* [PATCH 6.12.y 2/4] tracing: Remove get_trigger_ops() and add count_func() from trigger ops
2026-09-16 19:03 ` [PATCH 6.12.y 1/4] tracing: Constify struct event_trigger_ops Sasha Levin
@ 2026-09-16 19:03 ` Sasha Levin
2026-09-16 19:03 ` [PATCH 6.12.y 3/4] tracing: Merge struct event_trigger_ops into struct event_command Sasha Levin
2026-09-16 19:03 ` [PATCH 6.12.y 4/4] tracing: Take the reference before publishing the named histogram trigger Sasha Levin
2 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2026-09-16 19:03 UTC (permalink / raw)
To: stable
Cc: Steven Rostedt, Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Andrew Morton, Tom Zanussi, Sasha Levin
From: Steven Rostedt <rostedt@goodmis.org>
[ Upstream commit bdafb4d4cb3bb18b29517eaae09fb49d25f854f0 ]
The struct event_command has a callback function called get_trigger_ops().
This callback returns the "trigger_ops" to use for the trigger. These ops
define the trigger function, how to init the trigger, how to print the
trigger and how to free it.
The only reason there's a callback function to get these ops is because
some triggers have two types of operations. One is an "always on"
operation, and the other is a "count down" operation. If a user passes in
a parameter to say how many times the trigger should execute. For example:
echo stacktrace:5 > events/kmem/kmem_cache_alloc/trigger
It will trigger the stacktrace for the first 5 times the kmem_cache_alloc
event is hit.
Instead of having two different trigger_ops since the only difference
between them is the tigger itself (the print, init and free functions are
all the same), just use a single ops that the event_command points to and
add a function field to the trigger_ops to have a count_func.
When a trigger is added to an event, if there's a count attached to it and
the trigger ops has the count_func field, the data allocated to represent
this trigger will have a new flag set called COUNT.
Then when the trigger executes, it will check if the COUNT data flag is
set, and if so, it will call the ops count_func(). If that returns false,
it returns without executing the trigger.
This removes the need for duplicate event_trigger_ops structures.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://patch.msgid.link/20251125200932.274566147@kernel.org
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Stable-dep-of: 0fe23b8eaba0 ("tracing: Take the reference before publishing the named histogram trigger")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/trace/trace.h | 26 ++-
kernel/trace/trace_eprobe.c | 8 +-
kernel/trace/trace_events_hist.c | 60 +------
kernel/trace/trace_events_trigger.c | 257 ++++++++++------------------
4 files changed, 116 insertions(+), 235 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 327c01655585d..7a2c5b42d76e3 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1692,6 +1692,7 @@ extern void clear_event_triggers(struct trace_array *tr);
enum {
EVENT_TRIGGER_FL_PROBE = BIT(0),
+ EVENT_TRIGGER_FL_COUNT = BIT(1),
};
struct event_trigger_data {
@@ -1723,6 +1724,10 @@ struct enable_trigger_data {
bool hist;
};
+bool event_trigger_count(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event);
+
extern int event_enable_trigger_print(struct seq_file *m,
struct event_trigger_data *data);
extern void event_enable_trigger_free(struct event_trigger_data *data);
@@ -1810,6 +1815,11 @@ extern void event_file_put(struct trace_event_file *file);
* registered the trigger (see struct event_command) along with
* the trace record, rec.
*
+ * @count_func: If defined and a numeric parameter is passed to the
+ * trigger, then this function will be called before @trigger
+ * is called. If this function returns false, then @trigger is not
+ * executed.
+ *
* @init: An optional initialization function called for the trigger
* when the trigger is registered (via the event_command reg()
* function). This can be used to perform per-trigger
@@ -1837,6 +1847,10 @@ struct event_trigger_ops {
struct trace_buffer *buffer,
void *rec,
struct ring_buffer_event *rbe);
+ bool (*count_func)(struct event_trigger_data *data,
+ struct trace_buffer *buffer,
+ void *rec,
+ struct ring_buffer_event *rbe);
int (*init)(struct event_trigger_data *data);
void (*free)(struct event_trigger_data *data);
int (*print)(struct seq_file *m,
@@ -1863,6 +1877,9 @@ struct event_trigger_ops {
* @name: The unique name that identifies the event command. This is
* the name used when setting triggers via trigger files.
*
+ * @trigger_ops: The event_trigger_ops implementation associated with
+ * the command.
+ *
* @trigger_type: A unique id that identifies the event command
* 'type'. This value has two purposes, the first to ensure that
* only one trigger of the same type can be set at a given time
@@ -1914,17 +1931,11 @@ struct event_trigger_ops {
* event command, filters set by the user for the command will be
* ignored. This is usually implemented by the generic utility
* function @set_trigger_filter() (see trace_event_triggers.c).
- *
- * @get_trigger_ops: The callback function invoked to retrieve the
- * event_trigger_ops implementation associated with the command.
- * This callback function allows a single event_command to
- * support multiple trigger implementations via different sets of
- * event_trigger_ops, depending on the value of the @param
- * string.
*/
struct event_command {
struct list_head list;
char *name;
+ const struct event_trigger_ops *trigger_ops;
enum event_trigger_type trigger_type;
int flags;
int (*parse)(struct event_command *cmd_ops,
@@ -1941,7 +1952,6 @@ struct event_command {
int (*set_filter)(char *filter_str,
struct event_trigger_data *data,
struct trace_event_file *file);
- const struct event_trigger_ops *(*get_trigger_ops)(char *cmd, char *param);
};
/**
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 06436fe0786e8..f6c80dfe227b6 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -508,21 +508,15 @@ static void eprobe_trigger_unreg_func(char *glob,
}
-static const struct event_trigger_ops *eprobe_trigger_get_ops(char *cmd,
- char *param)
-{
- return &eprobe_trigger_ops;
-}
-
static struct event_command event_trigger_cmd = {
.name = "eprobe",
.trigger_type = ETT_EVENT_EPROBE,
.flags = EVENT_CMD_FL_NEEDS_REC,
+ .trigger_ops = &eprobe_trigger_ops,
.parse = eprobe_trigger_cmd_parse,
.reg = eprobe_trigger_reg_func,
.unreg = eprobe_trigger_unreg_func,
.unreg_all = NULL,
- .get_trigger_ops = eprobe_trigger_get_ops,
.set_filter = NULL,
};
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 96d7091995793..52e9342073b79 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -6363,12 +6363,6 @@ static const struct event_trigger_ops event_hist_trigger_named_ops = {
.free = event_hist_trigger_named_free,
};
-static const struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
- char *param)
-{
- return &event_hist_trigger_ops;
-}
-
static void hist_clear(struct event_trigger_data *data)
{
struct hist_trigger_data *hist_data = data->private_data;
@@ -6910,11 +6904,11 @@ static struct event_command trigger_hist_cmd = {
.name = "hist",
.trigger_type = ETT_EVENT_HIST,
.flags = EVENT_CMD_FL_NEEDS_REC,
+ .trigger_ops = &event_hist_trigger_ops,
.parse = event_hist_trigger_parse,
.reg = hist_register_trigger,
.unreg = hist_unregister_trigger,
.unreg_all = hist_unreg_all,
- .get_trigger_ops = event_hist_get_trigger_ops,
.set_filter = set_trigger_filter,
};
@@ -6947,29 +6941,9 @@ hist_enable_trigger(struct event_trigger_data *data,
}
}
-static void
-hist_enable_count_trigger(struct event_trigger_data *data,
- struct trace_buffer *buffer, void *rec,
- struct ring_buffer_event *event)
-{
- if (!data->count)
- return;
-
- if (data->count != -1)
- (data->count)--;
-
- hist_enable_trigger(data, buffer, rec, event);
-}
-
static const struct event_trigger_ops hist_enable_trigger_ops = {
.trigger = hist_enable_trigger,
- .print = event_enable_trigger_print,
- .init = event_trigger_init,
- .free = event_enable_trigger_free,
-};
-
-static const struct event_trigger_ops hist_enable_count_trigger_ops = {
- .trigger = hist_enable_count_trigger,
+ .count_func = event_trigger_count,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
@@ -6977,36 +6951,12 @@ static const struct event_trigger_ops hist_enable_count_trigger_ops = {
static const struct event_trigger_ops hist_disable_trigger_ops = {
.trigger = hist_enable_trigger,
+ .count_func = event_trigger_count,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
-static const struct event_trigger_ops hist_disable_count_trigger_ops = {
- .trigger = hist_enable_count_trigger,
- .print = event_enable_trigger_print,
- .init = event_trigger_init,
- .free = event_enable_trigger_free,
-};
-
-static const struct event_trigger_ops *
-hist_enable_get_trigger_ops(char *cmd, char *param)
-{
- const struct event_trigger_ops *ops;
- bool enable;
-
- enable = (strcmp(cmd, ENABLE_HIST_STR) == 0);
-
- if (enable)
- ops = param ? &hist_enable_count_trigger_ops :
- &hist_enable_trigger_ops;
- else
- ops = param ? &hist_disable_count_trigger_ops :
- &hist_disable_trigger_ops;
-
- return ops;
-}
-
static void hist_enable_unreg_all(struct trace_event_file *file)
{
struct event_trigger_data *test, *n;
@@ -7025,22 +6975,22 @@ static void hist_enable_unreg_all(struct trace_event_file *file)
static struct event_command trigger_hist_enable_cmd = {
.name = ENABLE_HIST_STR,
.trigger_type = ETT_HIST_ENABLE,
+ .trigger_ops = &hist_enable_trigger_ops,
.parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.unreg_all = hist_enable_unreg_all,
- .get_trigger_ops = hist_enable_get_trigger_ops,
.set_filter = set_trigger_filter,
};
static struct event_command trigger_hist_disable_cmd = {
.name = DISABLE_HIST_STR,
.trigger_type = ETT_HIST_ENABLE,
+ .trigger_ops = &hist_disable_trigger_ops,
.parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.unreg_all = hist_enable_unreg_all,
- .get_trigger_ops = hist_enable_get_trigger_ops,
.set_filter = set_trigger_filter,
};
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index d153a10ae50e1..41122a81e7966 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -31,6 +31,20 @@ void trigger_data_free(struct event_trigger_data *data)
kfree(data);
}
+static inline void data_ops_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ const struct event_trigger_ops *ops = data->ops;
+
+ if (data->flags & EVENT_TRIGGER_FL_COUNT) {
+ if (!ops->count_func(data, buffer, rec, event))
+ return;
+ }
+
+ ops->trigger(data, buffer, rec, event);
+}
+
/**
* event_triggers_call - Call triggers associated with a trace event
* @file: The trace_event_file associated with the event
@@ -73,7 +87,7 @@ event_triggers_call(struct trace_event_file *file,
if (data->paused)
continue;
if (!rec) {
- data->ops->trigger(data, buffer, rec, event);
+ data_ops_trigger(data, buffer, rec, event);
continue;
}
filter = rcu_dereference_sched(data->filter);
@@ -83,7 +97,7 @@ event_triggers_call(struct trace_event_file *file,
tt |= data->cmd_ops->trigger_type;
continue;
}
- data->ops->trigger(data, buffer, rec, event);
+ data_ops_trigger(data, buffer, rec, event);
}
return tt;
}
@@ -125,7 +139,7 @@ event_triggers_post_call(struct trace_event_file *file,
if (data->paused)
continue;
if (data->cmd_ops->trigger_type & tt)
- data->ops->trigger(data, NULL, NULL, NULL);
+ data_ops_trigger(data, NULL, NULL, NULL);
}
}
EXPORT_SYMBOL_GPL(event_triggers_post_call);
@@ -401,6 +415,36 @@ __init int unregister_event_command(struct event_command *cmd)
return ret;
}
+/**
+ * event_trigger_count - Optional count function for event triggers
+ * @data: Trigger-specific data
+ * @buffer: The ring buffer that the event is being written to
+ * @rec: The trace entry for the event, NULL for unconditional invocation
+ * @event: The event meta data in the ring buffer
+ *
+ * For triggers that can take a count parameter that doesn't do anything
+ * special, they can use this function to assign to their .count_func
+ * field.
+ *
+ * This simply does a count down of the @data->count field.
+ *
+ * If the @data->count is greater than zero, it will decrement it.
+ *
+ * Returns false if @data->count is zero, otherwise true.
+ */
+bool event_trigger_count(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ if (!data->count)
+ return false;
+
+ if (data->count != -1)
+ (data->count)--;
+
+ return true;
+}
+
/**
* event_trigger_print - Generic event_trigger_ops @print implementation
* @name: The name of the event trigger
@@ -835,9 +879,13 @@ int event_trigger_separate_filter(char *param_and_filter, char **param,
* @private_data: User data to associate with the event trigger
*
* Allocate an event_trigger_data instance and initialize it. The
- * @cmd_ops are used along with the @cmd and @param to get the
- * trigger_ops to assign to the event_trigger_data. @private_data can
- * also be passed in and associated with the event_trigger_data.
+ * @cmd_ops defines how the trigger will operate. If @param is set,
+ * and @cmd_ops->trigger_ops->count_func is non NULL, then the
+ * data->count is set to @param and before the trigger is executed, the
+ * @cmd_ops->trigger_ops->count_func() is called. If that function returns
+ * false, the @cmd_ops->trigger_ops->trigger() function will not be called.
+ * @private_data can also be passed in and associated with the
+ * event_trigger_data.
*
* Use trigger_data_free() to free an event_trigger_data object.
*
@@ -849,18 +897,17 @@ struct event_trigger_data *trigger_data_alloc(struct event_command *cmd_ops,
void *private_data)
{
struct event_trigger_data *trigger_data;
- const struct event_trigger_ops *trigger_ops;
-
- trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
if (!trigger_data)
return NULL;
trigger_data->count = -1;
- trigger_data->ops = trigger_ops;
+ trigger_data->ops = cmd_ops->trigger_ops;
trigger_data->cmd_ops = cmd_ops;
trigger_data->private_data = private_data;
+ if (param && cmd_ops->trigger_ops->count_func)
+ trigger_data->flags |= EVENT_TRIGGER_FL_COUNT;
INIT_LIST_HEAD(&trigger_data->list);
INIT_LIST_HEAD(&trigger_data->named_list);
@@ -1302,31 +1349,28 @@ traceon_trigger(struct event_trigger_data *data,
tracing_on();
}
-static void
-traceon_count_trigger(struct event_trigger_data *data,
- struct trace_buffer *buffer, void *rec,
- struct ring_buffer_event *event)
+static bool
+traceon_count_func(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
{
struct trace_event_file *file = data->private_data;
if (file) {
if (tracer_tracing_is_on(file->tr))
- return;
+ return false;
} else {
if (tracing_is_on())
- return;
+ return false;
}
if (!data->count)
- return;
+ return false;
if (data->count != -1)
(data->count)--;
- if (file)
- tracer_tracing_on(file->tr);
- else
- tracing_on();
+ return true;
}
static void
@@ -1350,31 +1394,28 @@ traceoff_trigger(struct event_trigger_data *data,
tracing_off();
}
-static void
-traceoff_count_trigger(struct event_trigger_data *data,
- struct trace_buffer *buffer, void *rec,
- struct ring_buffer_event *event)
+static bool
+traceoff_count_func(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
{
struct trace_event_file *file = data->private_data;
if (file) {
if (!tracer_tracing_is_on(file->tr))
- return;
+ return false;
} else {
if (!tracing_is_on())
- return;
+ return false;
}
if (!data->count)
- return;
+ return false;
if (data->count != -1)
(data->count)--;
- if (file)
- tracer_tracing_off(file->tr);
- else
- tracing_off();
+ return true;
}
static int
@@ -1393,13 +1434,7 @@ traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data)
static const struct event_trigger_ops traceon_trigger_ops = {
.trigger = traceon_trigger,
- .print = traceon_trigger_print,
- .init = event_trigger_init,
- .free = event_trigger_free,
-};
-
-static const struct event_trigger_ops traceon_count_trigger_ops = {
- .trigger = traceon_count_trigger,
+ .count_func = traceon_count_func,
.print = traceon_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
@@ -1407,41 +1442,19 @@ static const struct event_trigger_ops traceon_count_trigger_ops = {
static const struct event_trigger_ops traceoff_trigger_ops = {
.trigger = traceoff_trigger,
+ .count_func = traceoff_count_func,
.print = traceoff_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
-static const struct event_trigger_ops traceoff_count_trigger_ops = {
- .trigger = traceoff_count_trigger,
- .print = traceoff_trigger_print,
- .init = event_trigger_init,
- .free = event_trigger_free,
-};
-
-static const struct event_trigger_ops *
-onoff_get_trigger_ops(char *cmd, char *param)
-{
- const struct event_trigger_ops *ops;
-
- /* we register both traceon and traceoff to this callback */
- if (strcmp(cmd, "traceon") == 0)
- ops = param ? &traceon_count_trigger_ops :
- &traceon_trigger_ops;
- else
- ops = param ? &traceoff_count_trigger_ops :
- &traceoff_trigger_ops;
-
- return ops;
-}
-
static struct event_command trigger_traceon_cmd = {
.name = "traceon",
.trigger_type = ETT_TRACE_ONOFF,
+ .trigger_ops = &traceon_trigger_ops,
.parse = event_trigger_parse,
.reg = register_trigger,
.unreg = unregister_trigger,
- .get_trigger_ops = onoff_get_trigger_ops,
.set_filter = set_trigger_filter,
};
@@ -1449,10 +1462,10 @@ static struct event_command trigger_traceoff_cmd = {
.name = "traceoff",
.trigger_type = ETT_TRACE_ONOFF,
.flags = EVENT_CMD_FL_POST_TRIGGER,
+ .trigger_ops = &traceoff_trigger_ops,
.parse = event_trigger_parse,
.reg = register_trigger,
.unreg = unregister_trigger,
- .get_trigger_ops = onoff_get_trigger_ops,
.set_filter = set_trigger_filter,
};
@@ -1470,20 +1483,6 @@ snapshot_trigger(struct event_trigger_data *data,
tracing_snapshot();
}
-static void
-snapshot_count_trigger(struct event_trigger_data *data,
- struct trace_buffer *buffer, void *rec,
- struct ring_buffer_event *event)
-{
- if (!data->count)
- return;
-
- if (data->count != -1)
- (data->count)--;
-
- snapshot_trigger(data, buffer, rec, event);
-}
-
static int
register_snapshot_trigger(char *glob,
struct event_trigger_data *data,
@@ -1517,31 +1516,19 @@ snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data)
static const struct event_trigger_ops snapshot_trigger_ops = {
.trigger = snapshot_trigger,
+ .count_func = event_trigger_count,
.print = snapshot_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
-static const struct event_trigger_ops snapshot_count_trigger_ops = {
- .trigger = snapshot_count_trigger,
- .print = snapshot_trigger_print,
- .init = event_trigger_init,
- .free = event_trigger_free,
-};
-
-static const struct event_trigger_ops *
-snapshot_get_trigger_ops(char *cmd, char *param)
-{
- return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
-}
-
static struct event_command trigger_snapshot_cmd = {
.name = "snapshot",
.trigger_type = ETT_SNAPSHOT,
+ .trigger_ops = &snapshot_trigger_ops,
.parse = event_trigger_parse,
.reg = register_snapshot_trigger,
.unreg = unregister_snapshot_trigger,
- .get_trigger_ops = snapshot_get_trigger_ops,
.set_filter = set_trigger_filter,
};
@@ -1589,20 +1576,6 @@ stacktrace_trigger(struct event_trigger_data *data,
trace_dump_stack(STACK_SKIP);
}
-static void
-stacktrace_count_trigger(struct event_trigger_data *data,
- struct trace_buffer *buffer, void *rec,
- struct ring_buffer_event *event)
-{
- if (!data->count)
- return;
-
- if (data->count != -1)
- (data->count)--;
-
- stacktrace_trigger(data, buffer, rec, event);
-}
-
static int
stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data)
{
@@ -1612,32 +1585,20 @@ stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data)
static const struct event_trigger_ops stacktrace_trigger_ops = {
.trigger = stacktrace_trigger,
+ .count_func = event_trigger_count,
.print = stacktrace_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
-static const struct event_trigger_ops stacktrace_count_trigger_ops = {
- .trigger = stacktrace_count_trigger,
- .print = stacktrace_trigger_print,
- .init = event_trigger_init,
- .free = event_trigger_free,
-};
-
-static const struct event_trigger_ops *
-stacktrace_get_trigger_ops(char *cmd, char *param)
-{
- return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
-}
-
static struct event_command trigger_stacktrace_cmd = {
.name = "stacktrace",
.trigger_type = ETT_STACKTRACE,
+ .trigger_ops = &stacktrace_trigger_ops,
.flags = EVENT_CMD_FL_POST_TRIGGER,
.parse = event_trigger_parse,
.reg = register_trigger,
.unreg = unregister_trigger,
- .get_trigger_ops = stacktrace_get_trigger_ops,
.set_filter = set_trigger_filter,
};
@@ -1673,24 +1634,24 @@ event_enable_trigger(struct event_trigger_data *data,
set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
}
-static void
-event_enable_count_trigger(struct event_trigger_data *data,
- struct trace_buffer *buffer, void *rec,
- struct ring_buffer_event *event)
+static bool
+event_enable_count_func(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
{
struct enable_trigger_data *enable_data = data->private_data;
if (!data->count)
- return;
+ return false;
/* Skip if the event is in a state we want to switch to */
if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
- return;
+ return false;
if (data->count != -1)
(data->count)--;
- event_enable_trigger(data, buffer, rec, event);
+ return true;
}
int event_enable_trigger_print(struct seq_file *m,
@@ -1737,13 +1698,7 @@ void event_enable_trigger_free(struct event_trigger_data *data)
static const struct event_trigger_ops event_enable_trigger_ops = {
.trigger = event_enable_trigger,
- .print = event_enable_trigger_print,
- .init = event_trigger_init,
- .free = event_enable_trigger_free,
-};
-
-static const struct event_trigger_ops event_enable_count_trigger_ops = {
- .trigger = event_enable_count_trigger,
+ .count_func = event_enable_count_func,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
@@ -1751,13 +1706,7 @@ static const struct event_trigger_ops event_enable_count_trigger_ops = {
static const struct event_trigger_ops event_disable_trigger_ops = {
.trigger = event_enable_trigger,
- .print = event_enable_trigger_print,
- .init = event_trigger_init,
- .free = event_enable_trigger_free,
-};
-
-static const struct event_trigger_ops event_disable_count_trigger_ops = {
- .trigger = event_enable_count_trigger,
+ .count_func = event_enable_count_func,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
@@ -1940,45 +1889,23 @@ void event_enable_unregister_trigger(char *glob,
data->ops->free(data);
}
-static const struct event_trigger_ops *
-event_enable_get_trigger_ops(char *cmd, char *param)
-{
- const struct event_trigger_ops *ops;
- bool enable;
-
-#ifdef CONFIG_HIST_TRIGGERS
- enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
- (strcmp(cmd, ENABLE_HIST_STR) == 0));
-#else
- enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
-#endif
- if (enable)
- ops = param ? &event_enable_count_trigger_ops :
- &event_enable_trigger_ops;
- else
- ops = param ? &event_disable_count_trigger_ops :
- &event_disable_trigger_ops;
-
- return ops;
-}
-
static struct event_command trigger_enable_cmd = {
.name = ENABLE_EVENT_STR,
.trigger_type = ETT_EVENT_ENABLE,
+ .trigger_ops = &event_enable_trigger_ops,
.parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
- .get_trigger_ops = event_enable_get_trigger_ops,
.set_filter = set_trigger_filter,
};
static struct event_command trigger_disable_cmd = {
.name = DISABLE_EVENT_STR,
.trigger_type = ETT_EVENT_ENABLE,
+ .trigger_ops = &event_disable_trigger_ops,
.parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
- .get_trigger_ops = event_enable_get_trigger_ops,
.set_filter = set_trigger_filter,
};
--
2.53.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 6.12.y 3/4] tracing: Merge struct event_trigger_ops into struct event_command
2026-09-16 19:03 ` [PATCH 6.12.y 1/4] tracing: Constify struct event_trigger_ops Sasha Levin
2026-09-16 19:03 ` [PATCH 6.12.y 2/4] tracing: Remove get_trigger_ops() and add count_func() from trigger ops Sasha Levin
@ 2026-09-16 19:03 ` Sasha Levin
2026-09-16 19:03 ` [PATCH 6.12.y 4/4] tracing: Take the reference before publishing the named histogram trigger Sasha Levin
2 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2026-09-16 19:03 UTC (permalink / raw)
To: stable
Cc: Steven Rostedt, Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Andrew Morton, Tom Zanussi, Sasha Levin
From: Steven Rostedt <rostedt@goodmis.org>
[ Upstream commit b052d70f7c9c156409a70e65c10d83b5650e7e78 ]
Now that there's pretty much a one to one mapping between the struct
event_trigger_ops and struct event_command, there's no reason to have two
different structures. Merge the function pointers of event_trigger_ops
into event_command.
There's one exception in trace_events_hist.c for the
event_hist_trigger_named_ops. This has special logic for the init and free
function pointers for "named histograms". In this case, allocate the
cmd_ops of the event_trigger_data and set it to the proper init and free
functions, which are used to initialize and free the event_trigger_data
respectively. Have the free function and the init function (on failure)
free the cmd_ops of the data element.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://patch.msgid.link/20251125200932.446322765@kernel.org
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Stable-dep-of: 0fe23b8eaba0 ("tracing: Take the reference before publishing the named histogram trigger")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/trace/trace.h | 126 +++++++++++-----------------
kernel/trace/trace_eprobe.c | 13 +--
kernel/trace/trace_events_hist.c | 93 ++++++++++----------
kernel/trace/trace_events_trigger.c | 121 +++++++++++---------------
4 files changed, 151 insertions(+), 202 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 7a2c5b42d76e3..495bbc42b4a87 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1699,7 +1699,6 @@ struct event_trigger_data {
unsigned long count;
int ref;
int flags;
- const struct event_trigger_ops *ops;
struct event_command *cmd_ops;
struct event_filter __rcu *filter;
char *filter_str;
@@ -1790,73 +1789,6 @@ extern void event_trigger_unregister(struct event_command *cmd_ops,
extern void event_file_get(struct trace_event_file *file);
extern void event_file_put(struct trace_event_file *file);
-/**
- * struct event_trigger_ops - callbacks for trace event triggers
- *
- * The methods in this structure provide per-event trigger hooks for
- * various trigger operations.
- *
- * The @init and @free methods are used during trigger setup and
- * teardown, typically called from an event_command's @parse()
- * function implementation.
- *
- * The @print method is used to print the trigger spec.
- *
- * The @trigger method is the function that actually implements the
- * trigger and is called in the context of the triggering event
- * whenever that event occurs.
- *
- * All the methods below, except for @init() and @free(), must be
- * implemented.
- *
- * @trigger: The trigger 'probe' function called when the triggering
- * event occurs. The data passed into this callback is the data
- * that was supplied to the event_command @reg() function that
- * registered the trigger (see struct event_command) along with
- * the trace record, rec.
- *
- * @count_func: If defined and a numeric parameter is passed to the
- * trigger, then this function will be called before @trigger
- * is called. If this function returns false, then @trigger is not
- * executed.
- *
- * @init: An optional initialization function called for the trigger
- * when the trigger is registered (via the event_command reg()
- * function). This can be used to perform per-trigger
- * initialization such as incrementing a per-trigger reference
- * count, for instance. This is usually implemented by the
- * generic utility function @event_trigger_init() (see
- * trace_event_triggers.c).
- *
- * @free: An optional de-initialization function called for the
- * trigger when the trigger is unregistered (via the
- * event_command @reg() function). This can be used to perform
- * per-trigger de-initialization such as decrementing a
- * per-trigger reference count and freeing corresponding trigger
- * data, for instance. This is usually implemented by the
- * generic utility function @event_trigger_free() (see
- * trace_event_triggers.c).
- *
- * @print: The callback function invoked to have the trigger print
- * itself. This is usually implemented by a wrapper function
- * that calls the generic utility function @event_trigger_print()
- * (see trace_event_triggers.c).
- */
-struct event_trigger_ops {
- void (*trigger)(struct event_trigger_data *data,
- struct trace_buffer *buffer,
- void *rec,
- struct ring_buffer_event *rbe);
- bool (*count_func)(struct event_trigger_data *data,
- struct trace_buffer *buffer,
- void *rec,
- struct ring_buffer_event *rbe);
- int (*init)(struct event_trigger_data *data);
- void (*free)(struct event_trigger_data *data);
- int (*print)(struct seq_file *m,
- struct event_trigger_data *data);
-};
-
/**
* struct event_command - callbacks and data members for event commands
*
@@ -1877,9 +1809,6 @@ struct event_trigger_ops {
* @name: The unique name that identifies the event command. This is
* the name used when setting triggers via trigger files.
*
- * @trigger_ops: The event_trigger_ops implementation associated with
- * the command.
- *
* @trigger_type: A unique id that identifies the event command
* 'type'. This value has two purposes, the first to ensure that
* only one trigger of the same type can be set at a given time
@@ -1909,7 +1838,7 @@ struct event_trigger_ops {
*
* @reg: Adds the trigger to the list of triggers associated with the
* event, and enables the event trigger itself, after
- * initializing it (via the event_trigger_ops @init() function).
+ * initializing it (via the event_command @init() function).
* This is also where commands can use the @trigger_type value to
* make the decision as to whether or not multiple instances of
* the trigger should be allowed. This is usually implemented by
@@ -1918,7 +1847,7 @@ struct event_trigger_ops {
*
* @unreg: Removes the trigger from the list of triggers associated
* with the event, and disables the event trigger itself, after
- * initializing it (via the event_trigger_ops @free() function).
+ * initializing it (via the event_command @free() function).
* This is usually implemented by the generic utility function
* @unregister_trigger() (see trace_event_triggers.c).
*
@@ -1931,11 +1860,46 @@ struct event_trigger_ops {
* event command, filters set by the user for the command will be
* ignored. This is usually implemented by the generic utility
* function @set_trigger_filter() (see trace_event_triggers.c).
+ *
+ * All the methods below, except for @init() and @free(), must be
+ * implemented.
+ *
+ * @trigger: The trigger 'probe' function called when the triggering
+ * event occurs. The data passed into this callback is the data
+ * that was supplied to the event_command @reg() function that
+ * registered the trigger (see struct event_command) along with
+ * the trace record, rec.
+ *
+ * @count_func: If defined and a numeric parameter is passed to the
+ * trigger, then this function will be called before @trigger
+ * is called. If this function returns false, then @trigger is not
+ * executed.
+ *
+ * @init: An optional initialization function called for the trigger
+ * when the trigger is registered (via the event_command reg()
+ * function). This can be used to perform per-trigger
+ * initialization such as incrementing a per-trigger reference
+ * count, for instance. This is usually implemented by the
+ * generic utility function @event_trigger_init() (see
+ * trace_event_triggers.c).
+ *
+ * @free: An optional de-initialization function called for the
+ * trigger when the trigger is unregistered (via the
+ * event_command @reg() function). This can be used to perform
+ * per-trigger de-initialization such as decrementing a
+ * per-trigger reference count and freeing corresponding trigger
+ * data, for instance. This is usually implemented by the
+ * generic utility function @event_trigger_free() (see
+ * trace_event_triggers.c).
+ *
+ * @print: The callback function invoked to have the trigger print
+ * itself. This is usually implemented by a wrapper function
+ * that calls the generic utility function @event_trigger_print()
+ * (see trace_event_triggers.c).
*/
struct event_command {
struct list_head list;
char *name;
- const struct event_trigger_ops *trigger_ops;
enum event_trigger_type trigger_type;
int flags;
int (*parse)(struct event_command *cmd_ops,
@@ -1952,6 +1916,18 @@ struct event_command {
int (*set_filter)(char *filter_str,
struct event_trigger_data *data,
struct trace_event_file *file);
+ void (*trigger)(struct event_trigger_data *data,
+ struct trace_buffer *buffer,
+ void *rec,
+ struct ring_buffer_event *rbe);
+ bool (*count_func)(struct event_trigger_data *data,
+ struct trace_buffer *buffer,
+ void *rec,
+ struct ring_buffer_event *rbe);
+ int (*init)(struct event_trigger_data *data);
+ void (*free)(struct event_trigger_data *data);
+ int (*print)(struct seq_file *m,
+ struct event_trigger_data *data);
};
/**
@@ -1972,7 +1948,7 @@ struct event_command {
* either committed or discarded. At that point, if any commands
* have deferred their triggers, those commands are finally
* invoked following the close of the current event. In other
- * words, if the event_trigger_ops @func() probe implementation
+ * words, if the event_command @func() probe implementation
* itself logs to the trace buffer, this flag should be set,
* otherwise it can be left unspecified.
*
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index f6c80dfe227b6..88bf2ec8b0c7c 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -479,13 +479,6 @@ static void eprobe_trigger_func(struct event_trigger_data *data,
__eprobe_trace_func(edata, rec);
}
-static const struct event_trigger_ops eprobe_trigger_ops = {
- .trigger = eprobe_trigger_func,
- .print = eprobe_trigger_print,
- .init = eprobe_trigger_init,
- .free = eprobe_trigger_free,
-};
-
static int eprobe_trigger_cmd_parse(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob, char *cmd,
@@ -512,12 +505,15 @@ static struct event_command event_trigger_cmd = {
.name = "eprobe",
.trigger_type = ETT_EVENT_EPROBE,
.flags = EVENT_CMD_FL_NEEDS_REC,
- .trigger_ops = &eprobe_trigger_ops,
.parse = eprobe_trigger_cmd_parse,
.reg = eprobe_trigger_reg_func,
.unreg = eprobe_trigger_unreg_func,
.unreg_all = NULL,
.set_filter = NULL,
+ .trigger = eprobe_trigger_func,
+ .print = eprobe_trigger_print,
+ .init = eprobe_trigger_init,
+ .free = eprobe_trigger_free,
};
static struct event_trigger_data *
@@ -537,7 +533,6 @@ new_eprobe_trigger(struct trace_eprobe *ep, struct trace_event_file *file)
trigger->flags = EVENT_TRIGGER_FL_PROBE;
trigger->count = -1;
- trigger->ops = &eprobe_trigger_ops;
/*
* EVENT PROBE triggers are not registered as commands with
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 52e9342073b79..7b0fc0bb62f0b 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -5696,7 +5696,7 @@ static void hist_trigger_show(struct seq_file *m,
seq_puts(m, "\n\n");
seq_puts(m, "# event histogram\n#\n# trigger info: ");
- data->ops->print(m, data);
+ data->cmd_ops->print(m, data);
seq_puts(m, "#\n\n");
hist_data = data->private_data;
@@ -6018,7 +6018,7 @@ static void hist_trigger_debug_show(struct seq_file *m,
seq_puts(m, "\n\n");
seq_puts(m, "# event histogram\n#\n# trigger info: ");
- data->ops->print(m, data);
+ data->cmd_ops->print(m, data);
seq_puts(m, "#\n\n");
hist_data = data->private_data;
@@ -6326,20 +6326,21 @@ static void event_hist_trigger_free(struct event_trigger_data *data)
free_hist_pad();
}
-static const struct event_trigger_ops event_hist_trigger_ops = {
- .trigger = event_hist_trigger,
- .print = event_hist_trigger_print,
- .init = event_hist_trigger_init,
- .free = event_hist_trigger_free,
-};
-
static int event_hist_trigger_named_init(struct event_trigger_data *data)
{
+ int ret;
+
data->ref++;
save_named_trigger(data->named_data->name, data);
- return event_hist_trigger_init(data->named_data);
+ ret = event_hist_trigger_init(data->named_data);
+ if (ret < 0) {
+ kfree(data->cmd_ops);
+ data->cmd_ops = &trigger_hist_cmd;
+ }
+
+ return ret;
}
static void event_hist_trigger_named_free(struct event_trigger_data *data)
@@ -6351,18 +6352,14 @@ static void event_hist_trigger_named_free(struct event_trigger_data *data)
data->ref--;
if (!data->ref) {
+ struct event_command *cmd_ops = data->cmd_ops;
+
del_named_trigger(data);
trigger_data_free(data);
+ kfree(cmd_ops);
}
}
-static const struct event_trigger_ops event_hist_trigger_named_ops = {
- .trigger = event_hist_trigger,
- .print = event_hist_trigger_print,
- .init = event_hist_trigger_named_init,
- .free = event_hist_trigger_named_free,
-};
-
static void hist_clear(struct event_trigger_data *data)
{
struct hist_trigger_data *hist_data = data->private_data;
@@ -6556,13 +6553,24 @@ static int hist_register_trigger(char *glob,
data->paused = true;
if (named_data) {
+ struct event_command *cmd_ops;
+
data->private_data = named_data->private_data;
set_named_trigger_data(data, named_data);
- data->ops = &event_hist_trigger_named_ops;
+ /* Copy the command ops and update some of the functions */
+ cmd_ops = kmalloc(sizeof(*cmd_ops), GFP_KERNEL);
+ if (!cmd_ops) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ *cmd_ops = *data->cmd_ops;
+ cmd_ops->init = event_hist_trigger_named_init;
+ cmd_ops->free = event_hist_trigger_named_free;
+ data->cmd_ops = cmd_ops;
}
- if (data->ops->init) {
- ret = data->ops->init(data);
+ if (data->cmd_ops->init) {
+ ret = data->cmd_ops->init(data);
if (ret < 0)
goto out;
}
@@ -6678,8 +6686,8 @@ static void hist_unregister_trigger(char *glob,
}
}
- if (test && test->ops->free)
- test->ops->free(test);
+ if (test && test->cmd_ops->free)
+ test->cmd_ops->free(test);
if (hist_data->enable_timestamps) {
if (!hist_data->remove || test)
@@ -6731,8 +6739,8 @@ static void hist_unreg_all(struct trace_event_file *file)
update_cond_flag(file);
if (hist_data->enable_timestamps)
tracing_set_filter_buffering(file->tr, false);
- if (test->ops->free)
- test->ops->free(test);
+ if (test->cmd_ops->free)
+ test->cmd_ops->free(test);
}
}
}
@@ -6904,12 +6912,15 @@ static struct event_command trigger_hist_cmd = {
.name = "hist",
.trigger_type = ETT_EVENT_HIST,
.flags = EVENT_CMD_FL_NEEDS_REC,
- .trigger_ops = &event_hist_trigger_ops,
.parse = event_hist_trigger_parse,
.reg = hist_register_trigger,
.unreg = hist_unregister_trigger,
.unreg_all = hist_unreg_all,
.set_filter = set_trigger_filter,
+ .trigger = event_hist_trigger,
+ .print = event_hist_trigger_print,
+ .init = event_hist_trigger_init,
+ .free = event_hist_trigger_free,
};
__init int register_trigger_hist_cmd(void)
@@ -6941,22 +6952,6 @@ hist_enable_trigger(struct event_trigger_data *data,
}
}
-static const struct event_trigger_ops hist_enable_trigger_ops = {
- .trigger = hist_enable_trigger,
- .count_func = event_trigger_count,
- .print = event_enable_trigger_print,
- .init = event_trigger_init,
- .free = event_enable_trigger_free,
-};
-
-static const struct event_trigger_ops hist_disable_trigger_ops = {
- .trigger = hist_enable_trigger,
- .count_func = event_trigger_count,
- .print = event_enable_trigger_print,
- .init = event_trigger_init,
- .free = event_enable_trigger_free,
-};
-
static void hist_enable_unreg_all(struct trace_event_file *file)
{
struct event_trigger_data *test, *n;
@@ -6966,8 +6961,8 @@ static void hist_enable_unreg_all(struct trace_event_file *file)
list_del_rcu(&test->list);
update_cond_flag(file);
trace_event_trigger_enable_disable(file, 0);
- if (test->ops->free)
- test->ops->free(test);
+ if (test->cmd_ops->free)
+ test->cmd_ops->free(test);
}
}
}
@@ -6975,23 +6970,31 @@ static void hist_enable_unreg_all(struct trace_event_file *file)
static struct event_command trigger_hist_enable_cmd = {
.name = ENABLE_HIST_STR,
.trigger_type = ETT_HIST_ENABLE,
- .trigger_ops = &hist_enable_trigger_ops,
.parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.unreg_all = hist_enable_unreg_all,
.set_filter = set_trigger_filter,
+ .trigger = hist_enable_trigger,
+ .count_func = event_trigger_count,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
};
static struct event_command trigger_hist_disable_cmd = {
.name = DISABLE_HIST_STR,
.trigger_type = ETT_HIST_ENABLE,
- .trigger_ops = &hist_disable_trigger_ops,
.parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.unreg_all = hist_enable_unreg_all,
.set_filter = set_trigger_filter,
+ .trigger = hist_enable_trigger,
+ .count_func = event_trigger_count,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
};
static __init void unregister_trigger_hist_enable_disable_cmds(void)
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 41122a81e7966..4ee3d602a22e3 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -35,14 +35,14 @@ static inline void data_ops_trigger(struct event_trigger_data *data,
struct trace_buffer *buffer, void *rec,
struct ring_buffer_event *event)
{
- const struct event_trigger_ops *ops = data->ops;
+ const struct event_command *cmd_ops = data->cmd_ops;
if (data->flags & EVENT_TRIGGER_FL_COUNT) {
- if (!ops->count_func(data, buffer, rec, event))
+ if (!cmd_ops->count_func(data, buffer, rec, event))
return;
}
- ops->trigger(data, buffer, rec, event);
+ cmd_ops->trigger(data, buffer, rec, event);
}
/**
@@ -208,7 +208,7 @@ static int trigger_show(struct seq_file *m, void *v)
}
data = list_entry(v, struct event_trigger_data, list);
- data->ops->print(m, data);
+ data->cmd_ops->print(m, data);
return 0;
}
@@ -446,7 +446,7 @@ bool event_trigger_count(struct event_trigger_data *data,
}
/**
- * event_trigger_print - Generic event_trigger_ops @print implementation
+ * event_trigger_print - Generic event_command @print implementation
* @name: The name of the event trigger
* @m: The seq_file being printed to
* @data: Trigger-specific data
@@ -481,7 +481,7 @@ event_trigger_print(const char *name, struct seq_file *m,
}
/**
- * event_trigger_init - Generic event_trigger_ops @init implementation
+ * event_trigger_init - Generic event_command @init implementation
* @data: Trigger-specific data
*
* Common implementation of event trigger initialization.
@@ -498,7 +498,7 @@ int event_trigger_init(struct event_trigger_data *data)
}
/**
- * event_trigger_free - Generic event_trigger_ops @free implementation
+ * event_trigger_free - Generic event_command @free implementation
* @data: Trigger-specific data
*
* Common implementation of event trigger de-initialization.
@@ -560,8 +560,8 @@ clear_event_triggers(struct trace_array *tr)
list_for_each_entry_safe(data, n, &file->triggers, list) {
trace_event_trigger_enable_disable(file, 0);
list_del_rcu(&data->list);
- if (data->ops->free)
- data->ops->free(data);
+ if (data->cmd_ops->free)
+ data->cmd_ops->free(data);
}
}
}
@@ -626,8 +626,8 @@ static int register_trigger(char *glob,
}
}
- if (data->ops->init) {
- ret = data->ops->init(data);
+ if (data->cmd_ops->init) {
+ ret = data->cmd_ops->init(data);
if (ret < 0)
goto out;
}
@@ -666,8 +666,8 @@ static bool try_unregister_trigger(char *glob,
}
if (data) {
- if (data->ops->free)
- data->ops->free(data);
+ if (data->cmd_ops->free)
+ data->cmd_ops->free(data);
return true;
}
@@ -903,10 +903,9 @@ struct event_trigger_data *trigger_data_alloc(struct event_command *cmd_ops,
return NULL;
trigger_data->count = -1;
- trigger_data->ops = cmd_ops->trigger_ops;
trigger_data->cmd_ops = cmd_ops;
trigger_data->private_data = private_data;
- if (param && cmd_ops->trigger_ops->count_func)
+ if (param && cmd_ops->count_func)
trigger_data->flags |= EVENT_TRIGGER_FL_COUNT;
INIT_LIST_HEAD(&trigger_data->list);
@@ -1432,41 +1431,33 @@ traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data)
data->filter_str);
}
-static const struct event_trigger_ops traceon_trigger_ops = {
- .trigger = traceon_trigger,
- .count_func = traceon_count_func,
- .print = traceon_trigger_print,
- .init = event_trigger_init,
- .free = event_trigger_free,
-};
-
-static const struct event_trigger_ops traceoff_trigger_ops = {
- .trigger = traceoff_trigger,
- .count_func = traceoff_count_func,
- .print = traceoff_trigger_print,
- .init = event_trigger_init,
- .free = event_trigger_free,
-};
-
static struct event_command trigger_traceon_cmd = {
.name = "traceon",
.trigger_type = ETT_TRACE_ONOFF,
- .trigger_ops = &traceon_trigger_ops,
.parse = event_trigger_parse,
.reg = register_trigger,
.unreg = unregister_trigger,
.set_filter = set_trigger_filter,
+ .trigger = traceon_trigger,
+ .count_func = traceon_count_func,
+ .print = traceon_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
};
static struct event_command trigger_traceoff_cmd = {
.name = "traceoff",
.trigger_type = ETT_TRACE_ONOFF,
.flags = EVENT_CMD_FL_POST_TRIGGER,
- .trigger_ops = &traceoff_trigger_ops,
.parse = event_trigger_parse,
.reg = register_trigger,
.unreg = unregister_trigger,
.set_filter = set_trigger_filter,
+ .trigger = traceoff_trigger,
+ .count_func = traceoff_count_func,
+ .print = traceoff_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
};
#ifdef CONFIG_TRACER_SNAPSHOT
@@ -1514,22 +1505,18 @@ snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data)
data->filter_str);
}
-static const struct event_trigger_ops snapshot_trigger_ops = {
- .trigger = snapshot_trigger,
- .count_func = event_trigger_count,
- .print = snapshot_trigger_print,
- .init = event_trigger_init,
- .free = event_trigger_free,
-};
-
static struct event_command trigger_snapshot_cmd = {
.name = "snapshot",
.trigger_type = ETT_SNAPSHOT,
- .trigger_ops = &snapshot_trigger_ops,
.parse = event_trigger_parse,
.reg = register_snapshot_trigger,
.unreg = unregister_snapshot_trigger,
.set_filter = set_trigger_filter,
+ .trigger = snapshot_trigger,
+ .count_func = event_trigger_count,
+ .print = snapshot_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
};
static __init int register_trigger_snapshot_cmd(void)
@@ -1583,23 +1570,19 @@ stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data)
data->filter_str);
}
-static const struct event_trigger_ops stacktrace_trigger_ops = {
- .trigger = stacktrace_trigger,
- .count_func = event_trigger_count,
- .print = stacktrace_trigger_print,
- .init = event_trigger_init,
- .free = event_trigger_free,
-};
-
static struct event_command trigger_stacktrace_cmd = {
.name = "stacktrace",
.trigger_type = ETT_STACKTRACE,
- .trigger_ops = &stacktrace_trigger_ops,
.flags = EVENT_CMD_FL_POST_TRIGGER,
.parse = event_trigger_parse,
.reg = register_trigger,
.unreg = unregister_trigger,
.set_filter = set_trigger_filter,
+ .trigger = stacktrace_trigger,
+ .count_func = event_trigger_count,
+ .print = stacktrace_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
};
static __init int register_trigger_stacktrace_cmd(void)
@@ -1696,22 +1679,6 @@ void event_enable_trigger_free(struct event_trigger_data *data)
}
}
-static const struct event_trigger_ops event_enable_trigger_ops = {
- .trigger = event_enable_trigger,
- .count_func = event_enable_count_func,
- .print = event_enable_trigger_print,
- .init = event_trigger_init,
- .free = event_enable_trigger_free,
-};
-
-static const struct event_trigger_ops event_disable_trigger_ops = {
- .trigger = event_enable_trigger,
- .count_func = event_enable_count_func,
- .print = event_enable_trigger_print,
- .init = event_trigger_init,
- .free = event_enable_trigger_free,
-};
-
int event_enable_trigger_parse(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob, char *cmd, char *param_and_filter)
@@ -1843,8 +1810,8 @@ int event_enable_register_trigger(char *glob,
}
}
- if (data->ops->init) {
- ret = data->ops->init(data);
+ if (data->cmd_ops->init) {
+ ret = data->cmd_ops->init(data);
if (ret < 0)
goto out;
}
@@ -1885,28 +1852,36 @@ void event_enable_unregister_trigger(char *glob,
}
}
- if (data && data->ops->free)
- data->ops->free(data);
+ if (data && data->cmd_ops->free)
+ data->cmd_ops->free(data);
}
static struct event_command trigger_enable_cmd = {
.name = ENABLE_EVENT_STR,
.trigger_type = ETT_EVENT_ENABLE,
- .trigger_ops = &event_enable_trigger_ops,
.parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.set_filter = set_trigger_filter,
+ .trigger = event_enable_trigger,
+ .count_func = event_enable_count_func,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
};
static struct event_command trigger_disable_cmd = {
.name = DISABLE_EVENT_STR,
.trigger_type = ETT_EVENT_ENABLE,
- .trigger_ops = &event_disable_trigger_ops,
.parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.set_filter = set_trigger_filter,
+ .trigger = event_enable_trigger,
+ .count_func = event_enable_count_func,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
};
static __init void unregister_trigger_enable_disable_cmds(void)
--
2.53.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 6.12.y 4/4] tracing: Take the reference before publishing the named histogram trigger
2026-09-16 19:03 ` [PATCH 6.12.y 1/4] tracing: Constify struct event_trigger_ops Sasha Levin
2026-09-16 19:03 ` [PATCH 6.12.y 2/4] tracing: Remove get_trigger_ops() and add count_func() from trigger ops Sasha Levin
2026-09-16 19:03 ` [PATCH 6.12.y 3/4] tracing: Merge struct event_trigger_ops into struct event_command Sasha Levin
@ 2026-09-16 19:03 ` Sasha Levin
2 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2026-09-16 19:03 UTC (permalink / raw)
To: stable; +Cc: Donggeun Yoo, Sashiko AI, Tom Zanussi, Steven Rostedt,
Sasha Levin
From: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
[ Upstream commit 0fe23b8eaba0d3372c66b7b31204408da0715edc ]
event_hist_trigger_named_init() puts the trigger on the global
named_triggers list and only then takes the reference on the trigger it
shares its histogram with:
data->ref++;
save_named_trigger(data->named_data->name, data);
ret = event_hist_trigger_init(data->named_data);
if (ret < 0) {
kfree(data->cmd_ops);
data->cmd_ops = &trigger_hist_cmd;
}
return ret;
event_hist_trigger_init() fails when alloc_hist_pad() cannot allocate, and
nothing takes the trigger back off the list on the way out.
event_hist_trigger_parse() frees it, and the next lookup by name reads the
freed object:
BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0
Read of size 8 at addr ffff888009346860 by task init/1
find_named_trigger+0xac/0xc0
hist_register_trigger+0xc1/0xa00
event_hist_trigger_parse+0x3146/0x6af0
event_trigger_write+0xce/0x160
Freed by task 67:
kfree+0x154/0x420
trigger_kthread_fn+0xfd/0x160
Do the reference first and publish once it has succeeded, so that nothing
which can fail runs after the trigger becomes findable.
Cc: stable@vger.kernel.org
Fixes: 7ab0fc61ce73 ("tracing: Move histogram trigger variables from stack to per CPU structure")
Reported-by: Sashiko AI <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/linux-trace-kernel/20260907092944.3950E1F00A3D@smtp.kernel.org/
Link: https://patch.msgid.link/20260907124420.607097-2-donggeunyoo.kernel@gmail.com
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Acked-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/trace/trace_events_hist.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 7b0fc0bb62f0b..fde1aad3ee539 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -6330,17 +6330,18 @@ static int event_hist_trigger_named_init(struct event_trigger_data *data)
{
int ret;
- data->ref++;
-
- save_named_trigger(data->named_data->name, data);
-
ret = event_hist_trigger_init(data->named_data);
if (ret < 0) {
kfree(data->cmd_ops);
data->cmd_ops = &trigger_hist_cmd;
+ return ret;
}
- return ret;
+ data->ref++;
+
+ save_named_trigger(data->named_data->name, data);
+
+ return 0;
}
static void event_hist_trigger_named_free(struct event_trigger_data *data)
--
2.53.0
^ permalink raw reply related [flat|nested] 5+ messages in thread