Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932327Ab3ICDw5 (ORCPT ); Mon, 2 Sep 2013 23:52:57 -0400 Received: from mga14.intel.com ([143.182.124.37]:9807 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759365Ab3ICDwp (ORCPT ); Mon, 2 Sep 2013 23:52:45 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.89,1011,1367996400"; d="scan'208";a="355054751" From: Tom Zanussi To: rostedt@goodmis.org Cc: masami.hiramatsu.pt@hitachi.com, linux-kernel@vger.kernel.org, Tom Zanussi Subject: [PATCH v8 05/10] tracing: Add 'stacktrace' event trigger command Date: Mon, 2 Sep 2013 22:52:21 -0500 Message-Id: X-Mailer: git-send-email 1.7.11.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4167 Lines: 140 Add 'stacktrace' event_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 --- include/linux/ftrace_event.h | 1 + kernel/trace/trace_events_trigger.c | 76 +++++++++++++++++++++++++++++++++++++ 2 files changed, 77 insertions(+) diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 40b517b..31750df 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 9bdcc38..36b6601 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -732,6 +732,71 @@ 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(struct event_trigger_data *data) +{ + trace_dump_stack(STACK_SKIP); +} + +static void +stacktrace_count_trigger(struct event_trigger_data *data) +{ + 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, + struct event_trigger_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, @@ -776,5 +841,16 @@ __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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/