linux-kernel - Re: [PATCH v2] Re: perf annotate segfaults when source code has goto label that looks like hex number

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Date:	Thu, 22 Jul 2010 21:05:38 +0300
From:	Gleb Natapov <gleb@...hat.com>
To:	Arnaldo Carvalho de Melo <acme@...radead.org>
Cc:	linux-kernel@...r.kernel.org, mingo@...e.hu, peterz@...radead.org,
	paulus@...ba.org
Subject: Re: [PATCH v2] Re: perf annotate segfaults when source code has
 goto label that looks like hex number

On Thu, Jul 22, 2010 at 02:05:42PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Thu, Jul 22, 2010 at 01:52:22PM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Thu, Jul 22, 2010 at 01:47:11PM -0300, Arnaldo Carvalho de Melo escreveu:
> > > Em Thu, Jul 22, 2010 at 07:38:51PM +0300, Gleb Natapov escreveu:
> > > > On Thu, Jul 22, 2010 at 11:33:45AM -0300, Arnaldo Carvalho de Melo wrote:
> > > > > Can you try the attached patch?
> > > > > 
> > > > I can, only later. But if I underhand your patch correctly perf will
> > > > still crash if there is a comment after the label on the same line.
> > > 
> > > Possibly, will try that now.
> > 
> > It could be a comment of play code, like:
> > 
> > [root@...lia ~]# cat test.c 
> > int main(int argc, char **argv)
> > {
> >       int i;
> > 
> >       while(1) {
> >               i++;
> >               if (i == 10000000)
> >                       goto add;
> >       }
> > add:	return 0;
> > }
> > [root@...lia ~]#
> > 
> > back to the drawing board :-\
> 
> What about this one?
> 
> diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
> index 699cf81..96e9044 100644
> --- a/tools/perf/util/hist.c
> +++ b/tools/perf/util/hist.c
> @@ -976,13 +976,15 @@ static int hist_entry__parse_objdump_line(struct hist_entry *self, FILE *file,
>  		 * Parse hexa addresses followed by ':'
>  		 */
>  		line_ip = strtoull(tmp, &tmp2, 16);
> -		if (*tmp2 != ':' || tmp == tmp2)
> +		if (*tmp2 != ':' || tmp == tmp2 || tmp2[1] == '\0')
>  			line_ip = -1;
>  	}
>  
>  	if (line_ip != -1) {
>  		u64 start = map__rip_2objdump(self->ms.map, sym->start);
>  		offset = line_ip - start;
> +		if (offset < 0 || (u64)line_ip > sym->end)
> +			offset = -1;
>  	}
>  
This part is good idea anyway. Even if label will be interpreted as ip
perf at least will not crash. It may miss-report something if check will
accidentally succeed though.

>  	objdump_line = objdump_line__new(offset, line);

--
			Gleb.
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