[PATCH net-next] eth: ice: silence the GCC 12 array-bounds warning

[PATCH net-next] eth: ice: silence the GCC 12 array-bounds warning

[Jakub Kicinski]

GCC 12 gets upset because driver allocates partial
struct ice_aqc_sw_rules_elem buffers. The writes are
within bounds.

Silence these warnings for now, our build bot runs GCC 12
so we won't allow any new instances.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: jesse.brandeburg@intel.com
CC: anthony.l.nguyen@intel.com
---
 drivers/net/ethernet/intel/ice/Makefile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/intel/ice/Makefile b/drivers/net/ethernet/intel/ice/Makefile
index 9183d480b70b..588b6e8c7920 100644
--- a/drivers/net/ethernet/intel/ice/Makefile
+++ b/drivers/net/ethernet/intel/ice/Makefile
@@ -47,3 +47,8 @@ ice-$(CONFIG_DCB) += ice_dcb.o ice_dcb_nl.o ice_dcb_lib.o
 ice-$(CONFIG_RFS_ACCEL) += ice_arfs.o
 ice-$(CONFIG_XDP_SOCKETS) += ice_xsk.o
 ice-$(CONFIG_ICE_SWITCHDEV) += ice_eswitch.o
+
+# FIXME: temporarily silence -Warray-bounds on non W=1 builds
+ifndef KBUILD_EXTRA_WARN
+CFLAGS_ice_switch.o += $(call cc-disable-warning, array-bounds)
+endif
-- 
2.34.3

RE: [PATCH net-next] eth: ice: silence the GCC 12 array-bounds warning

[David Laight]

From: Jakub Kicinski
> Sent: 20 May 2022 07:09
> 
> GCC 12 gets upset because driver allocates partial
> struct ice_aqc_sw_rules_elem buffers. The writes are
> within bounds.
> 
> Silence these warnings for now, our build bot runs GCC 12
> so we won't allow any new instances.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> CC: jesse.brandeburg@intel.com
> CC: anthony.l.nguyen@intel.com
> ---
>  drivers/net/ethernet/intel/ice/Makefile | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/Makefile b/drivers/net/ethernet/intel/ice/Makefile
> index 9183d480b70b..588b6e8c7920 100644
> --- a/drivers/net/ethernet/intel/ice/Makefile
> +++ b/drivers/net/ethernet/intel/ice/Makefile
> @@ -47,3 +47,8 @@ ice-$(CONFIG_DCB) += ice_dcb.o ice_dcb_nl.o ice_dcb_lib.o
>  ice-$(CONFIG_RFS_ACCEL) += ice_arfs.o
>  ice-$(CONFIG_XDP_SOCKETS) += ice_xsk.o
>  ice-$(CONFIG_ICE_SWITCHDEV) += ice_eswitch.o
> +
> +# FIXME: temporarily silence -Warray-bounds on non W=1 builds
> +ifndef KBUILD_EXTRA_WARN
> +CFLAGS_ice_switch.o += $(call cc-disable-warning, array-bounds)
> +endif
> --
> 2.34.3

Is it possible to just add:

CFLAGS_ice_switch.o += $(disable-Warray-bounds)

and then ensure that disable-Warray-bounds is defined
(and expanded) by the time it is actually expanded?
This might be before or after the makefile is expanded.
But it would mean that the work is only done once.
I've an idea that 'call cc-disable-warning' is non-trivial.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

Re: [PATCH net-next] eth: ice: silence the GCC 12 array-bounds warning

[Jakub Kicinski]

On Fri, 20 May 2022 12:58:35 +0000 David Laight wrote:
> > +# FIXME: temporarily silence -Warray-bounds on non W=1 builds
> > +ifndef KBUILD_EXTRA_WARN
> > +CFLAGS_ice_switch.o += $(call cc-disable-warning, array-bounds)
> > +endif
> > --
> > 2.34.3  
> 
> Is it possible to just add:
> 
> CFLAGS_ice_switch.o += $(disable-Warray-bounds)
> 
> and then ensure that disable-Warray-bounds is defined
> (and expanded) by the time it is actually expanded?
> This might be before or after the makefile is expanded.
> But it would mean that the work is only done once.
> I've an idea that 'call cc-disable-warning' is non-trivial.

Happy to do whatever's recommended but the $(disable-Warray-bounds)
does not work, I still see the warning.