849729b900342
http://git.kernel.org/cgit/linux/kernel/git/arm64/linux.git/commit/?id=601255ae3c98fdeeee3a8bb4696425e4f868b4f1
http://git.kernel.org/cgit/linux/kernel/git/arm64/linux.git/commit/?id=ad789ba5f7086138461420d2156478d33fb61077

As far as I can tell the main impact is that the relative order of vdso and
vvar is reversed (I believe this is also the case for x86_32). For dumping I
can trivially extend a sanity check. For restoring my progress has been
slower. My first instinct is to break the vdso and vvar handling apart, but do
you have any different suggestions?

Thanks,
Christopher

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