diff options
Diffstat (limited to 'kernel/trace/trace_events_trigger.c')
| -rw-r--r-- | kernel/trace/trace_events_trigger.c | 170 |
1 files changed, 166 insertions, 4 deletions
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 45e48b109d51..f5b3f780fda4 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -31,6 +31,9 @@ static DEFINE_MUTEX(trigger_cmd_mutex); static void trigger_data_free(struct event_trigger_data *data) { + if (data->cmd_ops->set_filter) + data->cmd_ops->set_filter(NULL, data, NULL); + synchronize_sched(); /* make sure current triggers exit before free */ kfree(data); } @@ -38,27 +41,78 @@ trigger_data_free(struct event_trigger_data *data) /** * event_triggers_call - Call triggers associated with a trace event * @file: The ftrace_event_file associated with the event + * @rec: The trace entry for the event, NULL for unconditional invocation * * For each trigger associated with an event, invoke the trigger - * function registered with the associated trigger command. + * function registered with the associated trigger command. If rec is + * non-NULL, it means that the trigger requires further processing and + * shouldn't be unconditionally invoked. If rec is non-NULL and the + * trigger has a filter associated with it, rec will checked against + * the filter and if the record matches the trigger will be invoked. + * If the trigger is a 'post_trigger', meaning it shouldn't be invoked + * in any case until the current event is written, the trigger + * function isn't invoked but the bit associated with the deferred + * trigger is set in the return value. + * + * Returns an enum event_trigger_type value containing a set bit for + * any trigger that should be deferred, ETT_NONE if nothing to defer. * * Called from tracepoint handlers (with rcu_read_lock_sched() held). * * Return: an enum event_trigger_type value containing a set bit for * any trigger that should be deferred, ETT_NONE if nothing to defer. */ -void event_triggers_call(struct ftrace_event_file *file) +enum event_trigger_type +event_triggers_call(struct ftrace_event_file *file, void *rec) { struct event_trigger_data *data; + enum event_trigger_type tt = ETT_NONE; if (list_empty(&file->triggers)) - return; + return tt; - list_for_each_entry_rcu(data, &file->triggers, list) + list_for_each_entry_rcu(data, &file->triggers, list) { + if (!rec) { + data->ops->func(data); + continue; + } + if (data->filter && !filter_match_preds(data->filter, rec)) + continue; + if (data->cmd_ops->post_trigger) { + tt |= data->cmd_ops->trigger_type; + continue; + } data->ops->func(data); + } + return tt; } EXPORT_SYMBOL_GPL(event_triggers_call); +/** + * event_triggers_post_call - Call 'post_triggers' for a trace event + * @file: The ftrace_event_file associated with the event + * @tt: enum event_trigger_type containing a set bit for each trigger to invoke + * + * For each trigger associated with an event, invoke the trigger + * function registered with the associated trigger command, if the + * corresponding bit is set in the tt enum passed into this function. + * See @event_triggers_call for details on how those bits are set. + * + * Called from tracepoint handlers (with rcu_read_lock_sched() held). + */ +void +event_triggers_post_call(struct ftrace_event_file *file, + enum event_trigger_type tt) +{ + struct event_trigger_data *data; + + list_for_each_entry_rcu(data, &file->triggers, list) { + if (data->cmd_ops->trigger_type & tt) + data->ops->func(data); + } +} +EXPORT_SYMBOL_GPL(event_triggers_post_call); + static void *trigger_next(struct seq_file *m, void *t, loff_t *pos) { struct ftrace_event_file *event_file = event_file_data(m->private); @@ -403,6 +457,34 @@ clear_event_triggers(struct trace_array *tr) } /** + * update_cond_flag - Set or reset the TRIGGER_COND bit + * @file: The ftrace_event_file associated with the event + * + * If an event has triggers and any of those triggers has a filter or + * a post_trigger, trigger invocation needs to be deferred until after + * the current event has logged its data, and the event should have + * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be + * cleared. + */ +static void update_cond_flag(struct ftrace_event_file *file) +{ + struct event_trigger_data *data; + bool set_cond = false; + + list_for_each_entry_rcu(data, &file->triggers, list) { + if (data->filter || data->cmd_ops->post_trigger) { + set_cond = true; + break; + } + } + + if (set_cond) + set_bit(FTRACE_EVENT_FL_TRIGGER_COND_BIT, &file->flags); + else + clear_bit(FTRACE_EVENT_FL_TRIGGER_COND_BIT, &file->flags); +} + +/** * register_trigger - Generic event_command @reg implementation * @glob: The raw string used to register the trigger * @ops: The trigger ops associated with the trigger @@ -443,6 +525,7 @@ static int register_trigger(char *glob, struct event_trigger_ops *ops, list_del_rcu(&data->list); ret--; } + update_cond_flag(file); out: return ret; } @@ -470,6 +553,7 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops, if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) { unregistered = true; list_del_rcu(&data->list); + update_cond_flag(file); trace_event_trigger_enable_disable(file, 0); break; } @@ -572,10 +656,78 @@ event_trigger_callback(struct event_command *cmd_ops, return ret; out_free: + if (cmd_ops->set_filter) + cmd_ops->set_filter(NULL, trigger_data, NULL); kfree(trigger_data); goto out; } +/** + * set_trigger_filter - Generic event_command @set_filter implementation + * @filter_str: The filter string for the trigger, NULL to remove filter + * @trigger_data: Trigger-specific data + * @file: The ftrace_event_file associated with the event + * + * Common implementation for event command filter parsing and filter + * instantiation. + * + * Usually used directly as the @set_filter method in event command + * implementations. + * + * Also used to remove a filter (if filter_str = NULL). + * + * Return: 0 on success, errno otherwise + */ +static int set_trigger_filter(char *filter_str, + struct event_trigger_data *trigger_data, + struct ftrace_event_file *file) +{ + struct event_trigger_data *data = trigger_data; + struct event_filter *filter = NULL, *tmp; + int ret = -EINVAL; + char *s; + + if (!filter_str) /* clear the current filter */ + goto assign; + + s = strsep(&filter_str, " \t"); + + if (!strlen(s) || strcmp(s, "if") != 0) + goto out; + + if (!filter_str) + goto out; + + /* The filter is for the 'trigger' event, not the triggered event */ + ret = create_event_filter(file->event_call, filter_str, false, &filter); + if (ret) + goto out; + assign: + tmp = data->filter; + + rcu_assign_pointer(data->filter, filter); + + if (tmp) { + /* Make sure the call is done with the filter */ + synchronize_sched(); + free_event_filter(tmp); + } + + kfree(data->filter_str); + data->filter_str = NULL; + + if (filter_str) { + data->filter_str = kstrdup(filter_str, GFP_KERNEL); + if (!data->filter_str) { + free_event_filter(data->filter); + data->filter = NULL; + ret = -ENOMEM; + } + } + out: + return ret; +} + static void traceon_trigger(struct event_trigger_data *data) { @@ -685,6 +837,7 @@ static struct event_command trigger_traceon_cmd = { .reg = register_trigger, .unreg = unregister_trigger, .get_trigger_ops = onoff_get_trigger_ops, + .set_filter = set_trigger_filter, }; static struct event_command trigger_traceoff_cmd = { @@ -694,6 +847,7 @@ static struct event_command trigger_traceoff_cmd = { .reg = register_trigger, .unreg = unregister_trigger, .get_trigger_ops = onoff_get_trigger_ops, + .set_filter = set_trigger_filter, }; #ifdef CONFIG_TRACER_SNAPSHOT @@ -765,6 +919,7 @@ static struct event_command trigger_snapshot_cmd = { .reg = register_snapshot_trigger, .unreg = unregister_trigger, .get_trigger_ops = snapshot_get_trigger_ops, + .set_filter = set_trigger_filter, }; static __init int register_trigger_snapshot_cmd(void) @@ -843,6 +998,7 @@ static struct event_command trigger_stacktrace_cmd = { .reg = register_trigger, .unreg = unregister_trigger, .get_trigger_ops = stacktrace_get_trigger_ops, + .set_filter = set_trigger_filter, }; static __init int register_trigger_stacktrace_cmd(void) @@ -1100,6 +1256,8 @@ event_enable_trigger_func(struct event_command *cmd_ops, out_put: module_put(event_enable_file->event_call->mod); out_free: + if (cmd_ops->set_filter) + cmd_ops->set_filter(NULL, trigger_data, NULL); kfree(trigger_data); kfree(enable_data); goto out; @@ -1137,6 +1295,7 @@ static int event_enable_register_trigger(char *glob, list_del_rcu(&data->list); ret--; } + update_cond_flag(file); out: return ret; } @@ -1157,6 +1316,7 @@ static void event_enable_unregister_trigger(char *glob, (enable_data->file == test_enable_data->file)) { unregistered = true; list_del_rcu(&data->list); + update_cond_flag(file); trace_event_trigger_enable_disable(file, 0); break; } @@ -1191,6 +1351,7 @@ static struct event_command trigger_enable_cmd = { .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 = { @@ -1200,6 +1361,7 @@ static struct event_command trigger_disable_cmd = { .reg = event_enable_register_trigger, .unreg = event_enable_unregister_trigger, .get_trigger_ops = event_enable_get_trigger_ops, + .set_filter = set_trigger_filter, }; static __init void unregister_trigger_enable_disable_cmds(void) |
