linux-kernel - Re: [PATCH 3/5] ftrace: add ftrace

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Message-ID: <alpine.DEB.2.00.0903021252420.4771@gandalf.stny.rr.com>
Date:	Mon, 2 Mar 2009 12:53:24 -0500 (EST)
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Frédéric Weisbecker <fweisbec@...il.com>
cc:	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/5] ftrace: add ftrace_bprintk()


On Mon, 2 Mar 2009, Fr?d?ric Weisbecker wrote:
> >> +
> >> +static
> >> +void release_module_trace_bprintk_format(const char **start, const char **end)
> >> +{
> >> +     const char **iter;
> >> +     lock_btrace();
> >> +     for (iter = start; iter < end; iter++) {
> >> +             struct trace_bprintk_fmt *tb_fmt;
> >> +             if (!*iter)
> >> +                     continue;
> >> +
> >> +             tb_fmt = container_of(*iter, struct trace_bprintk_fmt, fmt[0]);
> >> +             tb_fmt->count--;
> >> +             if (!tb_fmt->count && !btrace_metadata_count) {
> >> +                     list_del(&tb_fmt->list);
> >> +                     kfree(tb_fmt);
> >
> > Shouldn't *iter get assigned to NULL somewhere here?
> >
> > -- Steve
> 
> 
> Hm, why?

Well, after we free tb_fmt, the *iter will then point to garbage. Right?

-- Steve