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.
Fixes: 282faf61a053 ("net: ena: switch to dim algorithm for rx adaptive interrupt moderation")
Signed-off-by: Tom Rix <[email protected]>
---
drivers/net/ethernet/amazon/ena/ena_netdev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index e8ad5ea31aff..938184465eae 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -1805,7 +1805,7 @@ static void ena_dim_work(struct work_struct *w)
static void ena_adjust_adaptive_rx_intr_moderation(struct ena_napi *ena_napi)
{
- struct dim_sample dim_sample;
+ struct dim_sample dim_sample = {};
struct ena_ring *rx_ring = ena_napi->rx_ring;
if (!rx_ring->per_napi_packets)
--
2.27.0
On Sun, Jan 8, 2023 at 3:38 PM Tom Rix <[email protected]> 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;
}
/**
Sun, Jan 08, 2023 at 03:38:43PM CET, [email protected] 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.
>
>Fixes: 282faf61a053 ("net: ena: switch to dim algorithm for rx adaptive interrupt moderation")
>Signed-off-by: Tom Rix <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
On 1/10/23 8:58 AM, Shay Agroskin wrote:
>
> Eric Dumazet <[email protected]> writes:
>
>> On Sun, Jan 8, 2023 at 3:38 PM Tom Rix <[email protected]> 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
Please look at the other callers of dim_update_sample. The common
pattern is to initialize the struct.
This alternative will work, but the pattern of initializing the struct
the other (~20) callers should be refactored.
Tom
>
> Thanks,
> Shay
>
Eric Dumazet <[email protected]> writes:
> On Sun, Jan 8, 2023 at 3:38 PM Tom Rix <[email protected]> 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
Tom Rix <[email protected]> writes:
> On 1/10/23 8:58 AM, Shay Agroskin wrote:
>>
>> Eric Dumazet <[email protected]> writes:
>>
>>> On Sun, Jan 8, 2023 at 3:38 PM Tom Rix <[email protected]>
>>> 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
>
> Please look at the other callers of dim_update_sample. The
> common
> pattern is to initialize the struct.
>
> This alternative will work, but the pattern of initializing the
> struct
> the other (~20) callers should be refactored.
>
> Tom
>
While Eric's patch might be bigger if you also remove the
pre-initialization in the other drivers, the Linux code itself
would be smaller (granted not significantly) and
it make less room for pitfalls in adding DIM support in other
drivers.
Is there a good argument against using Eric's patch other than
'the other patch would be bigger' ?
Shay
>>
>> Thanks,
>> Shay
>>
On 1/11/23 12:46 AM, Shay Agroskin wrote:
>
> Tom Rix <[email protected]> writes:
>
>> On 1/10/23 8:58 AM, Shay Agroskin wrote:
>>>
>>> Eric Dumazet <[email protected]> writes:
>>>
>>>> On Sun, Jan 8, 2023 at 3:38 PM Tom Rix <[email protected]> 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
>>
>> Please look at the other callers of dim_update_sample. The common
>> pattern is to initialize the struct.
>>
>> This alternative will work, but the pattern of initializing the struct
>> the other (~20) callers should be refactored.
>>
>> Tom
>>
>
> While Eric's patch might be bigger if you also remove the
> pre-initialization in the other drivers, the Linux code itself would
> be smaller (granted not significantly) and
> it make less room for pitfalls in adding DIM support in other drivers.
>
> Is there a good argument against using Eric's patch other than 'the
> other patch would be bigger' ?
No, I think it a better approach and if Eric can take it forward that
would be great.
However when you start refactoring, it may grow larger than the single fix.
For instance, passing the structure by value could be changed to passing
by reference.
Tom
>
> Shay
>
>>>
>>> Thanks,
>>> Shay
>>>
>