Re: [PATCH v6 0/4] tracing/fprobe: Support comma-separated symbol lists and :entry/:exit suffixes

Masami Hiramatsu
2026-03-24T01:51:36Z

Hi,

Sorry, I completely missed this series. Let me review it.

Thank you,

On Thu, 5 Feb 2026 08:58:38 -0500
"Seokwoo Chung (Ryan)" <seokwoo.chung130@gmail.com> wrote:

> Extend the fprobe event interface to accept comma-separated symbol lists
> with ! exclusion prefix, and :entry/:exit suffixes as an alternative to
> %return. Single-symbol probes retain full backward compatibility with
> %return.
>
> Example usage:
> f:mygroup/myevent vfs_read,!vfs_write,vfs_open:entry
> f:mygroup/myexit vfs_read,vfs_open:exit
>
> Changes since v5:
> - Fix missing closing brace in the empty-token check that caused a
> build error.
> - Remove redundant strchr/strstr checks for tracepoint validation;
> the character validation loop already rejects ',', ':', and '%'.
> - Add trace_probe_log_err() to the tracepoint character validation
> loop so users see what went wrong in tracefs/error_log (reviewer
> feedback from Masami Hiramatsu).
> - Remove unnecessary braces around single-statement if per kernel
> coding style (reviewer feedback).
> - Extract list parsing into parse_fprobe_list() to keep
> parse_fprobe_spec() focused (reviewer feedback).
> - New patch 2/4: add glob_match_comma_list() in kernel/trace/fprobe.c
> so register_fprobe() correctly handles comma-separated filter
> strings. Without this, enabling a list-mode fprobe event failed
> with "Could not enable event" because glob_match() does not
> understand commas.
> - Reorder: documentation patch now comes after all code changes.
> - Updated selftest commit message to note that existing tests
> (add_remove_fprobe.tc, fprobe_syntax_errors.tc,
> add_remove_fprobe_repeat.tc) report UNSUPPORTED because their
> "requires" lines still check for the old %return syntax in README.
> Their requires lines need updating in a follow-up patch.
>
> Tested in QEMU/KVM but I am not too confident if I configured correctly and
> would like to ask for further testing.
>
> Seokwoo Chung (Ryan) (4):
> tracing/fprobe: Support comma-separated symbols and :entry/:exit
> fprobe: Support comma-separated filters in register_fprobe()
> docs: tracing/fprobe: Document list filters and :entry/:exit
> selftests/ftrace: Add accept cases for fprobe list syntax
>
> Documentation/trace/fprobetrace.rst | 17 +-
> kernel/trace/fprobe.c | 30 ++-
> kernel/trace/trace.c | 3 +-
> kernel/trace/trace_fprobe.c | 219 ++++++++++++++----
> .../ftrace/test.d/dynevent/fprobe_list.tc | 92 ++++++++
> 5 files changed, 308 insertions(+), 53 deletions(-)
> create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc
>
> --
> 2.43.0