6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nathan Chancellor nathan@kernel.org
commit 41f9049cff324b7033e6ed1ded7dfff803cf550a upstream.
When building with CONFIG_CMODEL_MEDLOW and CONFIG_LTO_CLANG, there is a series of errors due to some files being unconditionally compiled with '-mcmodel=medany', mismatching with the rest of the kernel built with '-mcmodel=medlow':
ld.lld: error: Function Import: link error: linking module flags 'Code Model': IDs have conflicting values: 'i32 3' from vmlinux.a(init.o at 899908), and 'i32 1' from vmlinux.a(net-traces.o at 1014628)
Only allow LTO to be performed when CONFIG_CMODEL_MEDANY is enabled to ensure there will be no code model mismatch errors. An alternative solution would be disabling LTO for the files with a different code model than the main kernel like some specialized areas of the kernel do but doing that for individual files is not as sustainable than forbidding the combination altogether.
Cc: stable@vger.kernel.org Fixes: 021d23428bdb ("RISC-V: build: Allow LTO to be selected") Reported-by: kernel test robot lkp@intel.com Closes: https://lore.kernel.org/oe-kbuild-all/202506290255.KBVM83vZ-lkp@intel.com/ Signed-off-by: Nathan Chancellor nathan@kernel.org Link: https://lore.kernel.org/r/20250710-riscv-restrict-lto-to-medany-v1-1-b1dac98... Signed-off-by: Paul Walmsley pjw@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/riscv/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -61,7 +61,7 @@ config RISCV select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU select ARCH_SUPPORTS_HUGETLBFS if MMU # LLD >= 14: https://github.com/llvm/llvm-project/issues/50505 - select ARCH_SUPPORTS_LTO_CLANG if LLD_VERSION >= 140000 + select ARCH_SUPPORTS_LTO_CLANG if LLD_VERSION >= 140000 && CMODEL_MEDANY select ARCH_SUPPORTS_LTO_CLANG_THIN if LLD_VERSION >= 140000 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU select ARCH_SUPPORTS_PER_VMA_LOCK if MMU