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Date: Thu, 26 Nov 2015 09:38:53 +0100
From: Jiri Olsa <jolsa@redhat.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>, Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        LKML <linux-kernel@vger.kernel.org>, David Ahern <dsahern@gmail.com>,
        Kan Liang <kan.liang@intel.com>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Andi Kleen <andi@firstfloor.org>, Wang Nan <wangnan0@huawei.com>
Subject: Re: [PATCH 1/3] perf top: Fix freeze on --call-graph flat/folded
Message-ID: <20151126083853.GA8822@krava.brq.redhat.com>
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On Thu, Nov 26, 2015 at 04:08:18PM +0900, Namhyung Kim wrote:
> The callchain rbtree is rebuilt periodically, so it needs to
> reinitialize the root everytime.  Otherwise it can be stuck in the
> rbtree insertion with stale pointers.
> 
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  tools/perf/util/callchain.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
> index fc3b1e0d09ee..564377d2bebf 100644
> --- a/tools/perf/util/callchain.c
> +++ b/tools/perf/util/callchain.c
> @@ -290,6 +290,7 @@ static void
>  sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
>  		u64 min_hit, struct callchain_param *param __maybe_unused)
>  {
> +	*rb_root = RB_ROOT;

it seems ok, but I did not find how this could be called twice?

the only sort I can see is done within:
  __hists__insert_output_entry

do we allow resorting of the callchains?

thanks,
jirka

>  	__sort_chain_flat(rb_root, &root->node, min_hit);
>  }
>  
> -- 
> 2.6.2
>