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Date: Mon, 5 Mar 2012 15:35:35 -0800
From: Arun Sharma <asharma@fb.com>
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To: Arnaldo Carvalho de Melo <acme@redhat.com>
CC: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@elte.hu>,
        Stephane Eranian <eranian@google.com>, <linux-kernel@vger.kernel.org>,
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Subject: Re: [PATCH] perf report: auto-detect branch stack sampling mode
References: <20120224094048.GA7952@quad> <20120305154753.GA14604@elte.hu> <20120305155011.GA32413@elte.hu> <20120305155642.GB32413@elte.hu> <1330965033.11248.240.camel@twins> <20120305203518.GA5656@infradead.org> <4F55337B.4080807@fb.com> <20120305222614.GB5656@infradead.org>
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Like you probably figured from my other mail, we deal with deeply nested 
callchains with unwieldy function names a lot -- thanks to C++ and 
template programming. --tui's collapsing/expanding functionality is 
quite useful to navigate that mess. I'm just taking this opportunity to 
get some attention focused on improving it :)

On 3/5/12 2:26 PM, Arnaldo Carvalho de Melo wrote:

>> Here's an example:
>>
>> # perf record -ag -- sleep 3
>> # perf report -G -s pid --tui # SIGSEGV
>
> Ok, now this is a good report, I managed to reproduce and will work on a
> fix, thanks,

Something like this seems to do it for me.

         offset = addr - sym->start;
+       len = sym->end - sym->start;
+       if (offset >= len)
+               return 0;
+

The other problem area seems to be callchains when using -p regexp -x 
options. I'll try to summarize problems there in a separate thread.

  -Arun