Re: [PATCH v2] perf: fix double free at function perf_hpp__reset_output_field

From	"Du, Changbin" <changbin.du@intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2] perf: fix double free at function perf_hpp__reset_output_field
Date	2017-04-11 12:20 +0200
Message-ID	<tv13Y-5FJ-5@gated-at.bofh.it> (permalink)
References	(5 earlier) <tuFPP-8ur-9@gated-at.bofh.it> <tuUlQ-1p3-7@gated-at.bofh.it> <tuYz7-3XH-3@gated-at.bofh.it> <tuZlw-4vi-7@gated-at.bofh.it> <tv13Y-5FJ-7@gated-at.bofh.it>
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> > >  
> > yes, this is an option. But for safety, I sugguest do not rely on list_del_init.
> > No rule rather than create one.
> > 
> > But anyway, both are ok for me. What's your options?
> 
> hum, also I dont think we need to touch that bit at all
> if we are going to remove it right away.. how about the
> change below?
> 
> jirka
> 
> 
> ---
> diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
> index 5d632dca672a..0ee7db43dd7d 100644
> --- a/tools/perf/ui/hist.c
> +++ b/tools/perf/ui/hist.c
> @@ -613,15 +613,15 @@ void perf_hpp__reset_output_field(struct perf_hpp_list *list)
>  
>  	/* reset output fields */
>  	perf_hpp_list__for_each_format_safe(list, fmt, tmp) {
> -		list_del_init(&fmt->list);
> -		list_del_init(&fmt->sort_list);
> +		list_del(&fmt->list);
> +		/* Remove the fmt from next loop processing. */
> +		list_del(&fmt->sort_list);
>  		fmt_free(fmt);
What if the fmt is not linked to sort_list? I see it is possible (please
checking perf_hpp__setup_output_field()). I am not sure if we really has
sunch case currently, just concern :)

>  	}
>  
>  	/* reset sort keys */
>  	perf_hpp_list__for_each_sort_list_safe(list, fmt, tmp) {
> -		list_del_init(&fmt->list);
> -		list_del_init(&fmt->sort_list);
> +		list_del(&fmt->sort_list);
>  		fmt_free(fmt);
>  	}
>  }

-- 
Thanks,
Changbin Du

Thread

Re: [PATCH v2] perf: fix double free at function  perf_hpp__reset_output_field "Du, Changbin" <changbin.du@intel.com> - 2017-04-11 05:10 +0200
  Re: [PATCH v2] perf: fix double free at function  perf_hpp__reset_output_field Jiri Olsa <jolsa@redhat.com> - 2017-04-11 09:40 +0200
    Re: [PATCH v2] perf: fix double free at function  perf_hpp__reset_output_field "Du, Changbin" <changbin.du@intel.com> - 2017-04-11 10:30 +0200
      Re: [PATCH v2] perf: fix double free at function  perf_hpp__reset_output_field "Du, Changbin" <changbin.du@intel.com> - 2017-04-11 12:20 +0200
        Re: [PATCH v2] perf: fix double free at function  perf_hpp__reset_output_field Jiri Olsa <jolsa@redhat.com> - 2017-04-11 12:40 +0200
          Re: [PATCH v2] perf: fix double free at function  perf_hpp__reset_output_field "Du, Changbin" <changbin.du@intel.com> - 2017-04-12 04:00 +0200
      Re: [PATCH v2] perf: fix double free at function  perf_hpp__reset_output_field Jiri Olsa <jolsa@redhat.com> - 2017-04-11 12:30 +0200

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