Re: [PATCH 2/2] selftests/bpf: Add regression test for queue/stack map size limit

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Multi-line comment opening `/*` is not on its own line.
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--- Patch [2]: [PATCH 2/2] selftests/bpf: Add regression test for queue/stack map size limit ---
commit e79d16bed784907a39f11792c9c1497efb8fd26f
Author: Yuan Chen <[email protected]>

selftests/bpf: Add regression test for queue/stack map size limit

This commit adds a regression test to verify that queue and stack maps reject
creation if their element storage size exceeds U32_MAX bytes. It tests both
queue and stack maps with an oversized configuration, ensuring they fail with
-E2BIG, and also verifies that a normal-sized map is successfully created.

> diff --git a/tools/testing/selftests/bpf/prog_tests/queue_stack_map.c b/tools/testing/selftests/bpf/prog_tests/queue_stack_map.c
> index 41441325e1794..6f8ac285e7196 100644
> --- a/tools/testing/selftests/bpf/prog_tests/queue_stack_map.c
> +++ b/tools/testing/selftests/bpf/prog_tests/queue_stack_map.c
[ ... ]
> @@ -101,8 +101,42 @@ static void test_queue_stack_map_by_type(int type)
>  	bpf_object__close(obj);
>  }
>  
> +static void test_queue_stack_map_alloc_check(void)
> +{
> +	LIBBPF_OPTS(bpf_map_create_opts, opts);
> +	const __u32 big_value = 1 << 20; /* 1MB */
> +	int fd, saved_errno;
> +
> +	/* Regression test for the u32 index overflow in queue/stack maps:

[Severity: Low]
This isn't a bug, but should this multi-line comment follow the BPF subsystem
comment style by placing the opening /* on its own line?

> +	 * a map whose element storage (max_entries * value_size) exceeds
> +	 * U32_MAX bytes must be rejected at creation time, otherwise the
> +	 * u32 head/tail index multiplication wraps and push/peek/pop
> +	 * address the wrong element. 8192 * 1MB = 8GB > U32_MAX.
> +	 */
> +	fd = bpf_map_create(BPF_MAP_TYPE_QUEUE, NULL, 0, big_value, 8192, &opts);

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=2