On Tue, Feb 18, 2025 at 2:51 PM Eduard Zingerman <eddyz87@xxxxxxxxx> wrote: > > On Mon, 2025-02-17 at 13:21 +0800, Tao Chen wrote: > > 在 2025/2/12 23:39, Tao Chen 写道: > > > More and more kfunc functions are being added to the kernel. > > > Different prog types have different restrictions when using kfunc. > > > Therefore, prog_kfunc probe is added to check whether it is supported, > > > and the use of this api will be added to bpftool later. > > > > > > Change list: > > > - v6 -> v7: > > > - wrap err with libbpf_err > > > - comments fix > > > - handle btf_fd < 0 as vmlinux > > > - patchset Reviewed-by: Jiri Olsa <jolsa@xxxxxxxxxx> > > > - v6 > > > https://lore.kernel.org/bpf/20250211111859.6029-1-chen.dylane@xxxxxxxxx > > > > > > - v5 -> v6: > > > - remove fd_array_cnt > > > - test case clean code > > > - v5 > > > https://lore.kernel.org/bpf/20250210055945.27192-1-chen.dylane@xxxxxxxxx > > > > > > - v4 -> v5: > > > - use fd_array on stack > > > - declare the scope of use of btf_fd > > > - v4 > > > https://lore.kernel.org/bpf/20250206051557.27913-1-chen.dylane@xxxxxxxxx/ > > > > > > - v3 -> v4: > > > - add fd_array init for kfunc in mod btf > > > - add test case for kfunc in mod btf > > > - refactor common part as prog load type check for > > > libbpf_probe_bpf_{helper,kfunc} > > > - v3 > > > https://lore.kernel.org/bpf/20250124144411.13468-1-chen.dylane@xxxxxxxxx > > > > > > - v2 -> v3: > > > - rename parameter off with btf_fd > > > - extract the common part for libbpf_probe_bpf_{helper,kfunc} > > > - v2 > > > https://lore.kernel.org/bpf/20250123170555.291896-1-chen.dylane@xxxxxxxxx > > > > > > - v1 -> v2: > > > - check unsupported prog type like probe_bpf_helper > > > - add off parameter for module btf > > > - check verifier info when kfunc id invalid > > > - v1 > > > https://lore.kernel.org/bpf/20250122171359.232791-1-chen.dylane@xxxxxxxxx > > > > > > Tao Chen (4): > > > libbpf: Extract prog load type check from libbpf_probe_bpf_helper > > > libbpf: Init fd_array when prog probe load > > > libbpf: Add libbpf_probe_bpf_kfunc API > > > selftests/bpf: Add libbpf_probe_bpf_kfunc API selftests > > > > > > tools/lib/bpf/libbpf.h | 19 ++- > > > tools/lib/bpf/libbpf.map | 1 + > > > tools/lib/bpf/libbpf_probes.c | 86 +++++++++++--- > > > .../selftests/bpf/prog_tests/libbpf_probes.c | 111 ++++++++++++++++++ > > > 4 files changed, 201 insertions(+), 16 deletions(-) > > > > > > > Ping... > > > > Hi Andrii, Eduard, > > > > I've revised the previous suggestions. Please review it again. Thanks. > > > > I tried the test enumerating all kfuncs in BTF and doing > libbpf_probe_bpf_kfunc for BPF_PROG_TYPE_{KPROBE,XDP}. > (Source code at the end of the email). > > The set of kfuncs returned for XDP looks correct. > The set of kfuncs returned for KPROBE contains a few incorrect entries: > - bpf_xdp_metadata_rx_hash > - bpf_xdp_metadata_rx_timestamp > - bpf_xdp_metadata_rx_vlan_tag > > This is because of a different string reported by verifier for these > three functions. > > Ideally, I'd write some script looking for > register_btf_kfunc_id_set(BPF_PROG_TYPE_***, kfunc_set) > calls in the kernel source code and extracting the prog type / > functions in the set, and comparing results of this script with > output of the test below for all program types. > But up to you if you'd like to do such rigorous verification or not. > > Otherwise patch-set looks good to me, for all patch-set: > > Reviewed-by: Eduard Zingerman <eddyz87@xxxxxxxxx> Shouldn't we fix the issue with those bpf_xdp_metadata_* kfuncs? Do you have details on what different string verifier reports? > > --- 8< ----------------------------------------------------- > > static const struct { > const char *name; > int code; > } program_types[] = { > #define _T(n) { #n, BPF_PROG_TYPE_ ## n } > _T(KPROBE), > _T(XDP), > #undef _T > }; > > void test_libbpf_probe_kfuncs_many(void) > { > int i, kfunc_id, ret, id; > const struct btf_type *t; > struct btf *btf = NULL; > const char *kfunc; > const char *tag; > > btf = btf__parse("/sys/kernel/btf/vmlinux", NULL); > if (!ASSERT_OK_PTR(btf, "btf_parse")) > return; > > for (id = 0; id < btf__type_cnt(btf); ++id) { > t = btf__type_by_id(btf, id); > if (!btf_is_decl_tag(t)) > continue; > tag = btf__name_by_offset(btf, t->name_off); > if (strcmp(tag, "bpf_kfunc") != 0) > continue; > kfunc_id = t->type; > t = btf__type_by_id(btf, kfunc_id); > if (!btf_is_func(t)) > continue; > kfunc = btf__name_by_offset(btf, t->name_off); > printf("[%-6d] %-42s ", kfunc_id, kfunc); > for (i = 0; i < ARRAY_SIZE(program_types); ++i) { > ret = libbpf_probe_bpf_kfunc(program_types[i].code, kfunc_id, -1, NULL); > if (ret < 0) > printf("%-8d ", ret); > else if (ret == 0) > printf("%8s ", ""); > else > printf("%8s ", program_types[i].name); > } > printf("\n"); > } > btf__free(btf); > } > > ----------------------------------------------------- >8 --- >
