linux-kernel - [PATCH v3 2/3] selftests: soft-dirty: Add test for mprotect

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Date:   Thu, 21 Jul 2022 14:33:37 -0400
From:   Peter Xu <peterx@...hat.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     Nadav Amit <nadav.amit@...il.com>, peterx@...hat.com,
        Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>,
        Andrea Arcangeli <aarcange@...hat.com>
Subject: [PATCH v3 2/3] selftests: soft-dirty: Add test for mprotect

Add two soft-diryt test cases for mprotect() on both anon or file.

Signed-off-by: Peter Xu <peterx@...hat.com>
---
 tools/testing/selftests/vm/soft-dirty.c | 69 ++++++++++++++++++++++++-
 1 file changed, 68 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/vm/soft-dirty.c b/tools/testing/selftests/vm/soft-dirty.c
index 08ab62a4a9d0..7d93906aa43f 100644
--- a/tools/testing/selftests/vm/soft-dirty.c
+++ b/tools/testing/selftests/vm/soft-dirty.c
@@ -121,13 +121,78 @@ static void test_hugepage(int pagemap_fd, int pagesize)
 	free(map);
 }
 
+static void test_mprotect(int pagemap_fd, int pagesize, bool anon)
+{
+	const char *type[] = {"file", "anon"};
+	const char *fname = "./soft-dirty-test-file";
+	int test_fd;
+	char *map;
+
+	if (anon) {
+		map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE,
+			   MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+		if (!map)
+			ksft_exit_fail_msg("anon mmap failed\n");
+	} else {
+		unlink(fname);
+		test_fd = open(fname, O_RDWR | O_CREAT);
+		if (test_fd < 0) {
+			ksft_test_result_skip("Test %s huge page allocation\n", __func__);
+			return;
+		}
+		ftruncate(test_fd, pagesize);
+		map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE,
+			   MAP_SHARED, test_fd, 0);
+		if (!map)
+			ksft_exit_fail_msg("file mmap failed\n");
+	}
+
+	*map = 1;
+	ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1,
+			 "Test %s-%s dirty bit of new written page\n",
+			 __func__, type[anon]);
+	clear_softdirty();
+	ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0,
+			 "Test %s-%s soft-dirty clear after clear_refs\n",
+			 __func__, type[anon]);
+	mprotect(map, pagesize, PROT_READ);
+	ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0,
+			 "Test %s-%s soft-dirty clear after marking RO\n",
+			 __func__, type[anon]);
+	mprotect(map, pagesize, PROT_READ|PROT_WRITE);
+	ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0,
+			 "Test %s-%s soft-dirty clear after marking RW\n",
+			 __func__, type[anon]);
+	*map = 2;
+	ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1,
+			 "Test %s-%s soft-dirty after rewritten\n",
+			 __func__, type[anon]);
+
+	munmap(map, pagesize);
+
+	if (!anon) {
+		close(test_fd);
+		unlink(fname);
+	}
+}
+
+static void test_mprotect_anon(int pagemap_fd, int pagesize)
+{
+	test_mprotect(pagemap_fd, pagesize, true);
+}
+
+static void test_mprotect_file(int pagemap_fd, int pagesize)
+{
+	test_mprotect(pagemap_fd, pagesize, false);
+}
+
 int main(int argc, char **argv)
 {
 	int pagemap_fd;
 	int pagesize;
 
 	ksft_print_header();
-	ksft_set_plan(5);
+	ksft_set_plan(15);
 
 	pagemap_fd = open(PAGEMAP_FILE_PATH, O_RDONLY);
 	if (pagemap_fd < 0)
@@ -138,6 +203,8 @@ int main(int argc, char **argv)
 	test_simple(pagemap_fd, pagesize);
 	test_vma_reuse(pagemap_fd, pagesize);
 	test_hugepage(pagemap_fd, pagesize);
+	test_mprotect_anon(pagemap_fd, pagesize);
+	test_mprotect_file(pagemap_fd, pagesize);
 
 	close(pagemap_fd);
 
-- 
2.32.0