Commit c23ea617 authored by Muhammad Usama Anjum's avatar Muhammad Usama Anjum Committed by Andrew Morton
Browse files

selftests/mm: protection_keys: save/restore nr_hugepages settings 

Save and restore nr_hugepages before changing it during the test.  A test
should not change system wide settings.

Link: https://lkml.kernel.org/r/20240125154608.720072-5-usama.anjum@collabora.com


Fixes: 5f23f6d0 ("x86/pkeys: Add self-tests")
Signed-off-by: default avatarMuhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7d695b1c

tools/testing/selftests/mm/protection_keys.c

+34 −0
Original line number Diff line number Diff line
@@ -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);