| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20260105142939.2655342-3-atomlin@atomlin.com>
Date: Mon, 5 Jan 2026 09:29:39 -0500
From: Aaron Tomlin <atomlin@...mlin.com>
To: rostedt@...dmis.org,
mhiramat@...nel.org,
mark.rutland@....com,
mathieu.desnoyers@...icios.com,
corbet@....net
Cc: neelx@...e.com,
sean@...e.io,
linux-kernel@...r.kernel.org,
linux-trace-kernel@...r.kernel.org,
linux-doc@...r.kernel.org
Subject: [v2 PATCH 2/2] tracing: Add show_event_triggers to expose active event triggers
To audit active event triggers, userspace currently must traverse the
events/ directory and read each individual trigger file. This is
cumbersome for system-wide auditing or debugging.
Introduce "show_event_triggers" at the trace root directory. This file
displays all events that currently have one or more triggers applied,
alongside the trigger configuration, in a consolidated
system:event [tab] trigger format.
The implementation leverages the existing trace_event_file iterators
and uses the trigger's own print() operation to ensure output
consistency with the per-event trigger files.
Signed-off-by: Aaron Tomlin <atomlin@...mlin.com>
---
Documentation/trace/ftrace.rst | 8 +++++
kernel/trace/trace_events.c | 64 ++++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+)
diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 4ce01e726b09..b9efb148a5c2 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -692,6 +692,14 @@ of ftrace. Here is a list of some of the key files:
See events.rst for more information.
+ show_event_triggers:
+
+ A list of events that have triggers. This shows the
+ system/event pair along with the trigger that is attached to
+ the event.
+
+ See events.rst for more information.
+
available_events:
A list of events that can be enabled in tracing.
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 5ede4214c4df..e2a67561253d 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1687,6 +1687,38 @@ static int t_show_filters(struct seq_file *m, void *v)
return 0;
}
+/**
+ * t_show_triggers - seq_file callback to display active event triggers
+ * @m: The seq_file interface for formatted output
+ * @v: The current trace_event_file being iterated
+ *
+ * Iterates through the trigger list of the current event file and prints
+ * each active trigger's configuration using its associated print
+ * operation.
+ */
+static int t_show_triggers(struct seq_file *m, void *v)
+{
+ struct trace_event_file *file = v;
+ struct trace_event_call *call = file->event_call;
+ struct event_trigger_data *data;
+
+ /*
+ * The event_mutex is held by t_start(), protecting the
+ * file->triggers list traversal.
+ */
+ if (list_empty(&file->triggers))
+ return 0;
+
+ list_for_each_entry_rcu(data, &file->triggers, list) {
+ seq_printf(m, "%s:%s\t", call->class->system,
+ trace_event_name(call));
+
+ data->cmd_ops->print(m, data);
+ }
+
+ return 0;
+}
+
#ifdef CONFIG_MODULES
static int s_show(struct seq_file *m, void *v)
{
@@ -2515,6 +2547,7 @@ ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
static int ftrace_event_avail_open(struct inode *inode, struct file *file);
static int ftrace_event_set_open(struct inode *inode, struct file *file);
static int ftrace_event_show_filters_open(struct inode *inode, struct file *file);
+static int ftrace_event_show_triggers_open(struct inode *inode, struct file *file);
static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
static int ftrace_event_release(struct inode *inode, struct file *file);
@@ -2540,6 +2573,13 @@ static const struct seq_operations show_show_event_filters_seq_ops = {
.stop = t_stop,
};
+static const struct seq_operations show_show_event_triggers_seq_ops = {
+ .start = t_start,
+ .next = t_next,
+ .show = t_show_triggers,
+ .stop = t_stop,
+};
+
static const struct seq_operations show_set_pid_seq_ops = {
.start = p_start,
.next = p_next,
@@ -2576,6 +2616,13 @@ static const struct file_operations ftrace_show_event_filters_fops = {
.release = seq_release,
};
+static const struct file_operations ftrace_show_event_triggers_fops = {
+ .open = ftrace_event_show_triggers_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
static const struct file_operations ftrace_set_event_pid_fops = {
.open = ftrace_event_set_pid_open,
.read = seq_read,
@@ -2734,6 +2781,20 @@ ftrace_event_show_filters_open(struct inode *inode, struct file *file)
return ftrace_event_open(inode, file, &show_show_event_filters_seq_ops);
}
+/**
+ * ftrace_event_show_triggers_open - open interface for show_event_triggers
+ * @inode: The inode of the file
+ * @file: The file being opened
+ *
+ * Connects the show_event_triggers file to the sequence operations
+ * required to iterate over and display active event triggers.
+ */
+static int
+ftrace_event_show_triggers_open(struct inode *inode, struct file *file)
+{
+ return ftrace_event_open(inode, file, &show_show_event_triggers_seq_ops);
+}
+
static int
ftrace_event_set_pid_open(struct inode *inode, struct file *file)
{
@@ -4457,6 +4518,9 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
trace_create_file("show_event_filters", TRACE_MODE_READ, parent, tr,
&ftrace_show_event_filters_fops);
+ trace_create_file("show_event_triggers", TRACE_MODE_READ, parent, tr,
+ &ftrace_show_event_triggers_fops);
+
nr_entries = ARRAY_SIZE(events_entries);
e_events = eventfs_create_events_dir("events", parent, events_entries,
--
2.51.0
Powered by blists - more mailing lists