The patch titled
Subject: selftests/mm: add mseal test for no-discard madvise
has been added to the -mm mm-unstable branch. Its filename is
selftests-mm-add-mseal-test-for-no-discard-madvise.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-add-mseal-test-for-no-discard-madvise.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Pedro Falcato <pedro.falcato@xxxxxxxxx>
Subject: selftests/mm: add mseal test for no-discard madvise
Date: Wed, 7 Aug 2024 18:33:36 +0100
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@xxxxxxxxx
Signed-off-by: Pedro Falcato <pedro.falcato@xxxxxxxxx>
Cc: Jeff Xu <jeffxu@xxxxxxxxxxxx>
Cc: Kees Cook <kees@xxxxxxxxxx>
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/mm/mseal_test.c | 34 ++++++++++++++++++++++
1 file changed, 34 insertions(+)
--- a/tools/testing/selftests/mm/mseal_test.c~selftests-mm-add-mseal-test-for-no-discard-madvise
+++ a/tools/testing/selftests/mm/mseal_test.c
@@ -1731,6 +1731,38 @@ static void test_seal_discard_ro_anon(bo
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();
@@ -1822,6 +1854,8 @@ 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);
_
Patches currently in -mm which might be from pedro.falcato@xxxxxxxxx are
mseal-fix-is_madv_discard.patch
selftests-mm-add-mseal-test-for-no-discard-madvise.patch
