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SubjectRe: [PATCH 1/3] [BUGFIX] tracing: Fix double free of event_trigger_data
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>

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