[LTP] hugetlb/hugefallocate: Add hugefallocate03 to stress test fallocate on hugetlbfs

[Cyril Hrubis]

Hi!
> > +	SAFE_SIGACTION(SIGBUS, &sa, NULL);
> > +
> > +	fault_mmap_addr = SAFE_MMAP(NULL, max_hpages * hpage_size,
> > +			PROT_READ | PROT_WRITE, MAP_SHARED,
> > +			fd, 0);
> > +
> > +	pthread_cleanup_push(thread_fault_cleanup, NULL);
> > +
> > +	while (1) {
> > +		tpage = ((long long)random()) % (max_hpages);
> > +
> > +		if (sigsetjmp(fault_jmp, 1) == 0) {
> > +			foo = *((char *)(fault_mmap_addr + (tpage * hpage_size)));
> > +			*((volatile char *)(fault_mmap_addr + (tpage * hpage_size))) = foo;
> > +		}
> 
> Save the original SIGBUS handler and restore it upon thread termination or in
> cleanup. If SIGBUS is raised after this thread terminates, siglongjmp() jumps
> to an invalid stack.

More generally we can just remove all the thread cleanup registration
and cancelation points if we just do:

static volatile int run;

...

void *pthread_func(void *)
{
	...

	while (run) {
		...
	}

	SAFE_MUNMAP(...);
	reutrn NULL;
}

The main thread can then stop all three threads by setting run = 0 and
the cleanup runs without the pthread cleanup complexity.

-- 
Cyril Hrubis
chrubis@suse.cz