[PATCH RFC 6/7] tracing: Add a filter argument to __ftrace_set_clr_event()
From: Thomas Weißschuh
Date: Thu Aug 13 2026 - 10:09:21 EST
Make it possible to directly enable a filter when enabling an event.
For now this is unused, an upcoming patch will wire it up.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
---
kernel/trace/trace_events.c | 47 +++++++++++++++++++++++++++++----------------
1 file changed, 30 insertions(+), 17 deletions(-)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 098a5aee5ec7..c24929d003dd 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -916,6 +916,7 @@ struct event_mod_load {
char *match;
char *system;
char *event;
+ char *filter;
};
static void free_event_mod(struct event_mod_load *event_mod)
@@ -925,6 +926,7 @@ static void free_event_mod(struct event_mod_load *event_mod)
kfree(event_mod->match);
kfree(event_mod->system);
kfree(event_mod->event);
+ kfree(event_mod->filter);
kfree(event_mod);
}
@@ -966,7 +968,7 @@ static int remove_cache_mod(struct trace_array *tr, const char *mod,
}
static int cache_mod(struct trace_array *tr, const char *mod, int set,
- const char *match, const char *system, const char *event)
+ const char *match, const char *system, const char *event, const char *filter)
{
struct event_mod_load *event_mod;
@@ -1005,6 +1007,12 @@ static int cache_mod(struct trace_array *tr, const char *mod, int set,
goto out_free;
}
+ if (filter) {
+ event_mod->filter = kstrdup(filter, GFP_KERNEL);
+ if (!event_mod->filter)
+ goto out_free;
+ }
+
list_add(&event_mod->list, &tr->mod_events);
return 0;
@@ -1017,7 +1025,7 @@ static int cache_mod(struct trace_array *tr, const char *mod, int set,
#else /* CONFIG_MODULES */
static inline void clear_mod_events(struct trace_array *tr) { }
static int cache_mod(struct trace_array *tr, const char *mod, int set,
- const char *match, const char *system, const char *event)
+ const char *match, const char *system, const char *event, const char *filter)
{
return -EINVAL;
}
@@ -1326,7 +1334,7 @@ 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 *mod)
+ const char *mod, char *filter)
{
struct trace_event_file *file;
struct trace_event_call *call;
@@ -1374,7 +1382,11 @@ __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
if (event && strcmp(event, name) != 0)
continue;
- ret = ftrace_event_enable_disable(file, set);
+ if (filter)
+ ret = apply_event_filter(file, filter);
+
+ if (!filter || !ret)
+ ret = ftrace_event_enable_disable(file, set);
/*
* Save the first error and return that. Some events
@@ -1392,14 +1404,14 @@ __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
* check if the module was loaded. If it wasn't cache it.
*/
if (module && ret == -EINVAL && !eret)
- ret = cache_mod(tr, module, set, match, sub, event);
+ ret = cache_mod(tr, module, set, match, sub, event, filter);
return ret;
}
static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
const char *sub, const char *event, int set,
- const char *mod)
+ const char *mod, char *filter)
{
int ret;
@@ -1407,7 +1419,7 @@ static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
return -EACCES;
mutex_lock(&event_mutex);
- ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set, mod);
+ ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set, mod, filter);
mutex_unlock(&event_mutex);
return ret;
@@ -1470,7 +1482,7 @@ int ftrace_set_clr_event(struct trace_array *tr, const char *_buf, int set)
ftrace_parse_event_string(buf, &match, &sub, &event, &mod);
- return __ftrace_set_clr_event(tr, match, sub, event, set, mod);
+ return __ftrace_set_clr_event(tr, match, sub, event, set, mod, NULL);
}
/**
@@ -1492,7 +1504,7 @@ 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, NULL);
+ return __ftrace_set_clr_event(tr, NULL, system, event, set, NULL, NULL);
}
EXPORT_SYMBOL_GPL(trace_set_clr_event);
@@ -1518,7 +1530,7 @@ 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, NULL);
+ return __ftrace_set_clr_event(tr, NULL, system, event, set, NULL, NULL);
}
EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
@@ -2038,7 +2050,7 @@ 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, NULL);
+ ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val, NULL, NULL);
if (ret)
goto out;
@@ -3909,7 +3921,8 @@ static void update_mod_cache(struct trace_array *tr, struct module *mod)
__ftrace_set_clr_event_nolock(tr, event_mod->match,
event_mod->system,
- event_mod->event, 1, mod->name);
+ event_mod->event, 1, mod->name,
+ event_mod->filter);
free_event_mod(event_mod);
}
}
@@ -4676,7 +4689,7 @@ 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, NULL);
+ __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0, NULL, NULL);
/* Make sure no more events are being executed */
tracepoint_synchronize_unregister();
@@ -4982,7 +4995,7 @@ 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, NULL);
+ ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1, NULL, NULL);
if (WARN_ON_ONCE(ret)) {
pr_warn("error enabling system %s\n",
system->name);
@@ -4991,7 +5004,7 @@ static __init void event_trace_self_tests(void)
event_test_stuff();
- ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0, NULL);
+ ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0, NULL, NULL);
if (WARN_ON_ONCE(ret)) {
pr_warn("error disabling system %s\n",
system->name);
@@ -5006,7 +5019,7 @@ 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, NULL);
+ ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1, NULL, NULL);
if (WARN_ON_ONCE(ret)) {
pr_warn("error enabling all events\n");
return;
@@ -5015,7 +5028,7 @@ static __init void event_trace_self_tests(void)
event_test_stuff();
/* reset sysname */
- ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0, NULL);
+ ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0, NULL, NULL);
if (WARN_ON_ONCE(ret)) {
pr_warn("error disabling all events\n");
return;
--
2.55.0