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
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
selftests/ftrace: Add accept cases for fprobe list syntax
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
