[CRIU] [PATCH 4/4] arch: x86 -- Add proxification of vDSO calls

[Pavel Emelyanov]

> @@ -381,6 +392,30 @@ static int restore_priv_vma_content(pid_t pid)
>  		}
>  	}
>  
> +	/*
> +	 * Proxify vdso content.
> +	 */
> +	if (vdso_proxy->proxify) {
> +		void *base_to, *base_from;
> +
> +		base_to = decode_pointer(vma_premmaped_start(&vdso_proxy->vma_to->vma));
> +		base_from = decode_pointer(vma_premmaped_start(&vdso_proxy->sym_from->vma));
> +
> +		/*
> +		 * Fill new vDSO with content of run-time vDSO
> +		 */
> +		pr_debug("vdso: Copy run-time contents %p -> %p\n",
> +			 (void *)vdso_proxy->sym_rt.vma_start, base_to);
> +
> +		memcpy(base_to, (void *)vdso_proxy->sym_rt.vma_start,
> +		       symtable_vma_size(&vdso_proxy->sym_rt));
> +
> +		if (arch_proxify_vdso(base_to, base_from,
> +				      &vdso_proxy->sym_rt,
> +				      &vdso_proxy->sym_dumpee))
> +			return -1;

I don't get this. You put into task's VDSO address a VDSO-proxy with the memcpy above
and tune jump offsets with arch_proxify_vdso. Where is the new VDSO itself?

> +	}
> +