Re: [PATCH bpf-next v2 2/2] selftests/bpf: Use bpf_program__clone() in veristat

[Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>]

On 2/24/26 02:03, Eduard Zingerman wrote:
> On Fri, 2026-02-20 at 11:18 -0800, Mykyta Yatsenko wrote:
>> From: Mykyta Yatsenko <yatsenko@meta.com>
>>
>> Replace veristat's per-program object re-opening with
>> bpf_program__clone().
>>
>> Previously, veristat opened a separate bpf_object for every program in a
>> multi-program object file, iterated all programs to enable only the
>> target one, and then loaded the entire object.
>>
>> Use bpf_object__prepare() once, then call bpf_program__clone() for each
>> program individually. This lets veristat load programs one at a time
>> from a single prepared object.
>>
>> The caller now owns the returned fd and closes it after collecting stats.
>> Remove the special single-program fast path and the per-file early exit
>> in handle_verif_mode() so all files are always processed.
>>
>> Split fixup_obj() into fixup_obj_maps() for object-wide map fixups that
>> must run before bpf_object__prepare(), and fixup_obj() for per-program
>> fixups (struct_ops masking, freplace type guessing) that run before each
>> bpf_program__clone() call.
>>
>> Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
>> ---
> I run selftests binaries through old and new veristat versions and see
> some discrepancies. csv files attached.
> It looks like there are some failures that are now not logged.
> There is also at-least one success -> failure transition and
> a bunch of failure -> success transitions.
> I see no such differences for sched_ext programs.
> Is this an expected behavior?
yes, the regressions are explained in the cover letter:
"""
Known regression:
- Program-containing maps (PROG_ARRAY, DEVMAP, CPUMAP) track
owner program type. Programs with incompatible attributes
loaded against a shared map will be rejected. This is
expected kernel behavior.
"""
in the previous version of this series, there were no regressions,
but to achieve that we had to be a little bit creative with maps
loading, have a look:
https://lore.kernel.org/all/20260212-veristat_prepare-v1-1-c351023fb0db@meta.com/
clone_prog_maps()

The improvements are explained in the sibling thread with Alexei
(again because of PROG_ARRAY type of maps)
>
> [...]