On Wed, 26 Nov 2025 13:41:07 -0500
"Seokwoo Chung (Ryan)" <[email protected]> wrote:
> Extend fprobe to support list-style filters and explicit entry/exit suffixes.
> Currentyl, fprobe only supports a single symbol (or wildcard) per event.
> This patch allows users to specify a comma-separated list of symbols.
>
> New Syntax:
> - f:[GRP/][EVENT] func1,func2,func3:entry
> - f:[GRP/][EVENT] func1,func2,func3:exit
Thanks for updating!
>
> Logic changes:
> - Refactor parsing logic into 'parse_fprobe_spec'
> - Support '!' prefix for exclusion
> - Disable BTF lookup ('ctx->funcname = NULL') when a list or wildcard is used,
> as a single function signature cannot apply to multiple functions.
> - Reject legacy '%return' suffix when used with lists or wildcards
> - Update tracefs/README
>
> Testing:
> Verified on x86_64 via QEMU. Checked registration of lists, exclusions, and
> explicit suffixes. Verified rejection of invalid syntax including trailing
> commas and mixed legacy/new syntax.
>
> Seokwoo Chung (Ryan) (3):
> docs: tracing/fprobe: Document list filters and :entry/:exit
> tracing/fprobe: Support comma-separated symbols and :entry/:exit
For the next time, please add docs patch after code change because of bisect.
(Or, include the document update into code update.)
> selftests/ftrace: Add accept cases for fprobe list syntax
Testing after code is good. :)
Thank you,
>
> Changes in v4:
> - Added validation to reject trailing commas (empty tokens) in symbol lists
> - Added vaildation to reject mixed of list syntax with %return suffix
> - Refactored parse_fprobe_spec to user __free(kfree) for automatic memory
> cleanup
> - Removed the now-unused parse_symbol_and_return function to avoid compiler
> warnings.
> - Tigtened %return detection to ensure it only matches as a strict suffix,
> not a
> substring
> - Link to v3:
> https://lore.kernel.org/lkml/[email protected]/
>
> Documentation/trace/fprobetrace.rst | 17 +-
> kernel/trace/trace.c | 3 +-
> kernel/trace/trace_fprobe.c | 209 ++++++++++++++----
> .../ftrace/test.d/dynevent/fprobe_list.tc | 92 ++++++++
> 4 files changed, 269 insertions(+), 52 deletions(-)
> create mode 100644
> tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc
>
> --
> 2.43.0
>
--
Masami Hiramatsu (Google) <[email protected]>
