Hi "Toke, I love your patch! Perhaps something to improve:
[auto build test WARNING on net-next/master] [also build test WARNING on vhost/linux-next ipvs/master v5.8-rc5 next-20200713] [cannot apply to bpf-next/master bpf/master net/master] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Toke-H-iland-J-rgensen/bpf-Support-multi-attach-for-freplace-programs/20200714-041410 base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 528ae84a34ffd40da5d3fbff740d28d6dc2c8f8a config: x86_64-allyesconfig (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 02946de3802d3bc65bc9f2eb9b8d4969b5a7add8) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <l...@intel.com> All warnings (new ones prefixed by >>): >> kernel/bpf/verifier.c:10876:7: warning: variable 'addr' is used >> uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] if (ret) ^~~ kernel/bpf/verifier.c:10923:14: note: uninitialized use occurs here *tgt_addr = addr; ^~~~ kernel/bpf/verifier.c:10876:3: note: remove the 'if' if its condition is always true if (ret) ^~~~~~~~ kernel/bpf/verifier.c:10861:7: warning: variable 'addr' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] if (!btf_type_is_func_proto(t)) ^~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/bpf/verifier.c:10923:14: note: uninitialized use occurs here *tgt_addr = addr; ^~~~ kernel/bpf/verifier.c:10861:3: note: remove the 'if' if its condition is always true if (!btf_type_is_func_proto(t)) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/bpf/verifier.c:10750:11: note: initialize the variable 'addr' to silence this warning long addr; ^ = 0 2 warnings generated. vim +10876 kernel/bpf/verifier.c 10733 10734 int bpf_check_attach_target(struct bpf_verifier_log *log, 10735 const struct bpf_prog *prog, 10736 const struct bpf_prog *tgt_prog, 10737 u32 btf_id, 10738 struct btf_func_model *fmodel, 10739 long *tgt_addr, 10740 const char **tgt_name, 10741 const struct btf_type **tgt_type) 10742 { 10743 bool prog_extension = prog->type == BPF_PROG_TYPE_EXT; 10744 const char prefix[] = "btf_trace_"; 10745 int ret = 0, subprog = -1, i; 10746 const struct btf_type *t; 10747 bool conservative = true; 10748 const char *tname; 10749 struct btf *btf; 10750 long addr; 10751 10752 if (!btf_id) { 10753 bpf_log(log, "Tracing programs must provide btf_id\n"); 10754 return -EINVAL; 10755 } 10756 btf = bpf_prog_get_target_btf(prog); 10757 if (!btf) { 10758 bpf_log(log, 10759 "FENTRY/FEXIT program can only be attached to another program annotated with BTF\n"); 10760 return -EINVAL; 10761 } 10762 t = btf_type_by_id(btf, btf_id); 10763 if (!t) { 10764 bpf_log(log, "attach_btf_id %u is invalid\n", btf_id); 10765 return -EINVAL; 10766 } 10767 tname = btf_name_by_offset(btf, t->name_off); 10768 if (!tname) { 10769 bpf_log(log, "attach_btf_id %u doesn't have a name\n", btf_id); 10770 return -EINVAL; 10771 } 10772 if (tgt_prog) { 10773 struct bpf_prog_aux *aux = tgt_prog->aux; 10774 10775 for (i = 0; i < aux->func_info_cnt; i++) 10776 if (aux->func_info[i].type_id == btf_id) { 10777 subprog = i; 10778 break; 10779 } 10780 if (subprog == -1) { 10781 bpf_log(log, "Subprog %s doesn't exist\n", tname); 10782 return -EINVAL; 10783 } 10784 conservative = aux->func_info_aux[subprog].unreliable; 10785 if (prog_extension) { 10786 if (conservative) { 10787 bpf_log(log, 10788 "Cannot replace static functions\n"); 10789 return -EINVAL; 10790 } 10791 if (!prog->jit_requested) { 10792 bpf_log(log, 10793 "Extension programs should be JITed\n"); 10794 return -EINVAL; 10795 } 10796 } 10797 if (!tgt_prog->jited) { 10798 bpf_log(log, "Can attach to only JITed progs\n"); 10799 return -EINVAL; 10800 } 10801 if (tgt_prog->type == prog->type) { 10802 /* Cannot fentry/fexit another fentry/fexit program. 10803 * Cannot attach program extension to another extension. 10804 * It's ok to attach fentry/fexit to extension program. 10805 */ 10806 bpf_log(log, "Cannot recursively attach\n"); 10807 return -EINVAL; 10808 } 10809 if (tgt_prog->type == BPF_PROG_TYPE_TRACING && 10810 prog_extension && 10811 (tgt_prog->expected_attach_type == BPF_TRACE_FENTRY || 10812 tgt_prog->expected_attach_type == BPF_TRACE_FEXIT)) { 10813 /* Program extensions can extend all program types 10814 * except fentry/fexit. The reason is the following. 10815 * The fentry/fexit programs are used for performance 10816 * analysis, stats and can be attached to any program 10817 * type except themselves. When extension program is 10818 * replacing XDP function it is necessary to allow 10819 * performance analysis of all functions. Both original 10820 * XDP program and its program extension. Hence 10821 * attaching fentry/fexit to BPF_PROG_TYPE_EXT is 10822 * allowed. If extending of fentry/fexit was allowed it 10823 * would be possible to create long call chain 10824 * fentry->extension->fentry->extension beyond 10825 * reasonable stack size. Hence extending fentry is not 10826 * allowed. 10827 */ 10828 bpf_log(log, "Cannot extend fentry/fexit\n"); 10829 return -EINVAL; 10830 } 10831 } else { 10832 if (prog_extension) { 10833 bpf_log(log, "Cannot replace kernel functions\n"); 10834 return -EINVAL; 10835 } 10836 } 10837 10838 switch (prog->expected_attach_type) { 10839 case BPF_TRACE_RAW_TP: 10840 if (tgt_prog) { 10841 bpf_log(log, 10842 "Only FENTRY/FEXIT progs are attachable to another BPF prog\n"); 10843 return -EINVAL; 10844 } 10845 if (!btf_type_is_typedef(t)) { 10846 bpf_log(log, "attach_btf_id %u is not a typedef\n", 10847 btf_id); 10848 return -EINVAL; 10849 } 10850 if (strncmp(prefix, tname, sizeof(prefix) - 1)) { 10851 bpf_log(log, "attach_btf_id %u points to wrong type name %s\n", 10852 btf_id, tname); 10853 return -EINVAL; 10854 } 10855 tname += sizeof(prefix) - 1; 10856 t = btf_type_by_id(btf, t->type); 10857 if (!btf_type_is_ptr(t)) 10858 /* should never happen in valid vmlinux build */ 10859 return -EINVAL; 10860 t = btf_type_by_id(btf, t->type); 10861 if (!btf_type_is_func_proto(t)) 10862 /* should never happen in valid vmlinux build */ 10863 return -EINVAL; 10864 10865 break; 10866 case BPF_TRACE_ITER: 10867 if (!btf_type_is_func(t)) { 10868 bpf_log(log, "attach_btf_id %u is not a function\n", 10869 btf_id); 10870 return -EINVAL; 10871 } 10872 t = btf_type_by_id(btf, t->type); 10873 if (!btf_type_is_func_proto(t)) 10874 return -EINVAL; 10875 ret = btf_distill_func_proto(log, btf, t, tname, fmodel); 10876 if (ret) 10877 return ret; 10878 break; 10879 default: 10880 if (!prog_extension) 10881 return -EINVAL; 10882 /* fallthrough */ 10883 case BPF_MODIFY_RETURN: 10884 case BPF_LSM_MAC: 10885 case BPF_TRACE_FENTRY: 10886 case BPF_TRACE_FEXIT: 10887 if (!btf_type_is_func(t)) { 10888 bpf_log(log, "attach_btf_id %u is not a function\n", 10889 btf_id); 10890 return -EINVAL; 10891 } 10892 if (prog_extension && 10893 btf_check_type_match(log, prog, btf, t)) 10894 return -EINVAL; 10895 t = btf_type_by_id(btf, t->type); 10896 if (!btf_type_is_func_proto(t)) 10897 return -EINVAL; 10898 10899 if (tgt_prog && conservative) 10900 t = NULL; 10901 10902 ret = btf_distill_func_proto(log, btf, t, tname, fmodel); 10903 if (ret < 0) 10904 return ret; 10905 10906 if (tgt_prog) { 10907 if (subprog == 0) 10908 addr = (long) tgt_prog->bpf_func; 10909 else 10910 addr = (long) tgt_prog->aux->func[subprog]->bpf_func; 10911 } else { 10912 addr = kallsyms_lookup_name(tname); 10913 if (!addr) { 10914 bpf_log(log, 10915 "The address of function %s cannot be found\n", 10916 tname); 10917 return -ENOENT; 10918 } 10919 } 10920 break; 10921 } 10922 10923 *tgt_addr = addr; 10924 if (tgt_name) 10925 *tgt_name = tname; 10926 if (tgt_type) 10927 *tgt_type = t; 10928 return 0; 10929 } 10930 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org
.config.gz
Description: application/gzip
