After an innocuous optimization change in clang-22, allmodconfig (which enables CONFIG_KASAN and CONFIG_WERROR) breaks with:
drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn32/display_mode_vba_32.c:1724:6: error: stack frame size (3144) exceeds limit (3072) in 'dml32_ModeSupportAndSystemConfigurationFull' [-Werror,-Wframe-larger-than] 1724 | void dml32_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_lib) | ^
With clang-21, this function was already pretty close to the existing limit of 3072 bytes.
drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn32/display_mode_vba_32.c:1724:6: error: stack frame size (2904) exceeds limit (2048) in 'dml32_ModeSupportAndSystemConfigurationFull' [-Werror,-Wframe-larger-than] 1724 | void dml32_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_lib) | ^
A similar situation occurred in dml2, which was resolved by commit e4479aecf658 ("drm/amd/display: Increase sanitizer frame larger than limit when compile testing with clang") by increasing the limit for clang when compile testing with certain sanitizer enabled, so that allmodconfig (an easy testing target) continues to work.
Apply that same change to the dml folder to clear up the warning for allmodconfig, unbreaking the build.
Cc: stable@vger.kernel.org Closes: https://github.com/ClangBuiltLinux/linux/issues/2135 Signed-off-by: Nathan Chancellor nathan@kernel.org --- drivers/gpu/drm/amd/display/dc/dml/Makefile | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile index b357683b4255..268b5fbdb48b 100644 --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile @@ -30,7 +30,11 @@ dml_rcflags := $(CC_FLAGS_NO_FPU)
ifneq ($(CONFIG_FRAME_WARN),0) ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y) - frame_warn_limit := 3072 + ifeq ($(CONFIG_CC_IS_CLANG)$(CONFIG_COMPILE_TEST),yy) + frame_warn_limit := 4096 + else + frame_warn_limit := 3072 + endif else frame_warn_limit := 2048 endif
--- base-commit: f24e96d69f5b9eb0f3b9c49e53c385c50729edfd change-id: 20251213-dml-bump-frame-warn-clang-sanitizers-0a34fc916aec
Best regards, -- Nathan Chancellor nathan@kernel.org