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

[linuxtestproject.agent@gmail.com]

Hi Pavithra,

On Wed Sep 23 13:31:50 2026 +0530, Pavithra wrote:
> hugetlb/hugefallocate: Add hugefallocate03 to stress test fallocate on hugetlbfs

> +static int fd = -1;
> +static unsigned long max_hpages;
> +static long hpage_size;
> +static void *thread_fallocate(void *arg)

Add a blank line between variable declarations and function definitions.

> +	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.

> +	while (1) {
> +		addr = mmap(NULL, max_hpages * hpage_size,
> +				PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
> +		if (addr != MAP_FAILED)
> +			SAFE_MUNMAP(addr, max_hpages * hpage_size);
> +
> +		pthread_testcancel();
> +	}

Use SAFE_MMAP() instead of mmap() and drop the MAP_FAILED check.

> +	nr_hpages_free = SAFE_READ_MEMINFO(MEMINFO_HPAGE_FREE);
> +	max_hpages = MIN(nr_hpages_free, MAX_PAGES_TO_USE);
> +	free_before = nr_hpages_free;
> +	rsvd_before = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
> +
> +	/* First preallocate file with max_hpages pages */
> +	err = fallocate(fd, 0, 0, hpage_size * max_hpages);

Because .hugepages uses TST_REQUEST, nr_hpages_free and max_hpages can be 0.
When max_hpages is 0, fallocate() fails with EINVAL (causing TBROK instead of
TCONF), and the worker threads divide by zero. Add a check to abort with
tst_brk(TCONF, ...) when max_hpages is 0.

Verdict - Needs revision

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