vdso/ia32: Don't unmap rt-vdso

Found with fault-injected jump trampolines in vdso,
that on ia32 tests rt-vdso got unmapped.
I've fixed it previously, but have forgot it during
debugging vdso cleanup.

Fixes: commit 8544895a ("ia32/restorer: move 32-bit pie unmap to x86")
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/arch/x86/restorer_unmap.S

@@ -6,6 +6,7 @@ ENTRY(__export_unmap_compat)
 	.code32
 	mov	bootstrap_start, %ebx
 	mov	bootstrap_len, %ecx
+	sub	vdso_rt_size, %ecx
 	movl	$__NR32_munmap, %eax
 	int	$0x80
 	int	$0x03 /* Guard */

criu/pie/restorer.c

@@ -1009,7 +1009,7 @@ static void restore_posix_timers(struct task_restore_args *args)
  * trap us on the exit from sys_munmap.
  */
 #ifdef CONFIG_VDSO
-static unsigned long vdso_rt_size;
+unsigned long vdso_rt_size = 0;
 #else
 #define vdso_rt_size	(0)
 #endif