From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756783AbbJ2JLf (ORCPT ); Thu, 29 Oct 2015 05:11:35 -0400 Received: from LGEAMRELO13.lge.com ([156.147.23.53]:46021 "EHLO lgeamrelo13.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755515AbbJ2JLb (ORCPT ); Thu, 29 Oct 2015 05:11:31 -0400 X-Original-SENDERIP: 156.147.1.151 X-Original-MAILFROM: namhyung@kernel.org X-Original-SENDERIP: 165.244.98.203 X-Original-MAILFROM: namhyung@kernel.org X-Original-SENDERIP: 10.177.227.17 X-Original-MAILFROM: namhyung@kernel.org Date: Thu, 29 Oct 2015 18:11:29 +0900 From: Namhyung Kim To: Tom Zanussi CC: rostedt@goodmis.org, daniel.wagner@bmw-carit.de, masami.hiramatsu.pt@hitachi.com, josh@joshtriplett.org, andi@firstfloor.org, mathieu.desnoyers@efficios.com, peterz@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v11 09/28] tracing: Add 'hist' event trigger command Message-ID: <20151029091129.GB2617@sejong> References: <0ccd6f1613dc5a8159fc900b5128e3840ad599f3.1445530672.git.tom.zanussi@linux.intel.com> MIME-Version: 1.0 In-Reply-To: <0ccd6f1613dc5a8159fc900b5128e3840ad599f3.1445530672.git.tom.zanussi@linux.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-MIMETrack: Itemize by SMTP Server on LGEKRMHUB05/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2015/10/29 18:11:29, Serialize by Router on LGEKRMHUB05/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2015/10/29 18:11:29, Serialize complete at 2015/10/29 18:11:29 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 22, 2015 at 01:14:13PM -0500, Tom Zanussi wrote: > 'hist' triggers allow users to continually aggregate trace events, > which can then be viewed afterwards by simply reading a 'hist' file > containing the aggregation in a human-readable format. > > The basic idea is very simple and boils down to a mechanism whereby > trace events, rather than being exhaustively dumped in raw form and > viewed directly, are automatically 'compressed' into meaningful tables > completely defined by the user. > > This is done strictly via single-line command-line commands and > without the aid of any kind of programming language or interpreter. > > A surprising number of typical use cases can be accomplished by users > via this simple mechanism. In fact, a large number of the tasks that > users typically do using the more complicated script-based tracing > tools, at least during the initial stages of an investigation, can be > accomplished by simply specifying a set of keys and values to be used > in the creation of a hash table. > > The Linux kernel trace event subsystem happens to provide an extensive > list of keys and values ready-made for such a purpose in the form of > the event format files associated with each trace event. By simply > consulting the format file for field names of interest and by plugging > them into the hist trigger command, users can create an endless number > of useful aggregations to help with investigating various properties > of the system. See Documentation/trace/events.txt for examples. > > hist triggers are implemented on top of the existing event trigger > infrastructure, and as such are consistent with the existing triggers > from a user's perspective as well. > > The basic syntax follows the existing trigger syntax. Users start an > aggregation by writing a 'hist' trigger to the event of interest's > trigger file: > > # echo hist:keys=xxx [ if filter] > event/trigger > > Once a hist trigger has been set up, by default it continually > aggregates every matching event into a hash table using the event key > and a value field named 'hitcount'. > > To view the aggregation at any point in time, simply read the 'hist' > file in the same directory as the 'trigger' file: > > # cat event/hist > > The detailed syntax provides additional options for user control, and > is described exhaustively in Documentation/trace/events.txt and in the > virtual tracing/README file in the tracing subsystem. > > Signed-off-by: Tom Zanussi > Tested-by: Masami Hiramatsu > --- [SNIP] > +static int event_hist_trigger_func(struct event_command *cmd_ops, > + struct trace_event_file *file, > + char *glob, char *cmd, char *param) > +{ > + unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT; > + struct event_trigger_data *trigger_data; > + struct hist_trigger_attrs *attrs; > + struct event_trigger_ops *trigger_ops; > + struct hist_trigger_data *hist_data; > + char *trigger; > + int ret = 0; > + > + if (!param) > + return -EINVAL; > + > + /* separate the trigger from the filter (k:v [if filter]) */ > + trigger = strsep(¶m, " \t"); > + if (!trigger) > + return -EINVAL; > + > + attrs = parse_hist_trigger_attrs(trigger); > + if (IS_ERR(attrs)) > + return PTR_ERR(attrs); > + > + if (!attrs->keys_str) > + return -EINVAL; Wouldn't it leak the attrs? > + > + if (attrs->map_bits) > + hist_trigger_bits = attrs->map_bits; > + > + hist_data = create_hist_data(hist_trigger_bits, attrs, file); > + if (IS_ERR(hist_data)) > + return PTR_ERR(hist_data); It also can leak the attrs IMHO. > + > + trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger); > + > + ret = -ENOMEM; > + trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL); > + if (!trigger_data) > + goto out; Here, the hist_data and the attr can be leaked. Thanks, Namhyung > + > + trigger_data->count = -1; > + trigger_data->ops = trigger_ops; > + trigger_data->cmd_ops = cmd_ops; > + > + INIT_LIST_HEAD(&trigger_data->list); > + RCU_INIT_POINTER(trigger_data->filter, NULL); > + > + trigger_data->private_data = hist_data; > + > + if (glob[0] == '!') { > + cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file); > + ret = 0; > + goto out_free; > + } > + > + if (!param) /* if param is non-empty, it's supposed to be a filter */ > + goto out_reg; > + > + if (!cmd_ops->set_filter) > + goto out_reg; > + > + ret = cmd_ops->set_filter(param, trigger_data, file); > + if (ret < 0) > + goto out_free; > + out_reg: > + ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file); > + /* > + * The above returns on success the # of triggers registered, > + * but if it didn't register any it returns zero. Consider no > + * triggers registered a failure too. > + */ > + if (!ret) { > + ret = -ENOENT; > + goto out_free; > + } else if (ret < 0) > + goto out_free; > + /* Just return zero, not the number of registered triggers */ > + ret = 0; > + out: > + return ret; > + out_free: > + if (cmd_ops->set_filter) > + cmd_ops->set_filter(NULL, trigger_data, NULL); > + > + kfree(trigger_data); > + > + destroy_hist_data(hist_data); > + goto out; > +}