Re: [PATCH bpf-next 5/5] selftests/bpf: Test log_true_size with an error from blinding

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] selftests/bpf: standalone blinding_log.c added for single narrow test case
--

commit 34995a62836807ba96cd4bc1543b3812e415d382
Author: Qiliang Yuan <odys.yuan@gmail.com>

selftests/bpf: Test log_true_size with an error from blinding

This commit adds a BPF selftest checking that log_true_size includes the
error message emitted when constant blinding with bpf_jit_harden=2 pushes a
jump out of its 16-bit range.

> diff --git a/tools/testing/selftests/bpf/prog_tests/blinding_log.c b/tools/testing/selftests/bpf/prog_tests/blinding_log.c
> new file mode 100644
> index 0000000000000..658a8494dae5b
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/blinding_log.c
> @@ -0,0 +1,59 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* The verifier log of a prog whose constants are blinded */
> +
> +#include <test_progs.h>
> +#include <linux/filter.h>
> +#include "sysctl_helpers.h"
> +
> +#define NR_CONSTS 11000
> +#define LOG_SIZE 65536
> +
> +/*
> + * A prog of one function gets its constants blinded when its runtime is
> + * selected. Each 'r0 += 1' becomes 3 insns, which pushes the jump over them
> + * out of its 16-bit range. Serial, because it sets bpf_jit_harden.
> + */
> +void serial_test_blinding_log(void)

[Severity: Low]
This isn't a bug, but tools/testing/selftests/bpf/prog_tests/patch_list.c
already defines serial_test_patch_list() in the same directory to test
patch-list constant blinding while toggling /proc/sys/net/core/bpf_jit_harden
to 2 via sysctl_set_or_fail() and checking is_jit_enabled():

tools/testing/selftests/bpf/prog_tests/patch_list.c:
void serial_test_patch_list(void)
{
	if (test__start_subtest("line_and_func_info"))
		test_line_and_func_info();
	if (test__start_subtest("poke_descriptor"))
		test_poke_descriptor();
	if (test__start_subtest("classic_filter"))
		test_classic_filter();
}

Could this test case be added as a subtest inside serial_test_patch_list() in
tools/testing/selftests/bpf/prog_tests/patch_list.c instead of adding a
separate standalone file for a single test?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261102-bpf-blind-nops-fixes-v1-0-844300e42cdb@gmail.com?part=5