Re: [dpdk-dev] [PATCH] net/enic: fix build with GCC 7.5

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

On 10/15/2021 12:16 PM, David Marchand wrote:
> On Fri, Oct 15, 2021 at 12:28 PM Ferruh Yigit <ferruh.yigit@intel.com> wrote:
>>
>> Build error:
>> ../drivers/net/enic/enic_fm_flow.c: In function 'enic_fm_flow_parse':
>> ../drivers/net/enic/enic_fm_flow.c:1467:24:
>>          error: 'dev' may be used uninitialized in this function
>>          [-Werror=maybe-uninitialized]
>>      struct rte_eth_dev *dev;
>>                          ^~~
>> ../drivers/net/enic/enic_fm_flow.c:1580:24:
>>          error: 'dev' may be used uninitialized in this function
>>          [-Werror=maybe-uninitialized]
>>      struct rte_eth_dev *dev;
>>                          ^~~
>> ../drivers/net/enic/enic_fm_flow.c:1599:24:
>>          error: 'dev' may be used uninitialized in this function
>>          [-Werror=maybe-uninitialized]
>>      struct rte_eth_dev *dev;
>>                          ^~~
>>
>> Build error looks like false positive, but to silence the compiler
>> initializing the pointer with NULL.
> 
> enic_fm_check_transfer_dst() contains branches where dev is not set
> and those branches return rte_flow_error_set return value.
> dev is dereferenced later based on this return value == 0.
> 
> So the compiler probably thinks that rte_flow_error_set may return 0.
> rte_flow_error_set is outside of compiler "view" at the moment it
> compiles enic_fm_flow.c, so the compiler making the assumption this
> function can return 0 is being prudent from my pov.
> 
> 
>>
>> Fixes: 7968917ccf64 ("net/enic: support meta flow actions to overrule destinations")
>>
>> Reported-by: David Marchand <david.marchand@redhat.com>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> 
> Your fix looks good in any case.
> 
> Reviewed-by: David Marchand <david.marchand@redhat.com>
> 

Applied to dpdk-next-net/main, thanks.