Re: [PATCH bpf-next v3 10/10] selftests/bpf: add file dynptr tests

[Eduard Zingerman <eddyz87@gmail.com>]

On Mon, 2025-10-20 at 23:25 +0100, Mykyta Yatsenko wrote:
> From: Mykyta Yatsenko <yatsenko@meta.com>
> 
> Introducing selftests for validating file-backed dynptr works as
> expected.
>  * validate implementation supports dynptr slice and read operations
>  * validate destructors should be paired with initializers
>  * validate sleepable progs can page in.
> 
> Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
> ---

[...]

> diff --git a/tools/testing/selftests/bpf/progs/file_reader.c b/tools/testing/selftests/bpf/progs/file_reader.c
> new file mode 100644
> index 000000000000..695ef6392771
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/file_reader.c
> @@ -0,0 +1,178 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
> +
> +#include <vmlinux.h>
> +#include <string.h>
> +#include <stdbool.h>
> +#include <bpf/bpf_tracing.h>
> +#include "bpf_misc.h"
> +#include "errno.h"
> +
> +char _license[] SEC("license") = "GPL";
> +
> +struct {
> +	__uint(type, BPF_MAP_TYPE_ARRAY);
> +	__uint(max_entries, 1);
> +	__type(key, int);
> +	__type(value, struct elem);
> +} arrmap SEC(".maps");
> +
> +struct {
> +	__uint(type, BPF_MAP_TYPE_RINGBUF);
> +	__uint(max_entries, 10000000);
> +} ringbuf SEC(".maps");

The test case lgtm, but a question: will it be possible to use an
array map instead of a ringbuf?  Just to avoid the need to allocate
and discard the pointer.

[...]

> diff --git a/tools/testing/selftests/bpf/progs/file_reader_fail.c b/tools/testing/selftests/bpf/progs/file_reader_fail.c
> new file mode 100644
> index 000000000000..32fe28ed2439
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/file_reader_fail.c

Thank you for adding these.

[...]