Re: [PATCH v2] net/tap: resolve stringop-overflow with gcc 12 on ppc64le

[Ferruh Yigit <ferruh.yigit@amd.com>]

On 10/6/2023 7:31 PM, David Christensen wrote:
> 
> 
> On 9/29/23 6:48 AM, Ferruh Yigit wrote:
>> On 6/7/2023 7:47 PM, Ferruh Yigit wrote:
>>> On 5/16/2023 10:55 AM, Ferruh Yigit wrote:
>>>> On 5/16/2023 2:28 AM, Stephen Hemminger wrote:
>>>>> On Tue, 16 May 2023 00:35:56 +0100
>>>>> Ferruh Yigit <ferruh.yigit@amd.com> wrote:
>>>>>
>>>>>> Yes only some scripts and possible applications that hotplug tap
>>>>>> interface with hardcoded parameters may impacted, don't know how
>>>>>> big is
>>>>>> this amount but this ends up breaking something that was working
>>>>>> before
>>>>>> upgrading DPDK for them.
>>>>>>
>>>>>> And I believe the motivation is weak to break the behavior.
>>>>>>
>>>>>> Won't it be better to update 'rte_ether_unformat_addr()' to accept
>>>>>> more
>>>>>> flexible syntax, and use it? Is there any disadvantage of this
>>>>>> approach?
>>>>>
>>>>> It is already more flexible than the standard ether_aton().
>>>>
>>>> I mean to accept single chars, as 'tap' currently does, like
>>>> "a:a:a:a:a:a".
>>>>
>>>> Agree that impact of tap change is small, but if we can eliminate it
>>>> completely without any side affect, why not?
>>>>
>>>>
>>>> As accepting single char will be expanding 'rte_ether_unformat_addr()'
>>>> capability, it will be backward compatible, am I missing anything?
>>>>
>>>
>>> Hi David,
>>>
>>> If API update is not planned, what do you think to just solve the build
>>> error without changing functionality with a change something like below:
>>>
>>> ```
>>>   -       (strlen(mac_byte) == strspn(mac_byte,
>>>   -                       ETH_TAP_CMP_MAC_FMT))) {
>>>   +       (strlen(mac_byte) == strspn(mac_byte, ETH_TAP_CMP_MAC_FMT)) &&
>>>   +                       index < RTE_ETHER_ADDR_LEN) {
>>>
>>> ```
>>
>> Hi David,
>>
>> If you can confirm above fixes the issue, I can send a patch for it.
> 
> Confirmed that your proposed change resolves the build issue on ppc64le.
>  Appreciate if you can submit the patch.
> 
> 

Thanks for checking, but Stephen updated the 'rte_ether_unformat_addr()'
API [1] and sent a new version of this patch [2], which is merged in
next-net [3] now.
Build error for PPC should be fixed now.


[1]
https://patchwork.dpdk.org/project/dpdk/patch/20231003202909.391330-3-stephen@networkplumber.org/

[2]
https://patchwork.dpdk.org/project/dpdk/patch/20231003202909.391330-5-stephen@networkplumber.org/

[3]
https://git.dpdk.org/next/dpdk-next-net/log/