netdev - Re: [PATCH net] bpf: don't zero out the info struct in bpf_obj_get_info_by

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Date:   Wed, 26 Jul 2017 01:29:50 +0200
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Jakub Kicinski <jakub.kicinski@...ronome.com>
CC:     netdev@...r.kernel.org, oss-drivers@...ronome.com,
        alexei.starovoitov@...il.com, kafai@...com
Subject: Re: [PATCH net] bpf: don't zero out the info struct in bpf_obj_get_info_by_fd()

On 07/26/2017 01:15 AM, Jakub Kicinski wrote:
> On Wed, 26 Jul 2017 00:59:49 +0200, Daniel Borkmann wrote:
>>> @@ -418,6 +420,8 @@ static void test_bpf_obj_id(void)
>>>    		nr_id_found++;
>>>
>>>    		err = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &info_len);
>>> +		prog_infos[i].jited_prog_insns = 0;
>>> +		prog_infos[i].xlated_prog_insns = 0;
>>
>> Can you elaborate why this one above is needed?
>
> Ah, I removed the comment about it at the last minute.  The check below
> compares the info we get here with info we got reading the programs in
> the earlier loop - using memcmp().

Yep, makes sense. I mistook it for 'length' given it is not NULL but 0,
but that is due to __aligned_u64. ;) Anyway, thanks for clarifying.

Acked-by: Daniel Borkmann <daniel@...earbox.net>