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SubjectRe: [PATCH] net: ena: initialize dim_sample
Date

Eric Dumazet <edumazet@google.com> writes:

> On Sun, Jan 8, 2023 at 3:38 PM Tom Rix <trix@redhat.com> wrote:
>>
>> clang static analysis reports this problem
>> drivers/net/ethernet/amazon/ena/ena_netdev.c:1821:2: warning:
>> Passed-by-value struct
>> argument contains uninitialized data (e.g., field:
>> 'comp_ctr') [core.CallAndMessage]
>> net_dim(&ena_napi->dim, dim_sample);
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> net_dim can call dim_calc_stats() which uses the comp_ctr
>> element,
>> so it must be initialized.
>
> This seems to be a dim_update_sample() problem really, when
> comp_ctr
> has been added...
>
> Your patch works, but we could avoid pre-initializing dim_sample
> in all callers,
> then re-writing all but one field...
>
> diff --git a/include/linux/dim.h b/include/linux/dim.h
> index
> 6c5733981563eadf5f06c59c5dc97df961692b02..4604ced4517268ef8912cd8053ac8f4d2630f977
> 100644
> --- a/include/linux/dim.h
> +++ b/include/linux/dim.h
> @@ -254,6 +254,7 @@ dim_update_sample(u16 event_ctr, u64
> packets, u64
> bytes, struct dim_sample *s)
> s->pkt_ctr = packets;
> s->byte_ctr = bytes;
> s->event_ctr = event_ctr;
> + s->comp_ctr = 0;
> }
>
> /**

Hi,

I'd rather go with Eric's solution to this issue than zero the
whole struct in ENA

Thanks,
Shay

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