[v7,00/10] tracing: Creation of event probe

Message

Steven Rostedt Aug. 19, 2021, 4:13 a.m. UTC

The first 5 patches of this series has had Masami's updates as well as his
acks, and will no longer be in future series, as I'll be pushing them into
my linux-next queue.

Patch 6 received an ack from Masami, but I updated it, by pulling more out
of the old patch 7 and into that patch, adding more of the enum logic into
the internal processing of the set_print_fmt() code. This way, it adds the
switch statement, such that the addition of the eprobe only needs to add a
new case.

I pulled out the code from the old patch 7 that converts the parameter for
process_fetch_insn() regs into a void pointer called rec. I figured that
should be a separate patch as it's more set up for the eprobe code, then
having to do with the eprobe code itself.

For the eprobe code, I incorporated more of Masami's comments as well as
found some minor bugs. Those updates were:

Masami's suggestions:

 - Remove "return" for void function calls in trace_event_put_ref()
 - Used bit mask over checking separate bits of flags one at a time.
 - Check for duplicate eprobes.

Fixes:

 - Check for NULL pointer for probe_cleanup as there was an error path that
   could call it with a NULL pointer.
 - Check on create that it's for an eprobe (check for 'e'). Was breaking
   updates to kprobes and uprobes that were added by dynamic_events.
 - Add paranoid check of by enum to print_fmt call.
 - Fixed error_log ^ index handling

Other updates:

 - Updated the README to include eprobes
 - Added clear_dynamic_events() to selftests, to remove them even when
   there's a dependency between them.
 - Added a selftest to test the eprobes.


Steven Rostedt (VMware) (9):
      tracing: Add DYNAMIC flag for dynamic events
      tracing: Have dynamic events have a ref counter
      tracing/probe: Have traceprobe_parse_probe_arg() take a const arg
      tracing/probes: Allow for dot delimiter as well as slash for system names
      tracing/probes: Use struct_size() instead of defining custom macros
      tracing/probe: Change traceprobe_set_print_fmt() to take a type
      tracing/probes: Have process_fetch_insn() take a void * instead of pt_regs
      selftests/ftrace: Add clear_dynamic_events() to test cases
      selftests/ftrace: Add selftest for testing eprobe events

Tzvetomir Stoyanov (VMware) (1):
      tracing: Add a probe that attaches to trace events

----
 include/linux/trace_events.h                       |  52 +-
 kernel/trace/Makefile                              |   1 +
 kernel/trace/trace.c                               |   9 +-
 kernel/trace/trace.h                               |  18 +
 kernel/trace/trace_dynevent.c                      |  38 +
 kernel/trace/trace_dynevent.h                      |   4 +-
 kernel/trace/trace_eprobe.c                        | 932 +++++++++++++++++++++
 kernel/trace/trace_event_perf.c                    |   6 +-
 kernel/trace/trace_events.c                        |  22 +-
 kernel/trace/trace_events_synth.c                  |  21 +-
 kernel/trace/trace_events_trigger.c                |  20 +-
 kernel/trace/trace_kprobe.c                        |  43 +-
 kernel/trace/trace_probe.c                         |  84 +-
 kernel/trace/trace_probe.h                         |  15 +-
 kernel/trace/trace_probe_tmpl.h                    |   6 +-
 kernel/trace/trace_uprobe.c                        |  34 +-
 .../ftrace/test.d/dynevent/add_remove_eprobe.tc    |  53 ++
 tools/testing/selftests/ftrace/test.d/functions    |  22 +
 18 files changed, 1275 insertions(+), 105 deletions(-)
 create mode 100644 kernel/trace/trace_eprobe.c
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_eprobe.tc