On 12/17/21 7:56 PM, Mauricio Vásquez wrote:
CO-RE requires to have BTF information describing the types of the kernel in order to perform the relocations. This is usually provided by the kernel itself when it's configured with CONFIG_DEBUG_INFO_BTF. However, this configuration is not enabled in all the distributions and it's not available on kernels before 5.12.
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Changelog: v2 > v3: - expose internal libbpf APIs to bpftool instead - implement btfgen in bpftool - drop btf__raw_data() from libbpf
Looks like this breaks bpf-next CI, please take a look: https://github.com/kernel-patches/bpf/runs/4565944884?check_suite_focus=true [...] All error logs: #36 core_kern_lskel:FAIL test_core_kern_lskel:FAIL:open_and_load unexpected error: -22 #69 kfunc_call:FAIL test_main:PASS:skel 0 nsec test_main:PASS:bpf_prog_test_run(test1) 0 nsec test_main:PASS:test1-retval 0 nsec test_main:PASS:bpf_prog_test_run(test2) 0 nsec test_main:PASS:test2-retval 0 nsec #69/1 kfunc_call/main:OK test_subprog:PASS:skel 0 nsec test_subprog:PASS:bpf_prog_test_run(test1) 0 nsec test_subprog:PASS:test1-retval 0 nsec test_subprog:PASS:active_res 0 nsec test_subprog:PASS:sk_state_res 0 nsec #69/2 kfunc_call/subprog:OK test_subprog_lskel:FAIL:skel unexpected error: -22 #69/3 kfunc_call/subprog_lskel:FAIL #71 ksyms_btf:FAIL test_ksyms_btf:PASS:btf_exists 0 nsec test_basic:PASS:kallsyms_fopen 0 nsec test_basic:PASS:ksym_find 0 nsec test_basic:PASS:kallsyms_fopen 0 nsec test_basic:PASS:ksym_find 0 nsec test_basic:PASS:skel_open 0 nsec test_basic:PASS:skel_attach 0 nsec test_basic:PASS:runqueues_addr 0 nsec test_basic:PASS:bpf_prog_active_addr 0 nsec test_basic:PASS:rq_cpu 0 nsec test_basic:PASS:bpf_prog_active 0 nsec test_basic:PASS:cpu_rq(0)->cpu 0 nsec test_basic:PASS:this_rq_cpu 0 nsec test_basic:PASS:this_bpf_prog_active 0 nsec #71/1 ksyms_btf/basic:OK libbpf: prog 'handler': BPF program load failed: Permission denied libbpf: prog 'handler': -- BEGIN PROG LOAD LOG -- arg#0 reference type('UNKNOWN ') size cannot be determined: -22 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 ; cpu = bpf_get_smp_processor_id(); 0: (85) call bpf_get_smp_processor_id#8 ; R0_w=inv(id=0) 1: (bc) w7 = w0 ; R0_w=inv(id=0) R7_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) ; rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, cpu); 2: (18) r1 = 0x2bd80 ; R1_w=percpu_ptr_rq(id=0,off=0,imm=0) 4: (bc) w2 = w7 ; R2_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R7_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) 5: (85) call bpf_per_cpu_ptr#153 ; R0_w=ptr_or_null_rq(id=1,off=0,imm=0) 6: (bf) r6 = r0 ; R0_w=ptr_or_null_rq(id=1,off=0,imm=0) R6_w=ptr_or_null_rq(id=1,off=0,imm=0) ; active = (int *)bpf_per_cpu_ptr(&bpf_prog_active, cpu); 7: (18) r1 = 0x27de0 ; R1_w=percpu_ptr_int(id=0,off=0,imm=0) 9: (bc) w2 = w7 ; R2_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R7_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) 10: (85) call bpf_per_cpu_ptr#153 ; R0=mem_or_null(id=2,ref_obj_id=0,off=0,imm=0) ; if (active) { 11: (15) if r0 == 0x0 goto pc+2 ; R0=mem(id=0,ref_obj_id=0,off=0,imm=0) ; *(volatile int *)active; 12: (61) r1 = *(u32 *)(r0 +0) ; R0=mem(id=0,ref_obj_id=0,off=0,imm=0) R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) ; *(volatile int *)(&rq->cpu); 13: (61) r1 = *(u32 *)(r6 +2848) R6 invalid mem access 'ptr_or_null_' processed 12 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 1 -- END PROG LOAD LOG -- libbpf: failed to load program 'handler' libbpf: failed to load object 'test_ksyms_btf_null_check' libbpf: failed to load BPF skeleton 'test_ksyms_btf_null_check': -13 test_null_check:PASS:skel_open 0 nsec #71/2 ksyms_btf/null_check:OK test_weak_syms:PASS:test_ksyms_weak__open_and_load 0 nsec test_weak_syms:PASS:test_ksyms_weak__attach 0 nsec test_weak_syms:PASS:existing typed ksym 0 nsec test_weak_syms:PASS:existing typeless ksym 0 nsec test_weak_syms:PASS:nonexistent typeless ksym 0 nsec test_weak_syms:PASS:nonexistent typed ksym 0 nsec #71/3 ksyms_btf/weak_ksyms:OK test_weak_syms_lskel:FAIL:test_ksyms_weak_lskel__open_and_load unexpected error: -22 #71/4 ksyms_btf/weak_ksyms_lskel:FAIL #89 map_ptr:FAIL test_map_ptr:PASS:skel_open 0 nsec test_map_ptr:FAIL:skel_load unexpected error: -22 (errno 22) Summary: 221/1052 PASSED, 8 SKIPPED, 4 FAILED test_progs-no_alu32 - Testing test_progs-no_alu32 test_maps - Testing test_maps test_verifier - Testing test_verifier collect_status - Collect status shutdown - Shutdown Test Results: bpftool: PASS test_progs: FAIL (returned 1) test_progs-no_alu32: FAIL (returned 1) test_maps: PASS test_verifier: PASS shutdown: CLEAN Error: Process completed with exit code 1.
v1 > v2: - introduce bpf_object__prepare() and ‘record_core_relos’ to expose CO-RE relocations instead of bpf_object__reloc_info_gen() - rename btf__save_to_file() to btf__raw_data() v1: https://lore.kernel.org/bpf/20211027203727.208847-1-mauricio@xxxxxxxxxx/ v2: https://lore.kernel.org/bpf/20211116164208.164245-1-mauricio@xxxxxxxxxx/ Mauricio Vásquez (3): libbpf: split bpf_core_apply_relo() libbpf: Implement changes needed for BTFGen in bpftool bpftool: Implement btfgen kernel/bpf/btf.c | 11 +- tools/bpf/bpftool/gen.c | 892 ++++++++++++++++++++++++++++++++ tools/lib/bpf/Makefile | 2 +- tools/lib/bpf/libbpf.c | 124 +++-- tools/lib/bpf/libbpf.h | 3 + tools/lib/bpf/libbpf.map | 2 + tools/lib/bpf/libbpf_internal.h | 22 + tools/lib/bpf/relo_core.c | 83 +-- tools/lib/bpf/relo_core.h | 46 +- 9 files changed, 1086 insertions(+), 99 deletions(-)
