| Message ID | 20210408195740.153029-1-toke@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next,1/2] bpf: return target info when a tracing bpf_link is queried | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for bpf-next |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | warning | 3 maintainers not CCed: netdev@vger.kernel.org joe@cilium.io quentin@isovalent.com |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 11983 this patch: 11983 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | warning | WARNING: line length of 96 exceeds 80 columns |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 12470 this patch: 12470 |
| netdev/header_inline | success | Link |
On Thu, Apr 8, 2021 at 12:57 PM 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. > > Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> > --- LGTM. Acked-by: Andrii Nakryiko <andrii@kernel.org> > 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;
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. 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(+)