Re: [dpdk-dev] [PATCH v1] examples/ntb: fix build issue with GCC 13

[Jerin Jacob <jerinjacobk@gmail.com>]

On Thu, May 4, 2023 at 2:06 PM Guo, Junfeng <junfeng.guo@intel.com> wrote:
>
>
>
> > -----Original Message-----
> > From: jerinj@marvell.com <jerinj@marvell.com>
> > Sent: Tuesday, May 2, 2023 21:51
> > To: dev@dpdk.org; Wu, Jingjing <jingjing.wu@intel.com>; Guo, Junfeng
> > <junfeng.guo@intel.com>; Li, Xiaoyun <xiaoyun.li@intel.com>
> > Cc: thomas@monjalon.net; david.marchand@redhat.com;
> > ferruh.yigit@xilinx.com; stephen@networkplumber.org; Jerin Jacob
> > <jerinj@marvell.com>; stable@dpdk.org
> > Subject: [dpdk-dev] [PATCH v1] examples/ntb: fix build issue with GCC 13
> >
> > From: Jerin Jacob <jerinj@marvell.com>
> >
> > Fix the following build issue by not allowing nb_ids to be zero.
> > nb_ids can be zero based on rte_rawdev_xstats_get() API
> > documentation but it is not valid for the case when second
> > argument is NULL.
>
> Is this the new standard for GCC 13?

No. Looks like optimization from compiler. It is able to detect their
case for zero memory allocation.

>
> >
> > examples/ntb/ntb_fwd.c: In function 'ntb_stats_display':
> > examples/ntb/ntb_fwd.c:945:23: error: 'rte_rawdev_xstats_get'
> > accessing 8 bytes in a region of size 0 [-Werror=stringop-overflow=]
> >   945 | if (nb_ids != rte_rawdev_xstats_get(dev_id, ids, values, nb_ids)) {
> >       |
> > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > examples/ntb/ntb_fwd.c:945:23: note: referencing argument 3
> > of type 'uint64_t[0]' {aka 'long unsigned int[]'}
> > In file included from ../examples/ntb/ntb_fwd.c:17:
> > lib/rawdev/rte_rawdev.h:504:1: note: in a call to function
> > 'rte_rawdev_xstats_get'
> >   504 | rte_rawdev_xstats_get(uint16_t dev_id,
> >
> > Fixes: 5194299d6ef5 ("examples/ntb: support more functions")
> > Cc: stable@dpdk.org
> > Signed-off-by: Jerin Jacob <jerinj@marvell.com>
> > ---
> >  examples/ntb/ntb_fwd.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/examples/ntb/ntb_fwd.c b/examples/ntb/ntb_fwd.c
> > index f9abed28e4..5489c3b3cd 100644
> > --- a/examples/ntb/ntb_fwd.c
> > +++ b/examples/ntb/ntb_fwd.c
> > @@ -923,7 +923,7 @@ ntb_stats_display(void)
> >
> >       /* Get NTB dev stats and stats names */
> >       nb_ids = rte_rawdev_xstats_names_get(dev_id, NULL, 0);
> > -     if (nb_ids  < 0) {
> > +     if (nb_ids <= 0) {
>
> Should the one in func ntb_stats_clear also be updated non-zero?

Some reason compiler is not detecting it. I will fix in next version.


>
> >               printf("Error: Cannot get count of xstats\n");
> >               return;
> >       }
> > --
> > 2.40.1
>