Re: [LTP] [PATCH v3 1/9] syscalls: Add epoll_create03

[Petr Vorel <pvorel@suse.cz>]

Hi Cyril,

> Test that checks that we get EMFILE when limit on per-process file
> descriptors is hit.

+1.

...
> +++ b/testcases/kernel/syscalls/epoll_create/epoll_create03.c
> @@ -0,0 +1,72 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2026 Cyril Hrubis <chrubis@suse.cz>
> + */
> +
> +/*\
> + * Verify that :manpage:epoll_create() fails with EMFILE when the per-process
Please add 2 to the manpage link.

:manpage:epoll_create(2)

Without it it's not working (plain text instead of link).
Can be changed before merge.

> + * limit on the number of open file descriptors has been reached.
> + */
> +
> +#include <stdlib.h>
> +#include <sys/epoll.h>
> +
> +#include "tst_test.h"
> +#include "lapi/epoll.h"
> +#include "lapi/syscalls.h"
> +
> +#include "epoll_create.h"
> +
> +static int *fds;
> +static int nfds;
> +static long maxfds;
> +
> +static void setup(void)
> +{
> +	int fd;
> +
> +	variant_info();
> +
> +	maxfds = SAFE_SYSCONF(_SC_OPEN_MAX);
> +	fds = SAFE_MALLOC(maxfds * sizeof(int));
> +	memset(fds, -1, maxfds * sizeof(int));
> +
> +	fds[0] = SAFE_OPEN("dummy", O_RDWR | O_CREAT, 0700);
> +	nfds = 1;
> +
> +	for (int i = 1; i < maxfds; i++) {
> +		fd = dup(fds[0]);
> +		if (fd == -1)
> +			break;
> +		fds[nfds++] = fd;
> +	}

How many files are created is done via `ulimit -n`, right? (not sure if there
is file for it in /proc/sys).
Would it be worth we check that? Or at least check that at least 2 files were
opened? Maybe this check should be rather put into dup03.c.

Or maybe to print how many descriptors was created?
tst_res(TINFO, "Created %d file descriptors", nfds);

> +}
> +
> +static void run(void)
> +{
> +	TST_EXP_FAIL2(do_epoll_create(1), EMFILE,
> +		      "epoll_create(1) with exhausted fds");

Otherwise LGTM.
Reviewed-by: Petr Vorel <pvorel@suse.cz>

Kind regards,
Petr

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