* [PATCH bpf-next v2 1/2] bpf: return target info when a tracing bpf_link is queried @ 2021-04-13 9:16 Toke Høiland-Jørgensen 2021-04-13 9:16 ` [PATCH bpf-next v2 2/2] selftests/bpf: add tests for target information in bpf_link info queries Toke Høiland-Jørgensen 2021-04-14 1:25 ` [PATCH bpf-next v2 1/2] bpf: return target info when a tracing bpf_link is queried Alexei Starovoitov 0 siblings, 2 replies; 3+ messages in thread From: Toke Høiland-Jørgensen @ 2021-04-13 9:16 UTC (permalink / raw) To: Alexei Starovoitov, Daniel Borkmann Cc: Toke Høiland-Jørgensen, Andrii Nakryiko, Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev, bpf There is currently no way to discover the target of a tracing program attachment after the fact. Add this information to bpf_link_info and return it when querying the bpf_link fd. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> --- include/linux/bpf_verifier.h | 9 +++++++++ include/uapi/linux/bpf.h | 2 ++ kernel/bpf/syscall.c | 3 +++ tools/include/uapi/linux/bpf.h | 2 ++ 4 files changed, 16 insertions(+) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 51c2ffa3d901..6023a1367853 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -487,6 +487,15 @@ static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog, return ((u64)btf_obj_id(btf) << 32) | 0x80000000 | btf_id; } +/* unpack the IDs from the key as constructed above */ +static inline void bpf_trampoline_unpack_key(u64 key, u32 *obj_id, u32 *btf_id) +{ + if (obj_id) + *obj_id = key >> 32; + if (btf_id) + *btf_id = key & 0x7FFFFFFF; +} + int bpf_check_attach_target(struct bpf_verifier_log *log, const struct bpf_prog *prog, const struct bpf_prog *tgt_prog, diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 49371eba98ba..397884396671 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5379,6 +5379,8 @@ struct bpf_link_info { } raw_tracepoint; struct { __u32 attach_type; + __u32 target_obj_id; /* prog_id for PROG_EXT, otherwise btf object id */ + __u32 target_btf_id; /* BTF type id inside the object */ } tracing; struct { __u64 cgroup_id; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 6428634da57e..fd495190115e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2551,6 +2551,9 @@ static int bpf_tracing_link_fill_link_info(const struct bpf_link *link, container_of(link, struct bpf_tracing_link, link); info->tracing.attach_type = tr_link->attach_type; + bpf_trampoline_unpack_key(tr_link->trampoline->key, + &info->tracing.target_obj_id, + &info->tracing.target_btf_id); return 0; } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 69902603012c..1a240be873d7 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -5373,6 +5373,8 @@ struct bpf_link_info { } raw_tracepoint; struct { __u32 attach_type; + __u32 target_obj_id; /* prog_id for PROG_EXT, otherwise btf object id */ + __u32 target_btf_id; /* BTF type id inside the object */ } tracing; struct { __u64 cgroup_id; -- 2.31.1 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH bpf-next v2 2/2] selftests/bpf: add tests for target information in bpf_link info queries 2021-04-13 9:16 [PATCH bpf-next v2 1/2] bpf: return target info when a tracing bpf_link is queried Toke Høiland-Jørgensen @ 2021-04-13 9:16 ` Toke Høiland-Jørgensen 2021-04-14 1:25 ` [PATCH bpf-next v2 1/2] bpf: return target info when a tracing bpf_link is queried Alexei Starovoitov 1 sibling, 0 replies; 3+ messages in thread From: Toke Høiland-Jørgensen @ 2021-04-13 9:16 UTC (permalink / raw) To: Alexei Starovoitov, Daniel Borkmann Cc: Toke Høiland-Jørgensen, Andrii Nakryiko, Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev, bpf Extend the fexit_bpf2bpf test to check that the info for the bpf_link returned by the kernel matches the expected values. While we're updating the test, change existing uses of CHEC() to use the much easier to read ASSERT_*() macros. v2: - Convert last CHECK() call and get rid of 'duration' var - Split ASSERT_OK_PTR() checks to two separate if statements Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> --- .../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 58 ++++++++++++++----- 1 file changed, 44 insertions(+), 14 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c index 5c0448910426..63990842d20f 100644 --- a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c +++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c @@ -58,42 +58,73 @@ static void test_fexit_bpf2bpf_common(const char *obj_file, test_cb cb) { struct bpf_object *obj = NULL, *tgt_obj; + __u32 retval, tgt_prog_id, info_len; + struct bpf_prog_info prog_info = {}; struct bpf_program **prog = NULL; struct bpf_link **link = NULL; - __u32 duration = 0, retval; int err, tgt_fd, i; + struct btf *btf; err = bpf_prog_load(target_obj_file, BPF_PROG_TYPE_UNSPEC, &tgt_obj, &tgt_fd); - if (CHECK(err, "tgt_prog_load", "file %s err %d errno %d\n", - target_obj_file, err, errno)) + if (!ASSERT_OK(err, "tgt_prog_load")) return; DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts, .attach_prog_fd = tgt_fd, ); + info_len = sizeof(prog_info); + err = bpf_obj_get_info_by_fd(tgt_fd, &prog_info, &info_len); + if (!ASSERT_OK(err, "tgt_fd_get_info")) + goto close_prog; + + tgt_prog_id = prog_info.id; + btf = bpf_object__btf(tgt_obj); + link = calloc(sizeof(struct bpf_link *), prog_cnt); + if (!ASSERT_OK_PTR(link, "link_ptr")) + goto close_prog; + prog = calloc(sizeof(struct bpf_program *), prog_cnt); - if (CHECK(!link || !prog, "alloc_memory", "failed to alloc memory")) + if (!ASSERT_OK_PTR(prog, "prog_ptr")) goto close_prog; obj = bpf_object__open_file(obj_file, &opts); - if (CHECK(IS_ERR_OR_NULL(obj), "obj_open", - "failed to open %s: %ld\n", obj_file, - PTR_ERR(obj))) + if (!ASSERT_OK_PTR(obj, "obj_open")) goto close_prog; err = bpf_object__load(obj); - if (CHECK(err, "obj_load", "err %d\n", err)) + if (!ASSERT_OK(err, "obj_load")) goto close_prog; for (i = 0; i < prog_cnt; i++) { + struct bpf_link_info link_info; + char *tgt_name; + __s32 btf_id; + + tgt_name = strstr(prog_name[i], "/"); + if (!ASSERT_OK_PTR(tgt_name, "tgt_name")) + goto close_prog; + btf_id = btf__find_by_name_kind(btf, tgt_name + 1, BTF_KIND_FUNC); + prog[i] = bpf_object__find_program_by_title(obj, prog_name[i]); - if (CHECK(!prog[i], "find_prog", "prog %s not found\n", prog_name[i])) + if (!ASSERT_OK_PTR(prog[i], prog_name[i])) goto close_prog; + link[i] = bpf_program__attach_trace(prog[i]); - if (CHECK(IS_ERR(link[i]), "attach_trace", "failed to link\n")) + if (!ASSERT_OK_PTR(link[i], "attach_trace")) goto close_prog; + + info_len = sizeof(link_info); + memset(&link_info, 0, sizeof(link_info)); + err = bpf_obj_get_info_by_fd(bpf_link__fd(link[i]), + &link_info, &info_len); + ASSERT_OK(err, "link_fd_get_info"); + ASSERT_EQ(link_info.tracing.attach_type, + bpf_program__get_expected_attach_type(prog[i]), + "link_attach_type"); + ASSERT_EQ(link_info.tracing.target_obj_id, tgt_prog_id, "link_tgt_obj_id"); + ASSERT_EQ(link_info.tracing.target_btf_id, btf_id, "link_tgt_btf_id"); } if (cb) { @@ -106,10 +137,9 @@ static void test_fexit_bpf2bpf_common(const char *obj_file, goto close_prog; err = bpf_prog_test_run(tgt_fd, 1, &pkt_v6, sizeof(pkt_v6), - NULL, NULL, &retval, &duration); - CHECK(err || retval, "ipv6", - "err %d errno %d retval %d duration %d\n", - err, errno, retval, duration); + NULL, NULL, &retval, NULL); + ASSERT_OK(err, "prog_run"); + ASSERT_EQ(retval, 0, "prog_run_ret"); if (check_data_map(obj, prog_cnt, false)) goto close_prog; -- 2.31.1 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v2 1/2] bpf: return target info when a tracing bpf_link is queried 2021-04-13 9:16 [PATCH bpf-next v2 1/2] bpf: return target info when a tracing bpf_link is queried Toke Høiland-Jørgensen 2021-04-13 9:16 ` [PATCH bpf-next v2 2/2] selftests/bpf: add tests for target information in bpf_link info queries Toke Høiland-Jørgensen @ 2021-04-14 1:25 ` Alexei Starovoitov 1 sibling, 0 replies; 3+ messages in thread From: Alexei Starovoitov @ 2021-04-14 1:25 UTC (permalink / raw) To: Toke Høiland-Jørgensen Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev, bpf On Tue, Apr 13, 2021 at 2:16 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote: > > There is currently no way to discover the target of a tracing program > attachment after the fact. Add this information to bpf_link_info and return > it when querying the bpf_link fd. > > Acked-by: Andrii Nakryiko <andrii@kernel.org> > Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Applied. Thanks ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-04-14 1:26 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-04-13 9:16 [PATCH bpf-next v2 1/2] bpf: return target info when a tracing bpf_link is queried Toke Høiland-Jørgensen 2021-04-13 9:16 ` [PATCH bpf-next v2 2/2] selftests/bpf: add tests for target information in bpf_link info queries Toke Høiland-Jørgensen 2021-04-14 1:25 ` [PATCH bpf-next v2 1/2] bpf: return target info when a tracing bpf_link is queried Alexei Starovoitov
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