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Date: Thu, 15 Oct 2009 17:47:54 +0800
Message-ID: <2375c9f90910150247u5ccb8e2at58c764e385ffa490@mail.gmail.com>
Subject: Re: [PATCH 3/4] tracing/profile: Add filter support
From: =?UTF-8?Q?Am=C3=A9rico_Wang?= <xiyou.wangcong@gmail.com>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <peterz@infradead.org>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       Steven Rostedt <rostedt@goodmis.org>, Tom Zanussi <tzanussi@gmail.com>,
       LKML <linux-kernel@vger.kernel.org>
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On Thu, Oct 15, 2009 at 11:21 AM, Li Zefan <lizf@cn.fujitsu.com> wrote:
> - Add an ioctl to allocate a filter for a perf event.
>
> - Free the filter when the associated perf event is to be freed.
>
> - Do the filtering in perf_swevent_match().
>
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

{snip}

> +int ftrace_profile_set_filter(struct perf_event *event, int event_id,
> +                             char *filter_str)
> +{
> +       int err;
> +       struct event_filter *filter;
> +       struct filter_parse_state *ps;
> +       struct ftrace_event_call *call = NULL;
> +
> +       mutex_lock(&event_mutex);
> +
> +       list_for_each_entry(call, &ftrace_events, list) {
> +               if (call->id == event_id)
> +                       break;
> +       }
> +       if (!call)
> +               return -EINVAL;
> +
> +       if (event->filter)
> +               return -EEXIST;
> +
> +       filter = __alloc_preds();
> +       if (IS_ERR(filter))
> +               return PTR_ERR(filter);


Just return will leave &event_mutex locked...

Am I missing something here?

> +
> +       err = -ENOMEM;
> +       ps = kzalloc(sizeof(*ps), GFP_KERNEL);
> +       if (!ps)
> +               goto free_preds;
> +
> +       parse_init(ps, filter_ops, filter_str);
> +       err = filter_parse(ps);
> +       if (err)
> +               goto free_ps;
> +
> +       err = replace_preds(call, filter, ps, filter_str, false);
> +       if (!err)
> +               event->filter = filter;
> +
> +free_ps:
> +       filter_opstack_clear(ps);
> +       postfix_clear(ps);
> +       kfree(ps);
> +
> +free_preds:
> +       if (err)
> +               __free_preds(filter);
> +
> +       mutex_unlock(&event_mutex);
> +
> +       return err;
> +}
> +