From: Mykyta Yatsenko <[email protected]> Read events/bpf_testmod/bpf_testmod_test_read/btf_ids and verify the exported FUNC_PROTO matches the testmod tracepoint signature (__data, struct task_struct *task, struct bpf_testmod_test_read_ctx *ctx) and the record struct trace_event_raw_bpf_testmod_test_read carries the fields declared by TP_STRUCT__entry.
Use the testmod tracepoint so the test exercises the module/split-BTF path (btf_relocate_id) rather than vmlinux only, and falls back from /sys/kernel/tracing to /sys/kernel/debug/tracing when tracefs is not mounted at the new location. Signed-off-by: Mykyta Yatsenko <[email protected]> --- .../testing/selftests/bpf/prog_tests/tp_btf_ids.c | 132 +++++++++++++++++++++ 1 file changed, 132 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/tp_btf_ids.c b/tools/testing/selftests/bpf/prog_tests/tp_btf_ids.c new file mode 100644 index 000000000000..c0e7e11e71b8 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/tp_btf_ids.c @@ -0,0 +1,132 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <test_progs.h> +#include <bpf/btf.h> + +#define TRACEFS "/sys/kernel/tracing" +#define DEBUGFS_TRACING "/sys/kernel/debug/tracing" +#define EVENT_SUBPATH "events/bpf_testmod/bpf_testmod_test_read/btf_ids" + +struct btf_ids_info { + __u32 obj_id; + __u32 raw_id; + __u32 tp_id; +}; + +static const char *btf_ids_path(char *buf, size_t sz) +{ + if (access(TRACEFS "/trace", F_OK) == 0) + snprintf(buf, sz, "%s/%s", TRACEFS, EVENT_SUBPATH); + else + snprintf(buf, sz, "%s/%s", DEBUGFS_TRACING, EVENT_SUBPATH); + return buf; +} + +static int read_btf_ids(struct btf_ids_info *info) +{ + char path[256], buf[256]; + int fd, n; + + fd = open(btf_ids_path(path, sizeof(path)), O_RDONLY); + if (fd < 0) + return -errno; + + n = read(fd, buf, sizeof(buf) - 1); + close(fd); + if (n <= 0) + return -EIO; + buf[n] = '\0'; + + if (sscanf(buf, + "btf_obj_id: %u\nraw_btf_id: %u\ntp_btf_id: %u\n", + &info->obj_id, &info->raw_id, &info->tp_id) != 3) + return -EINVAL; + return 0; +} + +static const char *param_name(struct btf *btf, const struct btf_param *p) +{ + return btf__name_by_offset(btf, p->name_off); +} + +static const char *member_name(struct btf *btf, const struct btf_member *m) +{ + return btf__name_by_offset(btf, m->name_off); +} + +void test_tp_btf_ids(void) +{ + const struct btf_type *proto_t, *rec_t; + const struct btf_param *params; + const struct btf_member *members; + struct btf_ids_info info; + struct btf *vmlinux_btf, *btf; + const char *name; + int err; + + if (!env.has_testmod) { + test__skip(); + return; + } + + err = read_btf_ids(&info); + if (!ASSERT_OK(err, "read btf_ids")) + return; + + ASSERT_GT(info.obj_id, 0, "obj_id non-zero"); + ASSERT_GT(info.raw_id, 0, "raw_id non-zero"); + ASSERT_GT(info.tp_id, 0, "tp_id non-zero"); + + vmlinux_btf = btf__load_vmlinux_btf(); + if (!ASSERT_OK_PTR(vmlinux_btf, "load vmlinux BTF")) + return; + + /* Module BTF is split BTF; load with vmlinux as base. */ + btf = btf__load_from_kernel_by_id_split(info.obj_id, vmlinux_btf); + if (!ASSERT_OK_PTR(btf, "load module BTF")) { + btf__free(vmlinux_btf); + return; + } + + /* + * raw_btf_id should be the FUNC_PROTO of __bpf_trace_<call>: + * void *__data, struct task_struct *task, + * struct bpf_testmod_test_read_ctx *ctx + */ + proto_t = btf__type_by_id(btf, info.raw_id); + if (!ASSERT_OK_PTR(proto_t, "raw type_by_id")) + goto out; + if (!ASSERT_TRUE(btf_is_func_proto(proto_t), "raw is FUNC_PROTO")) + goto out; + if (!ASSERT_EQ(btf_vlen(proto_t), 3, "func_proto arg count")) + goto out; + + params = btf_params(proto_t); + ASSERT_STREQ(param_name(btf, ¶ms[0]), "__data", "arg0 name"); + ASSERT_STREQ(param_name(btf, ¶ms[1]), "task", "arg1 name"); + ASSERT_STREQ(param_name(btf, ¶ms[2]), "ctx", "arg2 name"); + + /* + * tp_btf_id should be STRUCT trace_event_raw_<call> with the + * fields declared by TP_STRUCT__entry plus the common header. + */ + rec_t = btf__type_by_id(btf, info.tp_id); + if (!ASSERT_OK_PTR(rec_t, "tp type_by_id")) + goto out; + if (!ASSERT_TRUE(btf_is_struct(rec_t), "tp is STRUCT")) + goto out; + name = btf__name_by_offset(btf, rec_t->name_off); + ASSERT_STREQ(name, "trace_event_raw_bpf_testmod_test_read", + "tp struct name"); + if (!ASSERT_GE(btf_vlen(rec_t), 5, "tp struct field count")) + goto out; + + members = btf_members(rec_t); + ASSERT_STREQ(member_name(btf, &members[0]), "ent", "field0 name"); + ASSERT_STREQ(member_name(btf, &members[1]), "pid", "field1 name"); + ASSERT_STREQ(member_name(btf, &members[2]), "comm", "field2 name"); + ASSERT_STREQ(member_name(btf, &members[3]), "off", "field3 name"); + ASSERT_STREQ(member_name(btf, &members[4]), "len", "field4 name"); +out: + btf__free(btf); + btf__free(vmlinux_btf); +} -- 2.53.0-Meta
