[bpf-next,v2,0/3] add support for writable bare tracepoint

Message

Hou Tao Sept. 18, 2021, 2:09 a.m. UTC

Hi,

The patchset series supports writable context for bare tracepoint.

The main idea comes from patchset "writable contexts for bpf raw
tracepoints" [1], but it only supports normal tracepoint with
associated trace event under tracefs. Now we want to add a
bare tracepoint in VFS layer, and update file::f_mode for specific
files. The reason using bare tracepoint is that it doesn't form
a ABI and we can change it freely. So add support for it in BPF.

Any comments are welcome.

[1]: https://lore.kernel.org/lkml/[e-mail]

Change log:
v2:
  * rebase on bpf-next tree
  * address comments from Yonghong Song
  * rename bpf_testmode_test_writable_ctx::ret as early_ret to reflect
    its purpose better.

v1:
  * https://www.spinics.net/lists/bpf/msg46221.html

Hou Tao (3):
  bpf: support writable context for bare tracepoint
  libbpf: support detecting and attaching of writable tracepoint program
  bpf/selftests: add test for writable bare tracepoint

 include/trace/bpf_probe.h                     | 19 +++++++---
 tools/lib/bpf/libbpf.c                        |  4 +++
 .../bpf/bpf_testmod/bpf_testmod-events.h      | 15 ++++++++
 .../selftests/bpf/bpf_testmod/bpf_testmod.c   | 10 ++++++
 .../selftests/bpf/bpf_testmod/bpf_testmod.h   |  5 +++
 .../selftests/bpf/prog_tests/module_attach.c  | 36 +++++++++++++++++++
 .../selftests/bpf/progs/test_module_attach.c  | 14 ++++++++
 7 files changed, 99 insertions(+), 4 deletions(-)