From: Ingo Molnar <mingo@elte.hu>
To: Zhaolei <zhaolei@cn.fujitsu.com>
Cc: "Steven Rostedt ;" <rostedt@goodmis.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ftrace: Avoid double-free of dyn_ftrace
Date: Fri, 13 Mar 2009 10:25:58 +0100 [thread overview]
Message-ID: <20090313092558.GD2571@elte.hu> (raw)
In-Reply-To: <49BA23D9.1050900@cn.fujitsu.com>
* Zhaolei <zhaolei@cn.fujitsu.com> wrote:
> If dyn_ftrace is free before ftrace_release(),
> ftrace_release() will free it again and make
> ftrace_free_records wrong.
>
> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
> ---
> kernel/trace/ftrace.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index d33d306..26c45aa 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -356,7 +356,8 @@ void ftrace_release(void *start, unsigned long size)
>
> mutex_lock(&ftrace_lock);
> do_for_each_ftrace_rec(pg, rec) {
> - if ((rec->ip >= s) && (rec->ip < e))
> + if ((rec->ip >= s) && (rec->ip < e) &&
> + !(rec->flags & FTRACE_FL_FREE))
> ftrace_free_rec(rec);
Applied to tip:tracing/ftrace, thanks!
I'm wondering, did you trigger this in practice (if yes, how?),
or have you found it via code review?
Ingo
next prev parent reply other threads:[~2009-03-13 9:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-13 9:14 [PATCH] ftrace: Avoid double-free of dyn_ftrace Zhaolei
2009-03-13 9:25 ` Ingo Molnar [this message]
2009-03-13 9:30 ` Zhaolei
2009-03-24 15:54 ` Steven Rostedt
2009-03-25 2:25 ` Zhaolei
2009-03-25 2:35 ` Steven Rostedt
2009-03-13 9:33 ` [tip:tracing/ftrace] ftrace: avoid " Zhaolei
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