| Message ID | 20241219-amdgpu-dml2-address-clang-frame-larger-than-allconfig-v1-1-8c53a644d486@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | drm/amd/display: Increase sanitizer frame larger than limit when compile testing with clang | expand |
diff --git a/drivers/gpu/drm/amd/display/dc/dml2/Makefile b/drivers/gpu/drm/amd/display/dc/dml2/Makefile index d9c27ebe12ee08d6330eb199cd8ca9c8489fa5b2..91c4f3b4bd5f46ac5c1c74f665b06dbe61081917 100644 --- a/drivers/gpu/drm/amd/display/dc/dml2/Makefile +++ b/drivers/gpu/drm/amd/display/dc/dml2/Makefile @@ -29,7 +29,11 @@ dml2_rcflags := $(CC_FLAGS_NO_FPU) ifneq ($(CONFIG_FRAME_WARN),0) ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y) +ifeq ($(CONFIG_CC_IS_CLANG)$(CONFIG_COMPILE_TEST),yy) +frame_warn_flag := -Wframe-larger-than=4096 +else frame_warn_flag := -Wframe-larger-than=3072 +endif else frame_warn_flag := -Wframe-larger-than=2048 endif
Commit 24909d9ec7c3 ("drm/amd/display: Overwriting dualDPP UBF values before usage") added a new warning in dml2/display_mode_core.c when building allmodconfig with clang: drivers/gpu/drm/amd/amdgpu/../display/dc/dml2/display_mode_core.c:6268:13: error: stack frame size (3128) exceeds limit (3072) in 'dml_prefetch_check' [-Werror,-Wframe-larger-than] 6268 | static void dml_prefetch_check(struct display_mode_lib_st *mode_lib) | ^ Commit be4e3509314a ("drm/amd/display: DML21 Reintegration For Various Fixes") introduced one in dml2_core/dml2_core_dcn4_calcs.c with the same configuration: drivers/gpu/drm/amd/amdgpu/../display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c:7236:13: error: stack frame size (3256) exceeds limit (3072) in 'dml_core_mode_support' [-Werror,-Wframe-larger-than] 7236 | static bool dml_core_mode_support(struct dml2_core_calcs_mode_support_ex *in_out_params) | ^ In the case of the first warning, the stack usage was already at the limit at the parent change, so the offending change was rather innocuous. In the case of the second warning, there was a rather dramatic increase in stack usage compared to the parent: drivers/gpu/drm/amd/amdgpu/../display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c:7032:13: error: stack frame size (2696) exceeds limit (2048) in 'dml_core_mode_support' [-Werror,-Wframe-larger-than] 7032 | static bool dml_core_mode_support(struct dml2_core_calcs_mode_support_ex *in_out_params) | ^ This is an unfortunate interaction between an issue with stack slot reuse in LLVM that gets exacerbated by sanitization (which gets enabled with all{mod,yes}config) and function calls using a much higher number of parameters than is typical in the kernel, necessitating passing most of these values on the stack. While it is possible that there should be source code changes to address these warnings, this code is difficult to modify for various reasons, as has been noted in other changes that have occurred for similar reasons, such as commit 6740ec97bcdb ("drm/amd/display: Increase frame warning limit with KASAN or KCSAN in dml2"). Increase the frame larger than limit when compile testing with clang and the sanitizers enabled to avoid this breakage in all{mod,yes}config, as they are commonly used and valuable testing targets. While it is not the best to hide this issue, it is not really relevant when compile testing, as the sanitizers are commonly stressful on optimizations and they are only truly useful at runtime, which COMPILE_TEST states will not occur with the current build. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202412121748.chuX4sap-lkp@intel.com/ Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- drivers/gpu/drm/amd/display/dc/dml2/Makefile | 4 ++++ 1 file changed, 4 insertions(+) --- base-commit: 695c2c745e5dff201b75da8a1d237ce403600d04 change-id: 20241219-amdgpu-dml2-address-clang-frame-larger-than-allconfig-f034d9c5118e Best regards,