vdso: x86 -- Skip areas with known not to be vdso

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Tested-by: Alexander Kartashov <alekskartashov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

arch/x86/vdso.c

@@ -126,6 +126,9 @@ int parasite_fixup_vdso(struct parasite_ctl *ctl, pid_t pid,
 		if ((vma->vma.prot & VDSO_PROT) != VDSO_PROT)
 			continue;
 
+		if (vma->vma.start > TASK_SIZE)
+			continue;
+
 		/*
 		 * I need to poke every potentially marked vma,
 		 * otherwise if task never called for vdso functions