[PATCHv2 bpf-next 00/24] bpf: Add multi uprobe link

Jiri Olsa
2023-06-20T08:35:54Z

hi,
this patchset is adding support to attach multiple uprobes and usdt probes
through new uprobe_multi link.

The current uprobe is attached through the perf event and attaching many
uprobes takes a lot of time because of that.

The main reason is that we need to install perf event for each probed function
and profile shows perf event installation (perf_install_in_context) as culprit.

The new uprobe_multi link just creates raw uprobes and attaches the bpf
program to them without perf event being involved.

In addition to being faster we also save file descriptors. For the current
uprobe attach we use extra perf event fd for each probed function. The new
link just need one fd that covers all the functions we are attaching to.

v2 changes:
- allow to run sleepable programs [Alexei]
- allow user to specify only single path [Andrii]
- pid filter support [Andrii]
- add 'u[ret]probe.multi.s' section defs [Andrii]
- add acked [Andrii]
- remove WARN_ON_ONCE in bpf_uprobe_multi_cookie [Andrii]
- merge tools uapi change with kernel change [Andrii]
- drop ref_ctr_offset from struct bpf_uprobe [Andrii]
- use generic string parsing instead of specific pattern matching
in attach_uprobe_multi [Andrii]

followup changes:
- move elf specific code into separate C object [Andrii]
- will send fill_info support when [3] is merged [Andrii]

Also available at:
https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
uprobe_multi

The support for bpftrace [2] and tetragon [1] is updated to v2 API changes.

thanks,
jirka

[1] https://github.com/cilium/tetragon/pull/936
[2] https://github.com/iovisor/bpftrace/compare/master...olsajiri:bpftrace:uprobe_multi
[3] https://lore.kernel.org/bpf/20230612151608.99661-1-laoar.shao@gmail.com/
[4] https://lore.kernel.org/bpf/20230613113119.2348619-1-jolsa@kernel.org/
---
Jiri Olsa (24):
bpf: Add multi uprobe link
bpf: Add cookies support for uprobe_multi link
bpf: Add pid filter support for uprobe_multi link
bpf: Add bpf_get_func_ip helper support for uprobe link
libbpf: Add uprobe_multi attach type and link names
libbpf: Add elf symbol iterator
libbpf: Add open_elf/close_elf functions
libbpf: Add elf_find_multi_func_offset function
libbpf: Add elf_find_pattern_func_offset function
libbpf: Add bpf_link_create support for multi uprobes
libbpf: Add bpf_program__attach_uprobe_multi_opts function
libbpf: Add support for u[ret]probe.multi[.s] program sections
libbpf: Add uprobe multi link detection
libbpf: Add uprobe multi link support to bpf_program__attach_usdt
selftests/bpf: Add uprobe_multi skel test
selftests/bpf: Add uprobe_multi api test
selftests/bpf: Add uprobe_multi link test
selftests/bpf: Add uprobe_multi test program
selftests/bpf: Add uprobe_multi bench test
selftests/bpf: Add usdt_multi test program
selftests/bpf: Add usdt_multi bench test
selftests/bpf: Add uprobe_multi cookie test
selftests/bpf: Add uprobe_multi pid filter tests
selftests/bpf: Add extra link to uprobe_multi tests

include/linux/trace_events.h | 6 ++
include/uapi/linux/bpf.h | 16 ++++
kernel/bpf/syscall.c | 14 +++-
kernel/trace/bpf_trace.c | 349 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
tools/include/uapi/linux/bpf.h | 16 ++++
tools/lib/bpf/bpf.c | 11 +++
tools/lib/bpf/bpf.h | 11 ++-
tools/lib/bpf/libbpf.c | 645 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------------------
tools/lib/bpf/libbpf.h | 31 +++++++
tools/lib/bpf/libbpf.map | 1 +
tools/lib/bpf/libbpf_internal.h | 7 ++
tools/lib/bpf/usdt.c | 120 ++++++++++++++++++++-------
tools/testing/selftests/bpf/Makefile | 10 +++
tools/testing/selftests/bpf/prog_tests/bpf_cookie.c | 78 ++++++++++++++++++
tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c | 449 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/progs/uprobe_multi.c | 110 +++++++++++++++++++++++++
tools/testing/selftests/bpf/progs/uprobe_multi_usdt.c | 16 ++++
tools/testing/selftests/bpf/uprobe_multi.c | 53 ++++++++++++
tools/testing/selftests/bpf/usdt_multi.c | 24 ++++++
19 files changed, 1841 insertions(+), 126 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
create mode 100644 tools/testing/selftests/bpf/progs/uprobe_multi.c
create mode 100644 tools/testing/selftests/bpf/progs/uprobe_multi_usdt.c
create mode 100644 tools/testing/selftests/bpf/uprobe_multi.c
create mode 100644 tools/testing/selftests/bpf/usdt_multi.c