[BUG] allmodconfig build error in next-20240108

[Lucas De Marchi]

On Wed, Jan 10, 2024 at 02:26:54AM -0800, Paul E. McKenney wrote:
>On Wed, Jan 10, 2024 at 04:03:51PM +1100, Stephen Rothwell wrote:
>> Hi Paul,
>>
>> On Tue, 9 Jan 2024 19:46:27 -0800 "Paul E. McKenney" <paulmck at kernel.org> wrote:
>> >
>> > On Wed, Jan 10, 2024 at 09:58:22AM +1100, Stephen Rothwell wrote:
>> > >
>> > > Maybe that line "subdir-ccflags-y += $(call cc-option, -Wstringop-overflow)"
>> > > should just be removed as the setting of that option has been moved to the
>> > > normal C flags in the top level Makefile (out of Makefile.extrawarn).
>> >
>> > If you meant like this, no joy.  :-(
>>
>> Actually I meant the one in drivers/gpu/drm/xe/Makefile
>
>Like this?  That does work as shown below, thank you!
>
>							Thanx, Paul
>
>------------------------------------------------------------------------
>
>drm/xe: Fix build bug for GCC 11
>
>Building drivers/gpu/drm/xe/xe_gt_pagefault.c with GCC 11 results
>in the following build errors:
>
>./include/linux/fortify-string.h:57:33: error: writing 16 bytes into a region of size 0 [-Werror=stringop-overflow=]
>   57 | #define __underlying_memcpy     __builtin_memcpy
>      |                                 ^
>./include/linux/fortify-string.h:644:9: note: in expansion of macro ‘__underlying_memcpy’
>  644 |         __underlying_##op(p, q, __fortify_size);                        \
>      |         ^~~~~~~~~~~~~
>./include/linux/fortify-string.h:689:26: note: in expansion of macro ‘__fortify_memcpy_chk’
>  689 | #define memcpy(p, q, s)  __fortify_memcpy_chk(p, q, s,                  \
>      |                          ^~~~~~~~~~~~~~~~~~~~
>drivers/gpu/drm/xe/xe_gt_pagefault.c:340:17: note: in expansion of macro ‘memcpy’
>  340 |                 memcpy(pf_queue->data + pf_queue->tail, msg, len * sizeof(u32));
>      |                 ^~~~~~
>In file included from drivers/gpu/drm/xe/xe_device_types.h:17,
>                 from drivers/gpu/drm/xe/xe_vm_types.h:16,
>                 from drivers/gpu/drm/xe/xe_bo.h:13,
>                 from drivers/gpu/drm/xe/xe_gt_pagefault.c:16:
>drivers/gpu/drm/xe/xe_gt_types.h:102:25: note: at offset [1144, 265324] into destination object ‘tile’ of size 8
>  102 |         struct xe_tile *tile;
>      |                         ^~~~
>
>Fix these by removing -Wstringop-overflow from drm/xe builds.
>
>Suggested-by: Stephen Rothwell <sfr at rothwell.id.au>
>Signed-off-by: Paul E. McKenney <paulmck at kernel.org>

[ This particular warning is broken on GCC11. In future changes it will
   be moved to the normal C flags in the top level Makefile (out of
   Makefile.extrawarn), but accounting for the compiler support. Just
   remove it out of xe's forced extra warnings for now ]
Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>

would you mind if I extend it to drivers/gpu/drm/i915/Makefile
in the same commit or would you prefer a separate one?


Lucas De Marchi

>
>diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
>index 53bd2a8ba1ae..efcf0ab7a1a6 100644
>--- a/drivers/gpu/drm/xe/Makefile
>+++ b/drivers/gpu/drm/xe/Makefile
>@@ -17,7 +17,6 @@ subdir-ccflags-y += $(call cc-option, -Wunused-const-variable)
> subdir-ccflags-y += $(call cc-option, -Wpacked-not-aligned)
> subdir-ccflags-y += $(call cc-option, -Wformat-overflow)
> subdir-ccflags-y += $(call cc-option, -Wformat-truncation)
>-subdir-ccflags-y += $(call cc-option, -Wstringop-overflow)
> subdir-ccflags-y += $(call cc-option, -Wstringop-truncation)
> # The following turn off the warnings enabled by -Wextra
> ifeq ($(findstring 2, $(KBUILD_EXTRA_WARN)),)