linux-kernel - Re: [PATCH 2/8] perf, tools: Support handling complete branch stacks as histograms v4

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Date:	Wed, 5 Mar 2014 11:29:48 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	acme@...hat.com, mingo@...nel.org, linux-kernel@...r.kernel.org,
	eranian@...gle.com, namhyung@...nel.org,
	Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH 2/8] perf, tools: Support handling complete branch stacks
 as histograms v4

On Thu, Feb 27, 2014 at 08:22:26PM -0800, Andi Kleen wrote:
> From: Andi Kleen <ak@...ux.intel.com>
> 

SNIP

> +
>  static int machine__resolve_callchain_sample(struct machine *machine,
>  					     struct thread *thread,
>  					     struct ip_callchain *chain,
> +					     struct branch_stack *branch,
>  					     struct symbol **parent,
>  					     struct addr_location *root_al,
>  					     int max_stack)
> @@ -1283,17 +1365,73 @@ static int machine__resolve_callchain_sample(struct machine *machine,
>  	int chain_nr = min(max_stack, (int)chain->nr);
>  	int i;
>  	int err;
> +	int first_call = 0;
>  
>  	callchain_cursor_reset(&callchain_cursor);
>  
> +	/*
> +	 * Add branches to call stack for easier browsing. This gives
> +	 * more context for a sample than just the callers.
> +	 *
> +	 * This uses individual histograms of paths compared to the
> +	 * aggregated histograms the normal LBR mode uses.
> +	 *
> +	 * Limitations for now:
> +	 * - No extra filters
> +	 * - No annotations (should annotate somehow)
> +	 */
> +
> +	if (branch->nr > PERF_MAX_BRANCH_DEPTH) {
> +		pr_warning("corrupted branch chain. skipping...\n");
> +		return 0;
> +	}

segfaults here..

[jolsa@...va perf]$ ./perf record -g sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.013 MB perf.data (~567 samples) ]
[jolsa@...va perf]$ ./perf report
perf: Segmentation fault
[jolsa@...va perf]$ 

jirka
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