tree: https://github.com/intel/linux-intel-lts.git 5.10/preempt-rt head: 92cafac7cc9c1af94b9b5b61e35fbbd39d4f5854 commit: 3b8deb1004dc560a0c356bd2a8fe75e9a557c067 [2/3] Merge tag 'sandbox-lts-v5.10.65-yocto-211007T223057Z' into lts2020/preempt-rt config: um-x86_64_defconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/intel/linux-intel-lts/commit/3b8deb1004dc560a0c356bd2a... git remote add intel-lts https://github.com/intel/linux-intel-lts.git git fetch --no-tags intel-lts 5.10/preempt-rt git checkout 3b8deb1004dc560a0c356bd2a8fe75e9a557c067 # save the attached .config to linux build tree make W=1 ARCH=um SUBARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; Note: the intel-lts/5.10/preempt-rt HEAD 92cafac7cc9c1af94b9b5b61e35fbbd39d4f5854 builds fine. It only hurts bisectability. All errors (new ones prefixed by >>): cc1: warning: arch/um/include/uapi: No such file or directory [-Wmissing-include-dirs] 54 | .lock = INIT_LOCAL_LOCK(lock), | ^~~~~~~~~~~~~~~ 54 | .lock = INIT_LOCAL_LOCK(lock), | ^~~~ | sock cc1: some warnings being treated as errors -- cc1: warning: arch/um/include/uapi: No such file or directory [-Wmissing-include-dirs] 394 | .l = INIT_LOCAL_LOCK(l), | ^~~~~~~~~~~~~~~ 394 | .l = INIT_LOCAL_LOCK(l), | ^ mm/page_alloc.c:2631:5: warning: no previous prototype for 'find_suitable_fallback' [-Wmissing-prototypes] 2631 | int find_suitable_fallback(struct free_area *area, unsigned int order, | ^~~~~~~~~~~~~~~~~~~~~~ mm/page_alloc.c:3633:15: warning: no previous prototype for 'should_fail_alloc_page' [-Wmissing-prototypes] 3633 | noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) | ^~~~~~~~~~~~~~~~~~~~~~ mm/page_alloc.c:6340:20: warning: no previous prototype for 'memmap_init' [-Wmissing-prototypes] 6340 | void __init __weak memmap_init(void) | ^~~~~~~~~~~ mm/page_alloc.c:6378:23: warning: no previous prototype for 'arch_memmap_init' [-Wmissing-prototypes] 6378 | void __meminit __weak arch_memmap_init(unsigned long size, int nid, | ^~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors -- cc1: warning: arch/um/include/uapi: No such file or directory [-Wmissing-include-dirs] 61 | .lock = INIT_LOCAL_LOCK(lock), | ^~~~~~~~~~~~~~~ 61 | .lock = INIT_LOCAL_LOCK(lock), | ^~~~ | sock lib/radix-tree.c:288:6: warning: no previous prototype for 'radix_tree_node_rcu_free' [-Wmissing-prototypes] 288 | void radix_tree_node_rcu_free(struct rcu_head *head) | ^~~~~~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +/INIT_LOCAL_LOCK +54 mm/swap.c ^1da177e4c3f41 Linus Torvalds 2005-04-16 47 b01b2141999936 Ingo Molnar 2020-05-27 48 /* Protecting only lru_rotate.pvec which requires disabling interrupts */ b01b2141999936 Ingo Molnar 2020-05-27 49 struct lru_rotate { b01b2141999936 Ingo Molnar 2020-05-27 50 local_lock_t lock; b01b2141999936 Ingo Molnar 2020-05-27 51 struct pagevec pvec; b01b2141999936 Ingo Molnar 2020-05-27 52 }; b01b2141999936 Ingo Molnar 2020-05-27 53 static DEFINE_PER_CPU(struct lru_rotate, lru_rotate) = { b01b2141999936 Ingo Molnar 2020-05-27 @54 .lock = INIT_LOCAL_LOCK(lock), b01b2141999936 Ingo Molnar 2020-05-27 55 }; b01b2141999936 Ingo Molnar 2020-05-27 56 :::::: The code at line 54 was first introduced by commit :::::: b01b2141999936ac3e4746b7f76c0f204ae4b445 mm/swap: Use local_lock for protection :::::: TO: Ingo Molnar <mingo(a)kernel.org&gt; :::::: CC: Ingo Molnar <mingo(a)kernel.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org