allocate_thp(self->aligned, self->pmdsize);
+	if (ret)
+		SKIP(return, "Failed to allocate THP");
+
+	/* Partial mprotect - make middle page read-only */
+	ret = mprotect((char *)self->aligned + self->pagesize, self->pagesize, PROT_READ);
+	ASSERT_EQ(ret, 0);
+
+	/* Verify we can still write to non-protected pages */
+	ptr[0] = 0xDD;
+	ptr[self->pmdsize - 1] = 0xEE;
+
+	ASSERT_EQ(ptr[0], (unsigned char)0xDD);
+	ASSERT_EQ(ptr[self->pmdsize - 1], (unsigned char)0xEE);
+
+	log_and_check_pmd_split(_metadata, self->split_pmd_before,
+		self->split_pmd_failed_before);
+}
+
 TEST_HARNESS_MAIN
-- 
2.47.3[RFC v2 18/21] selftests/mm: add partial_mprotect test for change_pmd_rangeUsama Arif <usama.arif@linux.dev> undefinedAndrew Morton <akpm@linux-foundation.org>, david@kernel.org, lorenzo.stoakes@oracle.com, willy@infradead.org, linux-mm@kvack.org undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined’"†ŸJ