Re: [PATCH bpf-next 2/3] bpf: Check tail zero of bpf_prog_info

[Leon Hwang]

On 3/6/26 23:37, bot+bpf-ci@xxxxxxxxxx wrote:
>> Fix it by changing sizeof(info) to
>> offsetofend(struct bpf_prog_info, attach_btf_id).
>>
>> Fixes: b79c9fc9551b ("bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP")
> 
> Is this the right commit for the Fixes: tag?
> 
> The change avoids the trailing padding that exists because struct
> bpf_prog_info has 4 bytes of padding at its end, so sizeof(info) (232)
> differs from offsetofend(struct bpf_prog_info, attach_btf_id) (228).
> 
> That trailing padding first appeared when __u32 verified_insns was
> appended after the last __u64 member (recursion_misses).  Before that,
> the struct ended on an 8-byte-aligned member and had no trailing
> padding.
> 
> b79c9fc9551b only appended two further __u32 fields (attach_btf_obj_id,
> attach_btf_id), while the 4-byte trailing padding already existed and
> was unchanged.
> 
> Would this be more accurate?
> 
>   Fixes: aba64c7da983 ("bpf: Add verified_insns to bpf_prog_info and fdinfo")
> 
> 
Agreed.

Will update the Fixes tag in the next revision.

Thanks,
Leon