[RFC v6 56/62] selftest/vm: detect no key violation on a freed key

[Ram Pai]

a access-denied key should not trigger any key violation
after the key has been freed.

Signed-off-by: Ram Pai <linux...@us.ibm.com>
---
 tools/testing/selftests/vm/protection_keys.c |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/tools/testing/selftests/vm/protection_keys.c 
b/tools/testing/selftests/vm/protection_keys.c
index bf27bcd..47c23cc 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -1026,6 +1026,30 @@ void 
test_read_of_access_disabled_region_with_page_already_mapped(int *ptr,
        expected_pkey_fault(pkey);
 }
 
+void test_read_of_access_disabled_but_freed_key_region(int *ptr, u16 pkey)
+{
+       int ptr_contents;
+
+       dprintf1("disabling access to PKEY[%02d], doing read @ %p\n",
+                        pkey, ptr);
+
+       /* read the content */
+       ptr_contents = read_ptr(ptr);
+       do_not_expect_pkey_fault();
+
+       /* deny key access */
+       pkey_access_deny(pkey);
+       ptr_contents = read_ptr(ptr);
+       dprintf1("*ptr: %d\n", ptr_contents);
+       expected_pkey_fault(pkey);
+
+       /* free the key without restoring access */
+       pkey_access_deny(pkey);
+       sys_pkey_free(pkey);
+       ptr_contents = read_ptr(ptr);
+       do_not_expect_pkey_fault();
+}
+
 void test_write_of_write_disabled_region(int *ptr, u16 pkey)
 {
        dprintf1("disabling write access to PKEY[%02d], doing write\n", pkey);
@@ -1333,6 +1357,7 @@ void test_mprotect_pkey_on_unsupported_cpu(int *ptr, u16 
pkey)
        test_pkey_syscalls_on_non_allocated_pkey,
        test_pkey_syscalls_bad_args,
        test_pkey_alloc_exhaust,
+       test_read_of_access_disabled_but_freed_key_region,
 };
 
 void run_tests_once(void)
-- 
1.7.1