On Thu, Oct 19, 2023 at 02:53:01PM +0200, Arnd Bergmann wrote: > On Thu, Oct 19, 2023, at 12:04, Alexander Potapenko wrote: > > So the remaining option would be to just increase the frame size every > > time a new function surpasses the limit. > > That is clearly not an option, though we could try to > add Kconfig dependencies that avoid the known bad combinations, > such as annotating the AMD GPU driver as > > depends on (CC_IS_GCC || CLANG_VERSION >=180000) || !(KASAN || KCSAN) This would effectively disable the AMDGPU driver for allmodconfig, which is somewhat unfortunate as it is an easy testing target. Taking a step back, this is all being done because of a couple of warnings in the AMDGPU code. If fixing those in the source is too much effort (I did note [1] that GCC is at the current limit for that file even with Rodrigo's series applied [2]), couldn't we just take the existing workaround that this Makefile has for this file and its high stack usage and just extend it slightly for clang? diff --git a/drivers/gpu/drm/amd/display/dc/dml2/Makefile b/drivers/gpu/drm/amd/display/dc/dml2/Makefile index 66431525f2a0..fd49e3526c0d 100644 --- a/drivers/gpu/drm/amd/display/dc/dml2/Makefile +++ b/drivers/gpu/drm/amd/display/dc/dml2/Makefile @@ -58,7 +58,7 @@ endif endif ifneq ($(CONFIG_FRAME_WARN),0) -frame_warn_flag := -Wframe-larger-than=2048 +frame_warn_flag := -Wframe-larger-than=$(if $(CONFIG_CC_IS_CLANG),3072,2048) endif CFLAGS_$(AMDDALPATH)/dc/dml2/display_mode_core.o := $(dml2_ccflags) $(frame_warn_flag) That would address the immediate concern of the warning breaking builds with CONFIG_WERROR=y while not raising the limit for other files in the kernel (just this one file in AMDGPU) and avoiding disabling the whole driver. The number could be lower, I think ~2500 bytes is the most usage I see with Rodrigo's series applied, so maybe 2800 would be a decent limit? Once there is a fix in the compiler, this expression could be changed to use clang-min-version or something of that sort. [1]: https://lore.kernel.org/20231017172231.GA2348194@dev-arch.thelio-3990X/ [2]: https://lore.kernel.org/20231016142031.241912-1-Rodrigo.Siqueira@xxxxxxx/ Cheers, Nathan
