Re: [PATCH RESEND bpf-next v7 0/4] Add prog_kfunc feature probe

[Tao Chen <chen.dylane@gmail.com>]

在 2025/2/21 09:11, Eduard Zingerman 写道:
> On Thu, 2025-02-20 at 17:07 -0800, Andrii Nakryiko wrote:
>> On Tue, Feb 18, 2025 at 2:51 PM Eduard Zingerman <eddyz87@gmail.com> wrote:
>>>
>>> On Mon, 2025-02-17 at 13:21 +0800, Tao Chen wrote:
> 
> [...]
> 
>>> I tried the test enumerating all kfuncs in BTF and doing
>>> libbpf_probe_bpf_kfunc for BPF_PROG_TYPE_{KPROBE,XDP}.
>>> (Source code at the end of the email).
>>>
>>> The set of kfuncs returned for XDP looks correct.
>>> The set of kfuncs returned for KPROBE contains a few incorrect entries:
>>> - bpf_xdp_metadata_rx_hash
>>> - bpf_xdp_metadata_rx_timestamp
>>> - bpf_xdp_metadata_rx_vlan_tag
>>>
>>> This is because of a different string reported by verifier for these
>>> three functions.
>>>
>>> Ideally, I'd write some script looking for
>>> register_btf_kfunc_id_set(BPF_PROG_TYPE_***, kfunc_set)
>>> calls in the kernel source code and extracting the prog type /
>>> functions in the set, and comparing results of this script with
>>> output of the test below for all program types.
>>> But up to you if you'd like to do such rigorous verification or not.
>>>
>>> Otherwise patch-set looks good to me, for all patch-set:
>>>
>>> Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
>>
>> Shouldn't we fix the issue with those bpf_xdp_metadata_* kfuncs? Do
> 
> I assume Tao would post a v8 with the fix.
> 

Sure, will fix it.

>> you have details on what different string verifier reports?
> 
> The string is "metadata kfuncs require device-bound program\n".
> 
> [...]
> 


-- 
Best Regards
Tao Chen