shmem: dump shared memory before dumping namespaces

page_ids is a global variable and it is used to dump shared memroy,
process memory and ipc shared memory.

The problem is that an IPC namespace is dumped in a child process,
so page_ids isn't changed in a parent process. This patch is a quick
workaround this issue.
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/cr-dump.c

@@ -1834,6 +1834,16 @@ int cr_dump_tasks(pid_t pid)
 	if (dump_pstree(root_item))
 		goto err;
 
+	/*
+	 * TODO: cr_dump_shmem has to be called before dump_namespaces(),
+	 * because page_ids is a global variable and it is used to dump
+	 * ipc shared memory, but an ipc namespace is dumped in a child
+	 * process.
+	 */
+	ret = cr_dump_shmem();
+	if (ret)
+		goto err;
+
 	if (root_ns_mask)
 		if (dump_namespaces(root_item, root_ns_mask) < 0)
 			goto err;
@@ -1842,10 +1852,6 @@ int cr_dump_tasks(pid_t pid)
 	if (ret)
 		goto err;
 
-	ret = cr_dump_shmem();
-	if (ret)
-		goto err;
-
 	ret = fix_external_unix_sockets();
 	if (ret)
 		goto err;