zdtm: add a new test case for growdown vma-s

This test case creates two consecutive grows down vmas with a hole
between them.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm.sh

@@ -100,6 +100,7 @@ static/sk-netlink
 static/proc-self
 static/grow_map
 static/grow_map02
+static/grow_map03
 static/stopped
 static/chroot
 static/chroot-file

test/zdtm/live/static/Makefile

@@ -102,6 +102,7 @@ TST_NOFILE	=				\
 		mem-touch			\
 		grow_map			\
 		grow_map02			\
+		grow_map03			\
 		tun				\
 		stopped				\
 		rtc				\

test/zdtm/live/static/grow_map03.c

+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc	= "Check that VMA-s with MAP_GROWSDOWN are restored correctly";
+const char *test_author	= "Andrew Vagin <avagin@openvz.org>";
+
+/*
+* This test case creates two consecutive grows down vmas with a hole
+* between them.
+*/
+
+int main(int argc, char **argv)
+{
+	char *start_addr, *addr1, *addr2;
+
+	test_init(argc, argv);
+
+	start_addr = mmap(NULL, PAGE_SIZE * 10, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	if (start_addr == MAP_FAILED) {
+		err("Can't mal a new region");
+		return 1;
+	}
+	munmap(start_addr, PAGE_SIZE * 10);
+
+	addr1 = mmap(start_addr + PAGE_SIZE * 5, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_GROWSDOWN, -1, 0);
+	addr2 = mmap(start_addr + PAGE_SIZE * 3, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_GROWSDOWN, -1, 0);
+
+	err("%p %p\n", addr1, addr2);
+
+	test_daemon();
+	test_waitsig();
+
+	pass();
+
+	return 0;
+}