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Message-ID: <20250116143533.214496360@goodmis.org>
Date: Thu, 16 Jan 2025 09:33:35 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org,
linux-trace-kernel@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Andrew Morton <akpm@...ux-foundation.org>,
jochensp@...hen.sprickerhof.de,
peter.griffin@...aro.org
Subject: [PATCH 1/3] tracing: Add :mod: command to enabled module events
From: Steven Rostedt <rostedt@...dmis.org>
Add a :mod: command to enable only events from a given module from the
set_events file.
echo '*:mod:<module>' > set_events
Or
echo ':mod:<module>' > set_events
Will enable all events for that module. Specific events can also be
enabled via:
echo '<event>:mod:<module>' > set_events
Or
echo '<system>:<event>:mod:<module>' > set_events
Or
echo '*:<event>:mod:<module>' > set_events
The ":mod:" keyword is consistent with the function tracing filter to
enable functions from a given module.
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
Documentation/trace/events.rst | 22 +++++++++++++
kernel/trace/trace.c | 2 ++
kernel/trace/trace_events.c | 59 ++++++++++++++++++++++++++--------
3 files changed, 70 insertions(+), 13 deletions(-)
diff --git a/Documentation/trace/events.rst b/Documentation/trace/events.rst
index 759907c20e75..3db57516eb86 100644
--- a/Documentation/trace/events.rst
+++ b/Documentation/trace/events.rst
@@ -55,6 +55,28 @@ command::
# echo 'irq:*' > /sys/kernel/tracing/set_event
+The set_event file may also be used to enable events associated to only
+a specific module::
+
+ # echo ':mod:<module>' > /sys/kernel/tracing/set_event
+
+Will enable all events in the module ``<module>``.
+
+The text before ``:mod:`` will be parsed to specify specific events that the
+module creates::
+
+ # echo '<match>:mod:<module>' > /sys/kernel/tracing/set_event
+
+The above will enable any system or event that ``<match>`` matches. If
+``<match>`` is ``"*"`` then it will match all events.
+
+To enable only a specific event within a system::
+
+ # echo '<system>:<event>:mod:<module>' > /sys/kernel/tracing/set_event
+
+If ``<event>`` is ``"*"`` then it will match all events within the system
+for a given module.
+
2.2 Via the 'enable' toggle
---------------------------
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5aeb898054e7..cb85ee4a8807 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5514,6 +5514,8 @@ static const char readme_msg[] =
"\t efield: For event probes ('e' types), the field is on of the fields\n"
"\t of the <attached-group>/<attached-event>.\n"
#endif
+ " set_event\t\t- Enables events by name written into it\n"
+ "\t\t\t Can enable module events via: :mod:<module>\n"
" events/\t\t- Directory containing all trace event subsystems:\n"
" enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
" events/<system>/\t- Directory containing all trace events for <system>:\n"
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 2b9222e7bd5a..5c7d0e07618d 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1153,17 +1153,36 @@ static void remove_event_file_dir(struct trace_event_file *file)
*/
static int
__ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
- const char *sub, const char *event, int set)
+ const char *sub, const char *event, int set,
+ const char *mod)
{
struct trace_event_file *file;
struct trace_event_call *call;
+ char *module __free(kfree) = NULL;
const char *name;
int ret = -EINVAL;
int eret = 0;
+ if (mod) {
+ char *p;
+
+ module = kstrdup(mod, GFP_KERNEL);
+ if (!module)
+ return -ENOMEM;
+
+ /* Replace all '-' with '_' as that's what modules do */
+ for (p = strchr(module, '-'); p; p = strchr(p + 1, '-'))
+ *p = '_';
+ }
+
list_for_each_entry(file, &tr->events, list) {
call = file->event_call;
+
+ /* If a module is specified, skip events that are not that module */
+ if (module && (!call->module || strcmp(module_name(call->module), module)))
+ continue;
+
name = trace_event_name(call);
if (!name || !call->class || !call->class->reg)
@@ -1200,12 +1219,13 @@ __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
}
static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
- const char *sub, const char *event, int set)
+ const char *sub, const char *event, int set,
+ const char *mod)
{
int ret;
mutex_lock(&event_mutex);
- ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
+ ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set, mod);
mutex_unlock(&event_mutex);
return ret;
@@ -1213,11 +1233,20 @@ static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
{
- char *event = NULL, *sub = NULL, *match;
+ char *event = NULL, *sub = NULL, *match, *mod;
int ret;
if (!tr)
return -ENOENT;
+
+ /* Modules events can be appened with :mod:<module> */
+ mod = strstr(buf, ":mod:");
+ if (mod) {
+ *mod = '\0';
+ /* move to the module name */
+ mod += 5;
+ }
+
/*
* The buf format can be <subsystem>:<event-name>
* *:<event-name> means any event by that name.
@@ -1240,9 +1269,13 @@ int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
sub = NULL;
if (!strlen(event) || strcmp(event, "*") == 0)
event = NULL;
+ } else if (mod) {
+ /* Allow wildcard for no length or star */
+ if (!strlen(match) || strcmp(match, "*") == 0)
+ match = NULL;
}
- ret = __ftrace_set_clr_event(tr, match, sub, event, set);
+ ret = __ftrace_set_clr_event(tr, match, sub, event, set, mod);
/* Put back the colon to allow this to be called again */
if (buf)
@@ -1270,7 +1303,7 @@ int trace_set_clr_event(const char *system, const char *event, int set)
if (!tr)
return -ENODEV;
- return __ftrace_set_clr_event(tr, NULL, system, event, set);
+ return __ftrace_set_clr_event(tr, NULL, system, event, set, NULL);
}
EXPORT_SYMBOL_GPL(trace_set_clr_event);
@@ -1296,7 +1329,7 @@ int trace_array_set_clr_event(struct trace_array *tr, const char *system,
return -ENOENT;
set = (enable == true) ? 1 : 0;
- return __ftrace_set_clr_event(tr, NULL, system, event, set);
+ return __ftrace_set_clr_event(tr, NULL, system, event, set, NULL);
}
EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
@@ -1646,7 +1679,7 @@ system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
if (system)
name = system->name;
- ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
+ ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val, NULL);
if (ret)
goto out;
@@ -4094,7 +4127,7 @@ int event_trace_del_tracer(struct trace_array *tr)
__ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
/* Disable any running events */
- __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
+ __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0, NULL);
/* Make sure no more events are being executed */
tracepoint_synchronize_unregister();
@@ -4378,7 +4411,7 @@ static __init void event_trace_self_tests(void)
pr_info("Testing event system %s: ", system->name);
- ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
+ ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1, NULL);
if (WARN_ON_ONCE(ret)) {
pr_warn("error enabling system %s\n",
system->name);
@@ -4387,7 +4420,7 @@ static __init void event_trace_self_tests(void)
event_test_stuff();
- ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
+ ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0, NULL);
if (WARN_ON_ONCE(ret)) {
pr_warn("error disabling system %s\n",
system->name);
@@ -4402,7 +4435,7 @@ static __init void event_trace_self_tests(void)
pr_info("Running tests on all trace events:\n");
pr_info("Testing all events: ");
- ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
+ ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1, NULL);
if (WARN_ON_ONCE(ret)) {
pr_warn("error enabling all events\n");
return;
@@ -4411,7 +4444,7 @@ static __init void event_trace_self_tests(void)
event_test_stuff();
/* reset sysname */
- ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
+ ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0, NULL);
if (WARN_ON_ONCE(ret)) {
pr_warn("error disabling all events\n");
return;
--
2.45.2
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