Re: [PATCH bpf-next v4 09/10] selftests/bpf: move bpf_jit_harden helper into testing_helpers

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The refactored `set_bpf_jit_harden` function has been moved to a common helper file and stripped of its internal `ASSERT_FAIL` calls. However, its usage in the cleanup path of `check_blindness()` was not updated to check the return value. Consequently, if restoring the sysctl fails during cleanup, the test will silently leave the system-wide `bpf_jit_harden` configuration in an altered state.
--

--- Patch [9]: [PATCH bpf-next v4 09/10] selftests/bpf: move bpf_jit_harden helper into testing_helpers ---
commit 806a4cb4e9c458805fd71ac7ae0f57e00e8af6bc
Author: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>

selftests/bpf: move bpf_jit_harden helper into testing_helpers

Move set_bpf_jit_harden to testing helpers so that other selftests can
change the hardening configuration without re-implementing a helper.

> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c
> index 0222a9a5d0761..37c405fc2b0d2 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c
> @@ -227,42 +227,6 @@ static void check_incorrect_index(void)
>  	check_mid_insn_index();
>  }
>  
> -static int set_bpf_jit_harden(char *level)
> -{
> -	char old_level;
> -	int err = -1;
> -	int fd = -1;
> -
> -	fd = open("/proc/sys/net/core/bpf_jit_harden", O_RDWR | O_NONBLOCK);
> -	if (fd < 0) {
> -		ASSERT_FAIL("open .../bpf_jit_harden returned %d (errno=%d)", fd, errno);
> -		return -1;
> -	}

[Severity: Medium]
Since this function's internal ASSERT_FAIL() calls were removed when moving it
to testing_helpers.c, are we missing an error check in the cleanup path of
check_blindness() where it restores the sysctl?

tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c:check_blindness() {
    ...
cleanup:
    /* restore the old one */
    if (bpf_jit_harden != '@')
        set_bpf_jit_harden(&bpf_jit_harden);
    ...
}

If restoring the sysctl fails during cleanup, this will silently leave the
system-wide bpf_jit_harden configuration in an altered state. Should the return
value of set_bpf_jit_harden() in the cleanup path be checked and asserted?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260708-kasan-v4-0-d5c177ab8227@bootlin.com?part=9