Hi Pingfan, kernel test robot noticed the following build warnings:
[auto build test WARNING on bpf-next/net] [also build test WARNING on bpf-next/master bpf/master akpm-mm/mm-nonmm-unstable linus/master v6.19-rc6 next-20260116] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Pingfan-Liu/bpf-Introduce-kfuncs-to-parser-buffer-content/20260119-112939 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git net patch link: https://lore.kernel.org/r/20260119032424.10781-12-piliu%40redhat.com patch subject: [PATCHv6 11/13] arm64/kexec: Select KEXEC_BPF to support UEFI-style kernel image config: arm64-randconfig-004-20260119 (https://download.01.org/0day-ci/archive/20260119/[email protected]/config) compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260119/[email protected]/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <[email protected]> | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ All warnings (new ones prefixed by >>): >> kernel/kexec_bpf_loader.c:103:22: warning: unknown attribute 'optimize' >> ignored [-Wunknown-attributes] 103 | __attribute__((used, optimize("O0"))) void kexec_image_parser_anchor( | ^~~~~~~~~~~~~~ 1 warning generated. Kconfig warnings: (for reference only) WARNING: unmet direct dependencies detected for KEXEC_BPF Depends on [n]: KEXEC_FILE [=y] && DEBUG_INFO_BTF [=y] && BPF_SYSCALL [=y] && KEEP_DECOMPRESSOR [=n] Selected by [y]: - ARCH_SELECTS_KEXEC_FILE [=y] && KEXEC_FILE [=y] && DEBUG_INFO_BTF [=y] && BPF_SYSCALL [=y] vim +/optimize +103 kernel/kexec_bpf_loader.c e683ae405ea0458 Pingfan Liu 2026-01-19 93 e683ae405ea0458 Pingfan Liu 2026-01-19 94 void kexec_image_parser_anchor(struct kexec_context *context, e683ae405ea0458 Pingfan Liu 2026-01-19 95 unsigned long parser_id); e683ae405ea0458 Pingfan Liu 2026-01-19 96 e683ae405ea0458 Pingfan Liu 2026-01-19 97 /* e683ae405ea0458 Pingfan Liu 2026-01-19 98 * optimize("O0") prevents inline, compiler constant propagation e683ae405ea0458 Pingfan Liu 2026-01-19 99 * e683ae405ea0458 Pingfan Liu 2026-01-19 100 * Let bpf be the program context pointer so that it will not be spilled into e683ae405ea0458 Pingfan Liu 2026-01-19 101 * stack. e683ae405ea0458 Pingfan Liu 2026-01-19 102 */ e683ae405ea0458 Pingfan Liu 2026-01-19 @103 __attribute__((used, optimize("O0"))) void kexec_image_parser_anchor( e683ae405ea0458 Pingfan Liu 2026-01-19 104 struct kexec_context *context, e683ae405ea0458 Pingfan Liu 2026-01-19 105 unsigned long parser_id) e683ae405ea0458 Pingfan Liu 2026-01-19 106 { e683ae405ea0458 Pingfan Liu 2026-01-19 107 /* e683ae405ea0458 Pingfan Liu 2026-01-19 108 * To prevent linker from Identical Code Folding (ICF) with kexec_image_parser_anchor, e683ae405ea0458 Pingfan Liu 2026-01-19 109 * making them have different code. e683ae405ea0458 Pingfan Liu 2026-01-19 110 */ e683ae405ea0458 Pingfan Liu 2026-01-19 111 volatile int dummy = 0; e683ae405ea0458 Pingfan Liu 2026-01-19 112 e683ae405ea0458 Pingfan Liu 2026-01-19 113 dummy += 1; e683ae405ea0458 Pingfan Liu 2026-01-19 114 } e683ae405ea0458 Pingfan Liu 2026-01-19 115 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
