Hi Muhammad,
On Thu, Jan 25, 2024 at 08:46:07PM +0500, Muhammad Usama Anjum wrote:
> Save and restore nr_hugepages before changing it during the test. A test
> should not change system wide settings.
>
> Fixes: 5f23f6d082a9 ("x86/pkeys: Add self-tests")
> Signed-off-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
> ---
> tools/testing/selftests/mm/protection_keys.c | 34 ++++++++++++++++++++
> 1 file changed, 34 insertions(+)
>
> diff --git a/tools/testing/selftests/mm/protection_keys.c b/tools/testing/selftests/mm/protection_keys.c
> index 48dc151f8fca8..f822ae31af22e 100644
> --- a/tools/testing/selftests/mm/protection_keys.c
> +++ b/tools/testing/selftests/mm/protection_keys.c
> @@ -54,6 +54,7 @@ int test_nr;
> u64 shadow_pkey_reg;
> int dprint_in_signal;
> char dprint_in_signal_buffer[DPRINT_IN_SIGNAL_BUF_SIZE];
> +char buf[256];
>
> void cat_into_file(char *str, char *file)
> {
> @@ -1744,6 +1745,38 @@ void pkey_setup_shadow(void)
> shadow_pkey_reg = __read_pkey_reg();
> }
>
> +void restore_settings_atexit(void)
> +{
> + cat_into_file(buf, "/proc/sys/vm/nr_hugepages");
> +}
> +
> +void save_settings(void)
> +{
> + int fd;
> + int err;
> +
> + if (geteuid())
> + return;
> +
> + fd = open("/proc/sys/vm/nr_hugepages", O_RDONLY);
> + if (fd < 0) {
> + fprintf(stderr, "error opening\n");
> + perror("error: ");
> + exit(__LINE__);
> + }
> +
> + /* -1 to guarantee leaving the trailing \0 */
> + err = read(fd, buf, sizeof(buf)-1);
> + if (err < 0) {
> + fprintf(stderr, "error reading\n");
> + perror("error: ");
> + exit(__LINE__);
> + }
> +
> + atexit(restore_settings_atexit);
> + close(fd);
> +}
> +
> int main(void)
> {
> int nr_iterations = 22;
> @@ -1751,6 +1784,7 @@ int main(void)
>
> srand((unsigned int)time(NULL));
>
> + save_settings();
> setup_handlers();
>
> printf("has pkeys: %d\n", pkeys_supported);
> --
> 2.42.0
>
This break the tests for me:
assert() at protection_keys.c::812 test_nr: 19 iteration: 1
running abort_hooks()...
This is because some of the tests fork, so on their atexit() they will set the
nr_hugepages back to the previous setting. Specifically the
test_pkey_alloc_exhaust() test.
Thanks,
Joey
