RE: [PATCH] ice/base: fix gcc 12 warning stringop-overflow

["Wu, WenxuanX" <wenxuanx.wu@intel.com>]

> -----Original Message-----
> From: Wu, WenxuanX <wenxuanx.wu@intel.com>
> Sent: 2022年6月20日 9:39
> To: Zhang, Qi Z <qi.z.zhang@intel.com>; Yang, Qiming
> <qiming.yang@intel.com>; dev@dpdk.org; thomas@monjalon.net
> Cc: stephen@networkplumber.org; stable@dpdk.org
> Subject: RE: [PATCH] ice/base: fix gcc 12 warning stringop-overflow
> 
> Hi all,
> 
> The warning  below gcc 12 :
>     inlined from ‘ice_add_adv_recipe’
> at ../drivers/net/ice/base/ice_switch.c:7951:11,
>     inlined from ‘ice_add_adv_rule’
> at ../drivers/net/ice/base/ice_switch.c:8911:11:
> ../drivers/net/ice/base/ice_switch.c:7220:61: error: writing 1 byte into a
> region of size 0 [-Werror=stringop-overflow=]
>  7220 |                         buf[recps].content.lkup_indx[i + 1] = entry->fv_idx[i];
>       |
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
> In file included from ../drivers/net/ice/base/ice_controlq.h:8,
>                  from ../drivers/net/ice/base/ice_type.h:54,
>                  from ../drivers/net/ice/base/ice_common.h:8,
>                  from ../drivers/net/ice/base/ice_switch.h:8,
>                  from ../drivers/net/ice/base/ice_switch.c:5:
> ../drivers/net/ice/base/ice_adminq_cmd.h: In function ‘ice_add_adv_rule’:
> ../drivers/net/ice/base/ice_adminq_cmd.h:744:12: note: at offset 5 into
> destination object ‘lkup_indx’ of size 5
>   744 |         u8 lkup_indx[5];
>       |            ^~~~~~~~~
> In function ‘ice_add_sw_recipe’,
>     inlined from ‘ice_add_adv_recipe’
> at ../drivers/net/ice/base/ice_switch.c:7951:11,
>     inlined from ‘ice_add_adv_rule’
> at ../drivers/net/ice/base/ice_switch.c:8911:11:
> ../drivers/net/ice/base/ice_switch.c:7220:61: error: writing 1 byte into a
> region of size 0 [-Werror=stringop-overflow=]
>  7220 |                         buf[recps].content.lkup_indx[i + 1] = entry->fv_idx[i];
>       |
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
> ../drivers/net/ice/base/ice_adminq_cmd.h: In function ‘ice_add_adv_rule’:
> ../drivers/net/ice/base/ice_adminq_cmd.h:744:12: note: at offset [6, 254]
> into destination object ‘lkup_indx’ of size 5
>   744 |         u8 lkup_indx[5];
>       |            ^~~~~~~~~
> In function ‘ice_add_sw_recipe’,
>     inlined from ‘ice_add_adv_recipe’
> at ../drivers/net/ice/base/ice_switch.c:7951:11,
>     inlined from ‘ice_add_adv_rule’
> at ../drivers/net/ice/base/ice_switch.c:8911:11:
> ../drivers/net/ice/base/ice_switch.c:7220:61: error: writing 1 byte into a
> region of size 0 [-Werror=stringop-overflow=]
>  7220 |                         buf[recps].content.lkup_indx[i + 1] = entry->fv_idx[i];
>       |
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
> ../drivers/net/ice/base/ice_adminq_cmd.h: In function ‘ice_add_adv_rule’:
> ../drivers/net/ice/base/ice_adminq_cmd.h:744:12: note: at offset [7, 255]
> into destination object ‘lkup_indx’ of size 5
>   744 |         u8 lkup_indx[5];
>       |            ^~~~~~~~~
> cc1: all warnings being treated as errors
> 
> Thanks
> Wenxuan
> 
> > -----Original Message-----
> > From: Zhang, Qi Z <qi.z.zhang@intel.com>
> > Sent: 2022年6月19日 20:35
> > To: Wu, WenxuanX <wenxuanx.wu@intel.com>; Yang, Qiming
> > <qiming.yang@intel.com>; dev@dpdk.org; thomas@monjalon.net
> > Cc: stephen@networkplumber.org; stable@dpdk.org
> > Subject: RE: [PATCH] ice/base: fix gcc 12 warning stringop-overflow
> >
> >
> >
> > > -----Original Message-----
> > > From: Wu, WenxuanX <wenxuanx.wu@intel.com>
> > > Sent: Thursday, June 16, 2022 6:33 PM
> > > To: Yang, Qiming <qiming.yang@intel.com>; Zhang, Qi Z
> > > <qi.z.zhang@intel.com>; dev@dpdk.org; thomas@monjalon.net
> > > Cc: stephen@networkplumber.org; Wu, WenxuanX
> > <wenxuanx.wu@intel.com>;
> > > stable@dpdk.org
> > > Subject: [PATCH] ice/base: fix gcc 12 warning stringop-overflow
> > >
> > > From: Wenxuan Wu <wenxuanx.wu@intel.com>
> > >
> > > Gcc with -O2 flag, would retrieve the value in one time.
> > > This patch changed the type of fv_idx in struct ice_recp_grp_entry
> > > to align with its callers which is also u8 type.
> > >
> > > When u8 idx[5] = a value u16 index[4], gcc12 would give this
> > > warning, because it is not big enough to store the bytes(bigger than
> > > 5 bytes) in one time (-O2 would do it in this way).
> > >
> > > Fixes: 04b8ec1ea807 ("net/ice/base: add protocol structures and
> > > defines")
> > > Cc: stable@dpdk.org
> > > Signed-off-by: Wenxuan Wu <wenxuanx.wu@intel.com>
> > > ---
> > >  drivers/net/ice/base/ice_protocol_type.h | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/ice/base/ice_protocol_type.h
> > > b/drivers/net/ice/base/ice_protocol_type.h
> > > index 0e6e5990be..cfe3b62630 100644
> > > --- a/drivers/net/ice/base/ice_protocol_type.h
> > > +++ b/drivers/net/ice/base/ice_protocol_type.h
> > > @@ -421,7 +421,7 @@ struct ice_recp_grp_entry {  #define
> > > ICE_INVAL_CHAIN_IND 0xFF
> > >  	u16 rid;
> > >  	u8 chain_idx;
> > > -	u16 fv_idx[ICE_NUM_WORDS_RECIPE];
> > > +	u8 fv_idx[ICE_NUM_WORDS_RECIPE];
> >
> > If you change the data type from u16 to u8 for the FV index, you'd
> > better also change the type of all the symbols to store the same
> > thing.  e.g. the parameter "fv_idx" of ice_find_prot_off.
> > So, what's exactly the issue that GCC 12 reported? can we fix it from
> > the other side without changing a type in the base code?
        change from u8 lkup_indx[5] to u16 lkup_indx[5] can also resolve this issue. 
> >
> >
> > >  	u16 fv_mask[ICE_NUM_WORDS_RECIPE];
> > >  	struct ice_pref_recipe_group r_group;  };
> > > --
> > > 2.25.1