tracing: Add show_event_filters to expose active event filters

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Currently, to audit active Ftrace event filters, userspace must
recursively traverse the events/ directory and read each individual
filter file. This is inefficient for monitoring tools and debugging.

Introduce "show_event_filters" at the trace root directory. This file
displays all events that currently have a filter applied, alongside the
actual filter string, in a consolidated system:event [tab] filter
format.

The implementation reuses the existing trace_event_file iterators to
ensure atomic traversal of the event list and utilises guard(rcu)() for
automatic, scope-based protection when accessing volatile filter
strings.

Link: https://patch.msgid.link/20260105142939.2655342-2-atomlin@atomlin.com
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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Aaron Tomlin 2026-01-05 09:29:38 -05:00 • committed by Steven Rostedt (Google)

parent e5136678b1

commit 729757b96a

2 changed files with 66 additions and 0 deletions

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8

Documentation/trace/ftrace.rst

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58

kernel/trace/trace_events.c

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