| Message ID | 20201201035545.3013177-1-andrii@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | Support BTF-powered BPF tracing programs for kernel modules | expand |
On 11/30/20 7:55 PM, Andrii Nakryiko wrote: > Building on top of two previous patch sets ([0] and not yet landed [1]), this > patch sets extends kernel and libbpf with support for attaching BTF-powered > raw tracepoint (tp_btf) and tracing (fentry/fexit/fmod_ret/lsm) BPF programs > to BPF hooks defined in kernel modules. > > Kernel UAPI for BPF_PROG_LOAD is extended with extra parameter > (attach_btf_obj_id) which allows to specify kernel module BTF in which the BTF > type is identifed by attach_btf_id. > > From end user perspective there are no extra actions that need to happen. > Libbpf will continue searching across all kernel module BTFs, if desired > attach BTF type is not found in vmlinux. That way it doesn't matter if BPF > hook that user is trying to attach to is built-in into vmlinux image or is > loaded in kernel module. > > Currently pahole doesn't generate BTF_KIND_FUNC info for ftrace-able static > functions in kernel modules, so expose traced function in bpf_sidecar.ko. Once bpf_sidecar.ko => bpf_testmod.ko > pahole is enhanced, we can go back to static function. > > [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=380759&state=* > [1] https://patchwork.kernel.org/project/netdevbpf/list/?series=393677&state=* > > v1->v2: > - avoid increasing bpf_reg_state by reordering fields (Alexei); > - preserve btf_data_size in struct module; > - rebase on top of v3 of patch [1]. > > Andrii Nakryiko (8): > bpf: keep module's btf_data_size intact after load > bpf: remove hard-coded btf_vmlinux assumption from BPF verifier > bpf: allow to specify kernel module BTFs when attaching BPF programs > libbpf: factor out low-level BPF program loading helper > libbpf: support attachment of BPF tracing programs to kernel modules > selftests/bpf: add tp_btf CO-RE reloc test for modules > selftests/bpf: make bpf_testmod's traceable function global > selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module > > include/linux/bpf.h | 13 +- > include/linux/bpf_verifier.h | 28 +++- > include/linux/btf.h | 7 +- > include/uapi/linux/bpf.h | 1 + > kernel/bpf/btf.c | 90 +++++++---- > kernel/bpf/syscall.c | 44 +++++- > kernel/bpf/verifier.c | 77 ++++++---- > kernel/module.c | 1 - > net/ipv4/bpf_tcp_ca.c | 3 +- > tools/include/uapi/linux/bpf.h | 1 + > tools/lib/bpf/bpf.c | 101 ++++++++---- > tools/lib/bpf/libbpf.c | 145 +++++++++++++----- > tools/lib/bpf/libbpf_internal.h | 30 ++++ > .../selftests/bpf/bpf_testmod/bpf_testmod.c | 3 +- > .../selftests/bpf/prog_tests/core_reloc.c | 3 +- > .../selftests/bpf/prog_tests/module_attach.c | 53 +++++++ > .../bpf/progs/test_core_reloc_module.c | 32 +++- > .../selftests/bpf/progs/test_module_attach.c | 66 ++++++++ > 18 files changed, 546 insertions(+), 152 deletions(-) > create mode 100644 tools/testing/selftests/bpf/prog_tests/module_attach.c > create mode 100644 tools/testing/selftests/bpf/progs/test_module_attach.c >
On Mon, Nov 30, 2020 at 11:26 PM Yonghong Song <yhs@fb.com> wrote: > > > > On 11/30/20 7:55 PM, Andrii Nakryiko wrote: > > Building on top of two previous patch sets ([0] and not yet landed [1]), this > > patch sets extends kernel and libbpf with support for attaching BTF-powered > > raw tracepoint (tp_btf) and tracing (fentry/fexit/fmod_ret/lsm) BPF programs > > to BPF hooks defined in kernel modules. > > > > Kernel UAPI for BPF_PROG_LOAD is extended with extra parameter > > (attach_btf_obj_id) which allows to specify kernel module BTF in which the BTF > > type is identifed by attach_btf_id. > > > > From end user perspective there are no extra actions that need to happen. > > Libbpf will continue searching across all kernel module BTFs, if desired > > attach BTF type is not found in vmlinux. That way it doesn't matter if BPF > > hook that user is trying to attach to is built-in into vmlinux image or is > > loaded in kernel module. > > > > Currently pahole doesn't generate BTF_KIND_FUNC info for ftrace-able static > > functions in kernel modules, so expose traced function in bpf_sidecar.ko. Once > > bpf_sidecar.ko => bpf_testmod.ko > will fix, thanks! > > pahole is enhanced, we can go back to static function. > > > > [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=380759&state=* > > [1] https://patchwork.kernel.org/project/netdevbpf/list/?series=393677&state=* > > > > v1->v2: > > - avoid increasing bpf_reg_state by reordering fields (Alexei); > > - preserve btf_data_size in struct module; > > - rebase on top of v3 of patch [1]. > > > > Andrii Nakryiko (8): > > bpf: keep module's btf_data_size intact after load > > bpf: remove hard-coded btf_vmlinux assumption from BPF verifier > > bpf: allow to specify kernel module BTFs when attaching BPF programs > > libbpf: factor out low-level BPF program loading helper > > libbpf: support attachment of BPF tracing programs to kernel modules > > selftests/bpf: add tp_btf CO-RE reloc test for modules > > selftests/bpf: make bpf_testmod's traceable function global > > selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module > > > > include/linux/bpf.h | 13 +- > > include/linux/bpf_verifier.h | 28 +++- > > include/linux/btf.h | 7 +- > > include/uapi/linux/bpf.h | 1 + > > kernel/bpf/btf.c | 90 +++++++---- > > kernel/bpf/syscall.c | 44 +++++- > > kernel/bpf/verifier.c | 77 ++++++---- > > kernel/module.c | 1 - > > net/ipv4/bpf_tcp_ca.c | 3 +- > > tools/include/uapi/linux/bpf.h | 1 + > > tools/lib/bpf/bpf.c | 101 ++++++++---- > > tools/lib/bpf/libbpf.c | 145 +++++++++++++----- > > tools/lib/bpf/libbpf_internal.h | 30 ++++ > > .../selftests/bpf/bpf_testmod/bpf_testmod.c | 3 +- > > .../selftests/bpf/prog_tests/core_reloc.c | 3 +- > > .../selftests/bpf/prog_tests/module_attach.c | 53 +++++++ > > .../bpf/progs/test_core_reloc_module.c | 32 +++- > > .../selftests/bpf/progs/test_module_attach.c | 66 ++++++++ > > 18 files changed, 546 insertions(+), 152 deletions(-) > > create mode 100644 tools/testing/selftests/bpf/prog_tests/module_attach.c > > create mode 100644 tools/testing/selftests/bpf/progs/test_module_attach.c > >