Re: [BUG] allmodconfig build error in next-20240108

["Paul E. McKenney" <paulmck@kernel.org>]

On Wed, Jan 10, 2024 at 09:00:06AM -0600, Lucas De Marchi wrote:
> 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@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@rothwell.id.au>
> > Signed-off-by: Paul E. McKenney <paulmck@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@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?

Whatever works best for you works for me!

							Thanx, Paul

> 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)),)