Hi Jiri, Kernel build failed on tree: git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git tmp_perf/dwarf head: 48f53d5eb51405488e42c545396fc5308346fd09 commit: 036a086d9690fd049d2685cb299ae41875ef3389 [14/21] perf: Add ability to attach user stack dump to sample config: mips-fuloong2e_defconfig (attached as .config) All related error/warning messages: kernel/events/core.c: In function 'perf_output_sample_ustack': kernel/events/core.c:3818:3: error: implicit declaration of function 'user_stack_pointer' [-Werror=implicit-function-declaration] cc1: some warnings being treated as errors vim +3818 kernel/events/core.c 3815 perf_output_put(handle, dump_size); 3816 3817 /* Data. */ > 3818 sp = user_stack_pointer(regs); 3819 rem = __output_copy_user(handle, (void *) sp, dump_size); 3820 dyn_size = dump_size - rem; 3821 --- 0-DAY kernel build testing backend Open Source Technology Centre Fengguang Wu Intel Corporation