[LTP] Re [PATCH] syscalls/sched_setscheduler04: new test for sched_setscheduler()

[zhaogongyi]

Hi!

> > >> > +static void test_sched_setscheduler02(void) {
> >> > +	pthread_t tid;
> >> > +
> >> > +	SAFE_PTHREAD_CREATE(&tid, NULL, thread_func, NULL);
> >> > +	SAFE_PTHREAD_JOIN(tid, NULL);
> >> > +}
> >> > +
> >> > +
> >> > +static void run(void)
> >> > +{
> >> > +	sched_prio = sched_get_priority_min(SCHED_POLICY);
> >>
> >> This can go in the setup function.
> >
> > If move it to setup function, we run the test with option "-I 200", it
> > will fail.
> 
> Why?

sched_prio is a global variable, and it increase in any running loop, thus it will be out of range and report:

sched_setscheduler04.c:52: TPASS: param.sched_priority == sched_prio (99)
sched_setscheduler04.c:53: TPASS: new_policy == EXP_POLICY (1)
sched_setscheduler04.c:34: TINFO: Setting of tid: 70774
sched_setscheduler04.c:40: TBROK: sched_setscheduler(70774, 1, ...) failed: EINVAL (22)

Summary:
passed   196
failed   0
broken   1
skipped  0
warnings 0


> >
> >>
> >> > +
> >> > +	test_sched_setscheduler01();
> >> > +	test_sched_setscheduler02();
> >>
> >> This should be replaced with .tcnt = 2 and .test. or else just merge
> >> them into run.
> >
> > Agree, I will fix it int the next version.
> >
> >>
> >> > +}
> >> > +
> >> > +static struct tst_test test = {
> >> > +	.test_all = run,
> >>
> >> We probably need to ensure CAP_SYS_NICE. Full details are in 'man 7
> >> sched'
> >>
> >> i.e. .caps = (struct tst_cap[]) {
> >>   TST_CAP(TST_CAP_REQ, CAP_SYS_NICE),
> >>    null
> >> }
> >>
> >
> > In this testcase, we just increase the priority, should we add the checking
> of capability?
> 
> For the test to run we need CAP_SYS_NICE. If you want to test that the
> priority can only be set when CAP_SYS_NICE is available, then that is a
> seperate test in my opinion.

Anybody can call nice() to increase the priority, i have test it with normal user and passed.

And if decrease the priority, the test will report EPERM when running with normal user.

Regards,
Gongyi