Re: [PATCH v14 22/22] selftests/vm: test correct behavior of pkey-0
On 07/17/2018 06:49 AM, Ram Pai wrote:
> Ensure pkey-0 is allocated on start. Ensure pkey-0 can be attached
> dynamically in various modes, without failures. Ensure pkey-0 can be
> freed and allocated.
>
> Signed-off-by: Ram Pai
> ---
> tools/testing/selftests/vm/protection_keys.c | 66
> +-
> 1 files changed, 64 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/vm/protection_keys.c
> b/tools/testing/selftests/vm/protection_keys.c
> index 569faf1..156b449 100644
> --- a/tools/testing/selftests/vm/protection_keys.c
> +++ b/tools/testing/selftests/vm/protection_keys.c
> @@ -999,6 +999,67 @@ void close_test_fds(void)
> return *ptr;
> }
>
> +void test_pkey_alloc_free_attach_pkey0(int *ptr, u16 pkey)
> +{
> + int i, err;
> + int max_nr_pkey_allocs;
> + int alloced_pkeys[NR_PKEYS];
> + int nr_alloced = 0;
> + int newpkey;
> + long size;
> +
> + assert(pkey_last_malloc_record);
> + size = pkey_last_malloc_record->size;
> + /*
> + * This is a bit of a hack. But mprotect() requires
> + * huge-page-aligned sizes when operating on hugetlbfs.
> + * So, make sure that we use something that's a multiple
> + * of a huge page when we can.
> + */
> + if (size >= HPAGE_SIZE)
> + size = HPAGE_SIZE;
> +
> +
> + /* allocate every possible key and make sure key-0 never got allocated
> */
> + max_nr_pkey_allocs = NR_PKEYS;
> + for (i = 0; i < max_nr_pkey_allocs; i++) {
> + int new_pkey = alloc_pkey();
> + assert(new_pkey != 0);
Missed these earlier. This needs to be pkey_assert(). We don't want
these tests to ever _actually_ crash.
> + /* attach key-0 in various modes */
> + err = sys_mprotect_pkey(ptr, size, PROT_READ, 0);
> + pkey_assert(!err);
> + err = sys_mprotect_pkey(ptr, size, PROT_WRITE, 0);
> + pkey_assert(!err);
> + err = sys_mprotect_pkey(ptr, size, PROT_EXEC, 0);
> + pkey_assert(!err);
> + err = sys_mprotect_pkey(ptr, size, PROT_READ|PROT_WRITE, 0);
> + pkey_assert(!err);
> + err = sys_mprotect_pkey(ptr, size, PROT_READ|PROT_WRITE|PROT_EXEC, 0);
> + pkey_assert(!err);
This is all fine.
> + /* free key-0 */
> + err = sys_pkey_free(0);
> + pkey_assert(!err);
This part is called out as undefined behavior in the manpage:
>An application should not call pkey_free() on any protection key
>which has been assigned to an address range by pkey_mprotect(2) and
>which is still in use. The behavior in this case is undefined and
>may result in an error.
I don't think we should be testing for undefined behavior.
> + newpkey = sys_pkey_alloc(0, 0x0);
> + assert(newpkey == 0);
> +}
> +
> void test_read_of_write_disabled_region(int *ptr, u16 pkey)
> {
> int ptr_contents;
> @@ -1144,10 +1205,10 @@ void
> test_kernel_gup_write_to_write_disabled_region(int *ptr, u16 pkey)
> void test_pkey_syscalls_on_non_allocated_pkey(int *ptr, u16 pkey)
> {
> int err;
> - int i = get_start_key();
> + int i;
>
> /* Note: 0 is the default pkey, so don't mess with it */
> - for (; i < NR_PKEYS; i++) {
> + for (i=1; i < NR_PKEYS; i++) {
> if (pkey == i)
> continue;
This seems to be randomly reverting earlier changes.
[PATCH v14 22/22] selftests/vm: test correct behavior of pkey-0
Ensure pkey-0 is allocated on start. Ensure pkey-0 can be attached
dynamically in various modes, without failures. Ensure pkey-0 can be
freed and allocated.
Signed-off-by: Ram Pai
---
tools/testing/selftests/vm/protection_keys.c | 66 +-
1 files changed, 64 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/vm/protection_keys.c
b/tools/testing/selftests/vm/protection_keys.c
index 569faf1..156b449 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -999,6 +999,67 @@ void close_test_fds(void)
return *ptr;
}
+void test_pkey_alloc_free_attach_pkey0(int *ptr, u16 pkey)
+{
+ int i, err;
+ int max_nr_pkey_allocs;
+ int alloced_pkeys[NR_PKEYS];
+ int nr_alloced = 0;
+ int newpkey;
+ long size;
+
+ assert(pkey_last_malloc_record);
+ size = pkey_last_malloc_record->size;
+ /*
+* This is a bit of a hack. But mprotect() requires
+* huge-page-aligned sizes when operating on hugetlbfs.
+* So, make sure that we use something that's a multiple
+* of a huge page when we can.
+*/
+ if (size >= HPAGE_SIZE)
+ size = HPAGE_SIZE;
+
+
+ /* allocate every possible key and make sure key-0 never got allocated
*/
+ max_nr_pkey_allocs = NR_PKEYS;
+ for (i = 0; i < max_nr_pkey_allocs; i++) {
+ int new_pkey = alloc_pkey();
+ assert(new_pkey != 0);
+
+ if (new_pkey < 0)
+ break;
+ alloced_pkeys[nr_alloced++] = new_pkey;
+ }
+ /* free all the allocated keys */
+ for (i = 0; i < nr_alloced; i++) {
+ int free_ret;
+
+ if (!alloced_pkeys[i])
+ continue;
+ free_ret = sys_pkey_free(alloced_pkeys[i]);
+ pkey_assert(!free_ret);
+ }
+
+ /* attach key-0 in various modes */
+ err = sys_mprotect_pkey(ptr, size, PROT_READ, 0);
+ pkey_assert(!err);
+ err = sys_mprotect_pkey(ptr, size, PROT_WRITE, 0);
+ pkey_assert(!err);
+ err = sys_mprotect_pkey(ptr, size, PROT_EXEC, 0);
+ pkey_assert(!err);
+ err = sys_mprotect_pkey(ptr, size, PROT_READ|PROT_WRITE, 0);
+ pkey_assert(!err);
+ err = sys_mprotect_pkey(ptr, size, PROT_READ|PROT_WRITE|PROT_EXEC, 0);
+ pkey_assert(!err);
+
+ /* free key-0 */
+ err = sys_pkey_free(0);
+ pkey_assert(!err);
+
+ newpkey = sys_pkey_alloc(0, 0x0);
+ assert(newpkey == 0);
+}
+
void test_read_of_write_disabled_region(int *ptr, u16 pkey)
{
int ptr_contents;
@@ -1144,10 +1205,10 @@ void test_kernel_gup_write_to_write_disabled_region(int
*ptr, u16 pkey)
void test_pkey_syscalls_on_non_allocated_pkey(int *ptr, u16 pkey)
{
int err;
- int i = get_start_key();
+ int i;
/* Note: 0 is the default pkey, so don't mess with it */
- for (; i < NR_PKEYS; i++) {
+ for (i=1; i < NR_PKEYS; i++) {
if (pkey == i)
continue;
@@ -1455,6 +1516,7 @@ 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_pkey_alloc_free_attach_pkey0,
};
void run_tests_once(void)
--
1.7.1
