Commit 8e63360d authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

selftests/timers/posix-timers: Add a test for exact allocation mode 



The exact timer ID allocation mode is used by CRIU to restore timers with a
given ID. Add a test case for it.

It's skipped on older kernels when the prctl() fails.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/8734fl2tkx.ffs@tglx
parent ec2d0c04

tools/testing/selftests/timers/posix_timers.c

+72 −1
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
 * Kernel loop code stolen from Steven Rostedt <srostedt@redhat.com>

 */

#define _GNU_SOURCE

#include <sys/prctl.h>

#include <sys/time.h>

#include <sys/types.h>

#include <stdio.h>
@@ -599,14 +600,84 @@ static void check_overrun(int which, const char *name) 
			 "check_overrun %s\n", name);

}



#include <sys/syscall.h>



static int do_timer_create(int *id)

{

	return syscall(__NR_timer_create, CLOCK_MONOTONIC, NULL, id);

}



static int do_timer_delete(int id)

{

	return syscall(__NR_timer_delete, id);

}



#ifndef PR_TIMER_CREATE_RESTORE_IDS

# define PR_TIMER_CREATE_RESTORE_IDS		77

# define PR_TIMER_CREATE_RESTORE_IDS_OFF	 0

# define PR_TIMER_CREATE_RESTORE_IDS_ON		 1

# define PR_TIMER_CREATE_RESTORE_IDS_GET	 2

#endif



static void check_timer_create_exact(void)

{

	int id;



	if (prctl(PR_TIMER_CREATE_RESTORE_IDS, PR_TIMER_CREATE_RESTORE_IDS_ON, 0, 0, 0)) {

		switch (errno) {

		case EINVAL:

			ksft_test_result_skip("check timer create exact, not supported\n");

			return;

		default:

			ksft_test_result_skip("check timer create exact, errno = %d\n", errno);

			return;

		}

	}



	if (prctl(PR_TIMER_CREATE_RESTORE_IDS, PR_TIMER_CREATE_RESTORE_IDS_GET, 0, 0, 0) != 1)

		fatal_error(NULL, "prctl(GET) failed\n");



	id = 8;

	if (do_timer_create(&id) < 0)

		fatal_error(NULL, "timer_create()");



	if (do_timer_delete(id))

		fatal_error(NULL, "timer_delete()");



	if (prctl(PR_TIMER_CREATE_RESTORE_IDS, PR_TIMER_CREATE_RESTORE_IDS_OFF, 0, 0, 0))

		fatal_error(NULL, "prctl(OFF)");



	if (prctl(PR_TIMER_CREATE_RESTORE_IDS, PR_TIMER_CREATE_RESTORE_IDS_GET, 0, 0, 0) != 0)

		fatal_error(NULL, "prctl(GET) failed\n");



	if (id != 8) {

		ksft_test_result_fail("check timer create exact %d != 8\n", id);

		return;

	}



	/* Validate that it went back to normal mode and allocates ID 9 */

	if (do_timer_create(&id) < 0)

		fatal_error(NULL, "timer_create()");



	if (do_timer_delete(id))

		fatal_error(NULL, "timer_delete()");



	if (id == 9)

		ksft_test_result_pass("check timer create exact\n");

	else

		ksft_test_result_fail("check timer create exact. Disabling failed.\n");

}



int main(int argc, char **argv)

{

	ksft_print_header();

	ksft_set_plan(18);

	ksft_set_plan(19);



	ksft_print_msg("Testing posix timers. False negative may happen on CPU execution \n");

	ksft_print_msg("based timers if other threads run on the CPU...\n");



	check_timer_create_exact();



	check_itimer(ITIMER_VIRTUAL, "ITIMER_VIRTUAL");

	check_itimer(ITIMER_PROF, "ITIMER_PROF");

	check_itimer(ITIMER_REAL, "ITIMER_REAL");