Re: [PATCH net-next] iavf: Avoid a memory allocation in iavf_print_link_message()

[Jesse Brandeburg]

On 10/3/2023 1:33 PM, Christophe JAILLET wrote:
> kasprintf() is much better.

cool! I just sent the patches and cc'd you earlier today.

> > your patch still shows these errors
>
> I built-tested the patch before sending, so this is strange.
>
> However, I got a similar feedback from Greg KH and the "kernel test 
> robot" for another similar patch.
>
> What version of gcc do you use?
> I use 12.3.0, and I suspect that the value range algorithm or how the 
> diagnostic is done has been improved in recent gcc.

Fedora gcc 12.3.1, with W=1 flag

gcc version 12.3.1 20230508 (Red Hat 12.3.1-1) (GCC)

[linux]$ make W=1 M=drivers/net/ethernet/intel/iavf
  CC [M]  drivers/net/ethernet/intel/iavf/iavf_main.o
  CC [M]  drivers/net/ethernet/intel/iavf/iavf_ethtool.o
  CC [M]  drivers/net/ethernet/intel/iavf/iavf_virtchnl.o
  CC [M]  drivers/net/ethernet/intel/iavf/iavf_fdir.o
  CC [M]  drivers/net/ethernet/intel/iavf/iavf_adv_rss.o
  CC [M]  drivers/net/ethernet/intel/iavf/iavf_txrx.o
  CC [M]  drivers/net/ethernet/intel/iavf/iavf_common.o
  CC [M]  drivers/net/ethernet/intel/iavf/iavf_adminq.o
  CC [M]  drivers/net/ethernet/intel/iavf/iavf_client.o
drivers/net/ethernet/intel/iavf/iavf_virtchnl.c: In function 
‘iavf_virtchnl_completion’:
drivers/net/ethernet/intel/iavf/iavf_virtchnl.c:1446:60: warning: ‘%s’ 
directive output may be truncated writing 4 bytes into a region of size 
between 1 and 11 [-Wformat-truncation=]
 1446 |                 snprintf(speed, IAVF_MAX_SPEED_STRLEN, "%d %s",
      |                                                            ^~
 1447 |                          link_speed_mbps, "Mbps");
      |                                           ~~~~~~
In function ‘iavf_print_link_message’,
    inlined from ‘iavf_virtchnl_completion’ at 
drivers/net/ethernet/intel/iavf/iavf_virtchnl.c:1965:4:
drivers/net/ethernet/intel/iavf/iavf_virtchnl.c:1446:17: note: 
‘snprintf’ output between 7 and 17 bytes into a destination of size 13
 1446 |                 snprintf(speed, IAVF_MAX_SPEED_STRLEN, "%d %s",
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1447 |                          link_speed_mbps, "Mbps");
      |                          ~~~~~~~~~~~~~~~~~~~~~~~~