Hi Jiri, kernel test robot noticed the following build errors: [auto build test ERROR on bpf/master] url: https://github.com/intel-lab-lkp/linux/commits/Jiri-Olsa/bpf-x64-Fix-prog_array_map_poke_run-map-poke-update/20231127-174900 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git master patch link: https://lore.kernel.org/r/20231127094525.1366740-1-jolsa%40kernel.org patch subject: [PATCH bpf] bpf, x64: Fix prog_array_map_poke_run map poke update config: i386-randconfig-061-20231127 (https://download.01.org/0day-ci/archive/20231127/202311272245.sevnkuSF-lkp@xxxxxxxxx/config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231127/202311272245.sevnkuSF-lkp@xxxxxxxxx/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 <lkp@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202311272245.sevnkuSF-lkp@xxxxxxxxx/ All errors (new ones prefixed by >>): ld: kernel/bpf/arraymap.o: in function `prog_array_map_poke_run': >> kernel/bpf/arraymap.c:1067: undefined reference to `__bpf_arch_text_poke' >> ld: kernel/bpf/arraymap.c:1079: undefined reference to `__bpf_arch_text_poke' ld: kernel/bpf/arraymap.c:1090: undefined reference to `__bpf_arch_text_poke' ld: kernel/bpf/arraymap.c:1072: undefined reference to `__bpf_arch_text_poke' vim +1067 kernel/bpf/arraymap.c 1014 1015 static void prog_array_map_poke_run(struct bpf_map *map, u32 key, 1016 struct bpf_prog *old, 1017 struct bpf_prog *new) 1018 { 1019 u8 *old_addr, *new_addr, *old_bypass_addr; 1020 struct prog_poke_elem *elem; 1021 struct bpf_array_aux *aux; 1022 1023 aux = container_of(map, struct bpf_array, map)->aux; 1024 WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex)); 1025 1026 list_for_each_entry(elem, &aux->poke_progs, list) { 1027 struct bpf_jit_poke_descriptor *poke; 1028 int i, ret; 1029 1030 for (i = 0; i < elem->aux->size_poke_tab; i++) { 1031 poke = &elem->aux->poke_tab[i]; 1032 1033 /* Few things to be aware of: 1034 * 1035 * 1) We can only ever access aux in this context, but 1036 * not aux->prog since it might not be stable yet and 1037 * there could be danger of use after free otherwise. 1038 * 2) Initially when we start tracking aux, the program 1039 * is not JITed yet and also does not have a kallsyms 1040 * entry. We skip these as poke->tailcall_target_stable 1041 * is not active yet. The JIT will do the final fixup 1042 * before setting it stable. The various 1043 * poke->tailcall_target_stable are successively 1044 * activated, so tail call updates can arrive from here 1045 * while JIT is still finishing its final fixup for 1046 * non-activated poke entries. 1047 * 3) Also programs reaching refcount of zero while patching 1048 * is in progress is okay since we're protected under 1049 * poke_mutex and untrack the programs before the JIT 1050 * buffer is freed. 1051 * 4) Any error happening below from __bpf_arch_text_poke() 1052 * is a unexpected bug. 1053 */ 1054 if (!READ_ONCE(poke->tailcall_target_stable)) 1055 continue; 1056 if (poke->reason != BPF_POKE_REASON_TAIL_CALL) 1057 continue; 1058 if (poke->tail_call.map != map || 1059 poke->tail_call.key != key) 1060 continue; 1061 1062 old_bypass_addr = old ? NULL : poke->bypass_addr; 1063 old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL; 1064 new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL; 1065 1066 if (new) { > 1067 ret = __bpf_arch_text_poke(poke->tailcall_target, 1068 BPF_MOD_JUMP, 1069 old_addr, new_addr); 1070 BUG_ON(ret < 0); 1071 if (!old) { 1072 ret = __bpf_arch_text_poke(poke->tailcall_bypass, 1073 BPF_MOD_JUMP, 1074 poke->bypass_addr, 1075 NULL); 1076 BUG_ON(ret < 0); 1077 } 1078 } else { > 1079 ret = __bpf_arch_text_poke(poke->tailcall_bypass, 1080 BPF_MOD_JUMP, 1081 old_bypass_addr, 1082 poke->bypass_addr); 1083 BUG_ON(ret < 0); 1084 /* let other CPUs finish the execution of program 1085 * so that it will not possible to expose them 1086 * to invalid nop, stack unwind, nop state 1087 */ 1088 if (!ret) 1089 synchronize_rcu(); 1090 ret = __bpf_arch_text_poke(poke->tailcall_target, 1091 BPF_MOD_JUMP, 1092 old_addr, NULL); 1093 BUG_ON(ret < 0); 1094 } 1095 } 1096 } 1097 } 1098 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
