Once CONFIG_KSTACK_ERASE is enabled with Clang on i386, the build warns: kernel/kstack_erase.c:168:2: warning: function with attribute 'no_caller_saved_registers' should only call a function with attribute 'no_caller_saved_registers' or be compiled with '-mgeneral-regs-only' [-Wexcessive-regsave]
Add -mgeneral-regs-only for the kstack_erase handler, to make Clang feel better (it is effectively a no-op flag for the kernel). No binary changes encountered. Build & boot tested with Clang 21 on x86_64, and i386. Build tested with GCC 14.2.0 on x86_64, i386, arm64, and arm. Reported-by: Nathan Chancellor <[email protected]> Closes: https://lore.kernel.org/all/20250726004313.GA3650901@ax162 Signed-off-by: Kees Cook <[email protected]> --- kernel/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/Makefile b/kernel/Makefile index e4f01f1d4d0c..0ee9afd8b7cf 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -140,6 +140,7 @@ obj-$(CONFIG_RESOURCE_KUNIT_TEST) += resource_kunit.o obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o CFLAGS_kstack_erase.o += $(DISABLE_KSTACK_ERASE) +CFLAGS_kstack_erase.o += $(call cc-option,-mgeneral-regs-only) obj-$(CONFIG_KSTACK_ERASE) += kstack_erase.o KASAN_SANITIZE_kstack_erase.o := n KCSAN_SANITIZE_kstack_erase.o := n -- 2.34.1
