From: Pedro Falcato <pedro.falcato@gmail.com>
Date: Wed, 7 Aug 2024 17:33:36 +0000 (+0100)
Subject: selftests/mm: add mseal test for no-discard madvise
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0c8c4e47147f211e8ee361dc9bce7e5a15682f1f;p=users%2Fjedix%2Flinux-maple.git

selftests/mm: add mseal test for no-discard madvise

Add an mseal test for madvise() operations that aren't considered
"discard" (e.g purely advisory ops such as MADV_RANDOM).

Link: https://lkml.kernel.org/r/20240807173336.2523757-3-pedro.falcato@gmail.com
Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/tools/testing/selftests/mm/mseal_test.c b/tools/testing/selftests/mm/mseal_test.c
index bfcea5cf9a48..e70539c8bede 100644
--- a/tools/testing/selftests/mm/mseal_test.c
+++ b/tools/testing/selftests/mm/mseal_test.c
@@ -1720,6 +1720,38 @@ static void test_seal_discard_ro_anon(bool seal)
 	REPORT_TEST_PASS();
 }
 
+static void test_seal_madvise_nodiscard(bool seal)
+{
+	void *ptr;
+	unsigned long page_size = getpagesize();
+	unsigned long size = 4 * page_size;
+	int ret;
+
+	setup_single_address(size, &ptr);
+	FAIL_TEST_IF_FALSE(ptr != (void *)-1);
+
+	if (seal) {
+		ret = seal_single_address(ptr, size);
+		FAIL_TEST_IF_FALSE(!ret);
+	}
+
+	/*
+	 * Test a random madvise flag like MADV_RANDOM that does not touch page
+	 * contents (and thus should work for msealed VMAs). RANDOM also happens to
+	 * share bits with other discard-ish flags like REMOVE.
+	 */
+	ret = sys_madvise(ptr, size, MADV_RANDOM);
+	FAIL_TEST_IF_FALSE(!ret);
+
+	ret = sys_munmap(ptr, size);
+	if (seal)
+		FAIL_TEST_IF_FALSE(ret < 0);
+	else
+		FAIL_TEST_IF_FALSE(!ret);
+
+	REPORT_TEST_PASS();
+}
+
 int main(int argc, char **argv)
 {
 	bool test_seal = seal_support();
@@ -1811,6 +1843,8 @@ int main(int argc, char **argv)
 	test_seal_mremap_move_fixed_zero(true);
 	test_seal_mremap_move_dontunmap_anyaddr(false);
 	test_seal_mremap_move_dontunmap_anyaddr(true);
+	test_seal_madvise_nodiscard(false);
+	test_seal_madvise_nodiscard(true);
 	test_seal_discard_ro_anon(false);
 	test_seal_discard_ro_anon(true);
 	test_seal_discard_ro_anon_on_rw(false);