Re: [dpdk-stable] [PATCH v3 3/4] net/ice/base: fix build with gcc11

["Wang, Haiyue" <haiyue.wang@intel.com>]

> -----Original Message-----
> From: stable <stable-bounces@dpdk.org> On Behalf Of Ferruh Yigit
> Sent: Tuesday, May 11, 2021 21:15
> To: Yang, Qiming <qiming.yang@intel.com>; Zhang, Qi Z <qi.z.zhang@intel.com>; Stillwell Jr, Paul M
> <paul.m.stillwell.jr@intel.com>; Lu, Wenzhuo <wenzhuo.lu@intel.com>; Shukla, Shivanshu
> <shivanshu.shukla@intel.com>; Rong, Leyi <leyi.rong@intel.com>
> Cc: Yigit, Ferruh <ferruh.yigit@intel.com>; dev@dpdk.org; stable@dpdk.org; Kevin Traynor
> <ktraynor@redhat.com>; Ajit Khaparde <ajit.khaparde@broadcom.com>
> Subject: [dpdk-stable] [PATCH v3 3/4] net/ice/base: fix build with gcc11
> 
> Reproduced with '--buildtype=debugoptimized' config,
> compiler version: gcc (GCC) 12.0.0 20210509 (experimental)
> 
> There are multiple build errors, like:
> ../drivers/net/ice/base/ice_switch.c: In function ‘ice_add_marker_act’:
> ../drivers/net/ice/base/ice_switch.c:3727:15:
> 	warning: array subscript ‘struct ice_aqc_sw_rules_elem[0]’
> 	is partly outside array bounds of ‘unsigned char[52]’
> 	[-Warray-bounds]
>  3727 |         lg_act->type = CPU_TO_LE16(ICE_AQC_SW_RULES_T_LG_ACT);
>       |               ^~
> In file included from ../drivers/net/ice/base/ice_type.h:52,
>                  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_osdep.h:209:29:
> 	note: referencing an object of size 52 allocated by ‘rte_zmalloc’
>   209 | #define ice_malloc(h, s)    rte_zmalloc(NULL, s, 0)
>       |                             ^~~~~~~~~~~~~~~~~~~~~~~
> ../drivers/net/ice/base/ice_switch.c:3720:50:
> 	note: in expansion of macro ‘ice_malloc’
>   lg_act = (struct ice_aqc_sw_rules_elem *)ice_malloc(hw, rules_size);
> 
> These errors are mainly because allocated memory is cast to
> "struct ice_aqc_sw_rules_elem *" but allocated size is less than the size
> of "struct ice_aqc_sw_rules_elem".
> 
> "struct ice_aqc_sw_rules_elem" has multiple other structs has unions,
> based on which one is used allocated memory being less than the size of
> "struct ice_aqc_sw_rules_elem" is logically correct but compiler is
> complaining about it.
> 
> Since the allocation is done explicitly and both producer and consumer
> are internal, safe to ignore the warnings. Also to prevent any side
> affect disabling the compiler warning for now, until proper fix done.
> 
> Reducing the warning disable to gcc >= 11 version.
> 
> Bugzilla ID: 678
> Fixes: c7dd15931183 ("net/ice/base: add virtual switch code")
> Fixes: 02acdce2f553 ("net/ice/base: add MAC filter with marker and counter")
> Fixes: f89aa3affa9e ("net/ice/base: support removing advanced rule")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
> Cc: paul.m.stillwell.jr@intel.com
> Cc: qi.z.zhang@intel.com
> Cc: leyi.rong@intel.com
> Cc: Kevin Traynor <ktraynor@redhat.com>
> Cc: Ajit Khaparde <ajit.khaparde@broadcom.com>
> 
> v2:
> * Kevin reported more occurrences, the concern is to have more as the
>   gcc version updated. And as the size of changes increases, the risk of
>   unexpected side affect also increases.
>   So disabling the 'array-bounds' warning for this release for
>   gcc >= 11.0.0.
> ---
>  drivers/net/ice/base/meson.build | 5 +++++
>  1 file changed, 5 insertions(+)
> 

Acked-by: Haiyue Wang <haiyue.wang@intel.com>


And finally, we need to fix the code as: 
https://patchwork.ozlabs.org/project/intel-wired-lan/patch/20210413190345.GA304933@embeddedor/
 "By the way, we are about to be able to globally enable -Warray-bounds and,
 this is one of the last out-of-bounds warnings in linux-next."

> diff --git a/drivers/net/ice/base/meson.build b/drivers/net/ice/base/meson.build
> index 6c548a99775c..3305e5dd1822 100644
> --- a/drivers/net/ice/base/meson.build
> +++ b/drivers/net/ice/base/meson.build
> @@ -23,6 +23,11 @@ error_cflags = [
>          '-Wno-unused-parameter',
>  ]
> 
> +# Bugzilla ID: 678
> +if (toolchain == 'gcc' and cc.version().version_compare('>=11.0.0'))
> +    error_cflags += ['-Wno-array-bounds']
> +endif
> +
>  if is_windows and cc.get_id() != 'clang'
>      cflags += ['-fno-asynchronous-unwind-tables']
>  endif
> --
> 2.31.1