Re: [dpdk-dev] [PATCH] app/testpmd: fix passing negative parameter to strerror

["Wei Hu (Xavier)" <xavier.huwei@huawei.com>]

On 2020/6/5 0:30, Ferruh Yigit wrote:
> On 6/4/2020 7:22 AM, Wei Hu (Xavier) wrote:
>> Currently, there are coverity defect warnings as blow:
>> Coverity issue:
>>    In nic_stats_clear function:
>>      CID 290021 (#1 of 1): Argument cannot be negative (NEGATIVE_RETURNS)
>>      5. negative_returns: ret is passed to a parameter that cannot be
>>         negative.
>>
>>      CID 289974 (#1 of 1): Argument cannot be negative (NEGATIVE_RETURNS)
>>      6. negative_returns: ret is passed to a parameter that cannot be
>>         negative.
>>
>>    In nic_xstats_clear function:
>>      CID 289985 (#1 of 1): Argument cannot be negative (NEGATIVE_RETURNS)
>>      5. negative_returns: ret is passed to a parameter that cannot be
>>         negative.
>>
>>      CID 289850 (#1 of 1): Argument cannot be negative (NEGATIVE_RETURNS)
>>      6. negative_returns: ret is passed to a parameter that cannot be
>>         negative.
> I guess these coverity IDs are from the internal coverity, because I can't find
> them in the public coverity.
> If it is internal, not sure about the benefit of documenting them in the commit
> log, since no one except huawei can access them. What do you think to remove all
> above reference?
Yes, these are internal covertiy defects information. Maybe we can remove
internal coverity CID xxxx and reserve the description of the defect in the
commit log.

By the way,  when we access the "View defects" on the page of the public 
coverity
https://scan.coverity.com/projects/dpdk-data-plane-development-kit?tab=overview 

, The browser prompts HTTP ERROR 403.
>> This patch fixes them by passing '-ret' to the function strerror() when ret
>> is negative.
>>
>> Fixes: af75078fece3 ("first public release")
>> Fixes: 9eb974221f44 ("app/testpmd: fix statistics after reset")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
>> ---
>>   app/test-pmd/config.c | 8 ++++----
>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
>> index 5381207..356d0d2 100644
>> --- a/app/test-pmd/config.c
>> +++ b/app/test-pmd/config.c
>> @@ -244,14 +244,14 @@ nic_stats_clear(portid_t port_id)
>>   	ret = rte_eth_stats_reset(port_id);
>>   	if (ret != 0) {
>>   		printf("%s: Error: failed to reset stats (port %u): %s",
>> -		       __func__, port_id, strerror(ret));
>> +		       __func__, port_id, strerror(-ret));
>>   		return;
>>   	}
>>   
>>   	ret = rte_eth_stats_get(port_id, &ports[port_id].stats);
>>   	if (ret != 0) {
>>   		printf("%s: Error: failed to get stats (port %u): %s",
>> -		       __func__, port_id, strerror(ret));
>> +		       __func__, port_id, strerror(-ret));
> Although in practice this may be the case, the 'rte_eth_stats_get()' function
> documentation doesn't guarantee that return value will be negative, it says:
>
> "
>   * @return
>   *   Zero if successful. Non-zero otherwise
> "
>
> To be accurate, what do you think to adding a negative check for 'ret' before
> doing '-ret'?
OK, we will add a negative check in V2.

Thanks, Xavier