Re: [dpdk-dev] [PATCH 1/2] app/testpmd: fix integer overflow during get DCB conf

["Min Hu (Connor)" <humin29@huawei.com>]

在 2021/4/25 10:05, Li, Xiaoyun 写道:
> Hi
> 
>> -----Original Message-----
>> From: Min Hu (Connor) <humin29@huawei.com>
>> Sent: Thursday, April 22, 2021 15:04
>> To: dev@dpdk.org
>> Cc: Yigit, Ferruh <ferruh.yigit@intel.com>; Li, Xiaoyun <xiaoyun.li@intel.com>
>> Subject: [PATCH 1/2] app/testpmd: fix integer overflow during get DCB conf
>>
>> From: Chengchang Tang <tangchengchang@huawei.com>
>>
>> In C, constant is treated as integer. Therefore, if nb_queque_pools is
>> ETH_32_POOLS, the shift here may cause integer overflow.
>>
>> Fixes: 1a572499beb6 ("app/testpmd: setup DCB forwarding based on traffic
>> class")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
>> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
>> ---
>>   app/test-pmd/testpmd.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c index
>> afa2a6b..6784160 100644
>> --- a/app/test-pmd/testpmd.c
>> +++ b/app/test-pmd/testpmd.c
>> @@ -3640,7 +3640,7 @@ get_eth_dcb_conf(portid_t pid, struct rte_eth_conf
>> *eth_conf,
>>   		for (i = 0; i < vmdq_rx_conf->nb_pool_maps; i++) {
>>   			vmdq_rx_conf->pool_map[i].vlan_id = vlan_tags[i];
>>   			vmdq_rx_conf->pool_map[i].pools =
>> -				1 << (i % vmdq_rx_conf->nb_queue_pools);
>> +				1ULL << (i % vmdq_rx_conf->nb_queue_pools);
> 
> In get_eth_dcb_conf(),
> vmdq_rx_conf->nb_queue_pools =
> 			(num_tcs ==  ETH_4_TCS ? ETH_32_POOLS : ETH_16_POOLS);
> 
> It will only be 16 or 32.
> So I don't think this patch is necessary unless you're going to use the value ETH_64_POOLS.
> 
Agreed, this patch can be abandoned, thanks.
>>   		}
>>   		for (i = 0; i < ETH_DCB_NUM_USER_PRIORITIES; i++) {
>>   			vmdq_rx_conf->dcb_tc[i] = i % num_tcs;
>> --
>> 2.7.4
> 
> .
>