Messages in this thread Patch in this message | | | From | Tom Zanussi <> | Subject | [PATCH v7 05/10] tracing: add 'stacktrace' event trigger command | Date | Tue, 27 Aug 2013 14:40:17 -0500 |
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Add 'stacktrace' ftrace_func_command. stacktrace event triggers are added by the user via this command in a similar way and using practically the same syntax as the analogous 'stacktrace' ftrace function command, but instead of writing to the set_ftrace_filter file, the stacktrace event trigger is written to the per-event 'trigger' files:
echo 'stacktrace' > .../tracing/events/somesys/someevent/trigger
The above command will turn on stacktraces for someevent i.e. whenever someevent is hit, a stacktrace will be logged.
This also adds a 'count' version that limits the number of times the command will be invoked:
echo 'stacktrace:N' > .../tracing/events/somesys/someevent/trigger
Where N is the number of times the command will be invoked.
The above command will log N stacktraces for someevent i.e. whenever someevent is hit N times, a stacktrace will be logged.
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> --- include/linux/ftrace_event.h | 1 + kernel/trace/trace_events_trigger.c | 90 +++++++++++++++++++++++++++++++++++++ 2 files changed, 91 insertions(+)
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 21fae3d..df5eae9 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -320,6 +320,7 @@ enum event_trigger_type { ETT_NONE = (0), ETT_TRACE_ONOFF = (1 << 0), ETT_SNAPSHOT = (1 << 1), + ETT_STACKTRACE = (1 << 2), }; extern void destroy_preds(struct ftrace_event_call *call); diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 1c266f9..c83f56f 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -790,6 +790,85 @@ static struct event_command trigger_snapshot_cmd = { .get_trigger_ops = snapshot_get_trigger_ops, }; +/* + * Skip 4: + * ftrace_stacktrace() + * function_trace_probe_call() + * ftrace_ops_list_func() + * ftrace_call() + */ +#define STACK_SKIP 4 + +static void +stacktrace_trigger(void **_data) +{ + struct event_trigger_data **p = (struct event_trigger_data **)_data; + struct event_trigger_data *data = *p; + + if (!data) + return; + + trace_dump_stack(STACK_SKIP); +} + +static void +stacktrace_count_trigger(void **_data) +{ + struct event_trigger_data **p = (struct event_trigger_data **)_data; + struct event_trigger_data *data = *p; + + if (!data) + return; + + if (!data->count) + return; + + if (data->count != -1) + (data->count)--; + + stacktrace_trigger(_data); +} + +static int +stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops, + void *_data) +{ + struct event_trigger_data *data = _data; + + return event_trigger_print("stacktrace", m, (void *)data->count, + data->filter_str); +} + +static struct event_trigger_ops stacktrace_trigger_ops = { + .func = stacktrace_trigger, + .print = stacktrace_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops stacktrace_count_trigger_ops = { + .func = stacktrace_count_trigger, + .print = stacktrace_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static 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, + .post_trigger = true, + .func = event_trigger_callback, + .reg = register_trigger, + .unreg = unregister_trigger, + .get_trigger_ops = stacktrace_get_trigger_ops, +}; + static __init void unregister_trigger_traceon_traceoff_cmds(void) { unregister_event_command(&trigger_traceon_cmd, @@ -834,5 +913,16 @@ __init int register_trigger_cmds(void) return ret; } + ret = register_event_command(&trigger_stacktrace_cmd, + &trigger_commands, + &trigger_cmd_mutex); + if (WARN_ON(ret < 0)) { + unregister_trigger_traceon_traceoff_cmds(); + unregister_event_command(&trigger_snapshot_cmd, + &trigger_commands, + &trigger_cmd_mutex); + return ret; + } + return 0; } -- 1.7.11.4
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