Date: Thu, 9 Feb 2012 12:48:45 -0200
From: Arnaldo Carvalho de Melo <acme@redhat.com>
To: Stephane Eranian <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@elte.hu
Subject: Re: [PATCH] perf: add sanity check on addr in
	symbol__inc_addr_samples()
Message-ID: <20120209144844.GA4998@infradead.org>
References: <20120209103016.GA1999@quad>
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Em Thu, Feb 09, 2012 at 11:30:16AM +0100, Stephane Eranian escreveu:
> 
> Check the value of addr against the bounds of the symbol.
> This is needed given we compute an offset:
>     	offset = addr - sym->start
>     
> And we don't want the offset to become negative.

I'll try and add a debug option to show the backtrace and values of
addr, sym, etc, so that we can fix the real problem.

I.e. this function shouldn't be receiving any such invalid addresses, as
the symbol lookup was done, the symbol was found to be this one, then
why it would be out of bounds at this point?!

- Arnaldo
     
> Signed-off-by: Stephane Eranian <eranian@google.com>
> 
> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> index 011ed26..8248d80 100644
> --- a/tools/perf/util/annotate.c
> +++ b/tools/perf/util/annotate.c
> @@ -64,7 +64,7 @@ int symbol__inc_addr_samples(struct symbol *sym, struct map *map,
>  
>  	pr_debug3("%s: addr=%#" PRIx64 "\n", __func__, map->unmap_ip(map, addr));
>  
> -	if (addr >= sym->end)
> +	if (addr >= sym->end || addr < sym->start)
>  		return 0;
>  
>  	offset = addr - sym->start;
--
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