From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>, Shuah Khan <shuah@kernel.org>,
Hiraku Toyooka <hiraku.toyooka@cybertrust.co.jp>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 1/3] [BUGFIX] tracing: Fix double free of event_trigger_data
Date: Wed, 25 Jul 2018 23:14:02 +0900 [thread overview]
Message-ID: <20180725231402.1f9d8754cee6b35b7dee7b3c@kernel.org> (raw)
In-Reply-To: <20180724224149.0767fd13@gandalf.local.home>
On Tue, 24 Jul 2018 22:41:49 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Wed, 25 Jul 2018 10:16:53 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> > Hm, as far as I can see, when register_trigger() returns >= 0, it already
> > calls ->init the trigger_data. This means its refcount++, and in that
> > case, below patch will miss to free the trigger_data.
> > How about below for tentative fix?
> >
> > if (!ret) {
> > ret = -ENOENT;
> > /* We have to forcibly free the trigger_data */
> > goto out_free;
> > } else if (ret > 0)
> > ret = 0;
>
> Or better yet, match it properly:
OK, this looks good to me :)
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Thanks!
>
> out_reg:
> /* Up the trigger_data count to make sure reg doesn't free it on failure */
> event_trigger_init(trigger_ops, trigger_data);
> ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
> /*
> * The above returns on success the # of functions enabled,
> * but if it didn't find any functions it returns zero.
> * Consider no functions a failure too.
> */
> if (!ret) {
> cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
> ret = -ENOENT;
> } else if (ret > 0)
> ret = 0;
>
> /* Down the counter of trigger_data or free it if not used anymore */
> event_trigger_free(trigger_ops, trigger_data);
> out:
> return ret;
>
> -- Steve
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2018-07-25 14:14 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-13 16:27 [PATCH 0/3] tracing: Fix bugs on snapshot feature Masami Hiramatsu
2018-07-13 16:27 ` [PATCH 1/3] [BUGFIX] tracing: Fix double free of event_trigger_data Masami Hiramatsu
2018-07-24 2:10 ` Steven Rostedt
2018-07-24 15:09 ` Masami Hiramatsu
2018-07-24 20:49 ` Steven Rostedt
2018-07-24 21:30 ` Steven Rostedt
2018-07-24 23:13 ` Steven Rostedt
2018-07-25 1:16 ` Masami Hiramatsu
2018-07-25 2:41 ` Steven Rostedt
2018-07-25 14:14 ` Masami Hiramatsu [this message]
2018-07-25 16:01 ` Tom Zanussi
2018-07-25 16:09 ` Steven Rostedt
2018-07-25 1:05 ` Masami Hiramatsu
2018-07-13 16:28 ` [PATCH 2/3] [BUGFIX] ring_buffer: tracing: Inherit the tracing setting to next ring buffer Masami Hiramatsu
2018-07-24 2:25 ` Steven Rostedt
2018-07-24 14:30 ` Masami Hiramatsu
2018-07-13 16:28 ` [PATCH 3/3] selftests/ftrace: Add snapshot and tracing_on test case Masami Hiramatsu
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