[CRIU] Dealing with VDSO remap

[Pavel Emelyanov]

> No my concern was about the remapping of the vDSO and the non updating
> of kernel's reference to its base.
> 
> On my ppc64 system, the attached test case leads to a process's core
> dump when it is returning from the signal handler once the vDSO has been
> remapped.

Just for clarification -- is it specific of ARM and PPC? I mean, does it
crash on x86 too?

> I'd appreciate if you could give it a try on an ARM64 box/guest. I tried
> to set up a ARM64 guest on my side, but I failed to make it run :(
> My though is that the process should core dump on ARM64 since the
> sigreturn stack frame will point to its old base address.
> 
> I'm currently working on a kernel patch to handle the vDSO remapping,
> which could solve part of this issue (there is still a window which
> can't be addressed).
> 
> Thanks,
> Laurent.
>