Chimera Linux notes that CONFIG_CC_HAS_SANE_STACKPROTECTOR cannot be enabled when cross compiling an x86_64 kernel with clang, even though it does work when natively compiling. When building on aarch64: $ make -sj"$(nproc)" ARCH=x86_64 LLVM=1 defconfig $ grep STACKPROTECTOR .config When building on x86_64: $ make -sj"$(nproc)" ARCH=x86_64 LLVM=1 defconfig $ grep STACKPROTECTOR .config CONFIG_CC_HAS_SANE_STACKPROTECTOR=y CONFIG_HAVE_STACKPROTECTOR=y CONFIG_STACKPROTECTOR=y CONFIG_STACKPROTECTOR_STRONG=y When clang is invoked without a '--target' flag, code is generated for the default target, which is usually the host (it is configurable via cmake). As a result, the has-stack-protector scripts will generate code for the default target but check for x86 specific segment registers, which cannot succeed if the default target is not x86. $(CLANG_FLAGS) contains an explicit '--target' flag so pass that variable along to the has-stack-protector scripts so that the stack protector can be enabled when cross compiling with clang. The 32-bit stack protector cannot currently be enabled with clang, as it does not support '-mstack-protector-guard-symbol', so this results in no functional change for ARCH=i386 when cross compiling. Link: https://github.com/chimera-linux/cports/commit/0fb7e506d5f83fdf2104feb22cdac34934561226 Link: https://github.com/llvm/llvm-project/issues/48553 Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx> --- Fixes: 2a61f4747eea ("stack-protector: test compiler capability in Kconfig and drop AUTO mode") might be appropriate; I am conflicted on fixes tags for problems that that arise due to use cases that were not considered at the time of a change, as it feels wrong to blame the commit for not looking far enough into the future where it might be common for people to have workstations running another architecture other than x86_64. Chimera appears to use a 5.15 kernel so a Cc: stable@xxxxxxxxxxxxxxx might be nice but some maintainers are picky about that so I leave it up to you all. arch/x86/Kconfig | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index be0b95e51df6..076adde7ead9 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -391,8 +391,8 @@ config PGTABLE_LEVELS config CC_HAS_SANE_STACKPROTECTOR bool - default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT - default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) + default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT + default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) help We have to make sure stack protector is unconditionally disabled if the compiler produces broken code or if it does not let us control base-commit: b13baccc3850ca8b8cccbf8ed9912dbaa0fdf7f3 -- 2.36.1
