Messages in this thread Patch in this message | | | Date | Tue, 11 Apr 2017 12:05:31 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH v2] perf: fix double free at function perf_hpp__reset_output_field |
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On Tue, Apr 11, 2017 at 04:25:50PM +0800, Du, Changbin wrote: > > > (gdb) print fmt.sort_list > > > $5 = {next = 0x9727d0 <perf_hpp_list+16>, prev = 0x9727d0 <perf_hpp_list+16>} > > > > > > In this case, the fmt is linked in sort_list, but not in list. So crash > > > at the list_del_init(&fmt->list) of second loop. > > > > so the only place I can see the POISON could get there > > is in perf_hpp__column_unregister.. can't we just get > > rid of it like below > > > > jirka > > > > > > --- > > diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c > > index 5d632dca672a..7577effbf746 100644 > > --- a/tools/perf/ui/hist.c > > +++ b/tools/perf/ui/hist.c > > @@ -529,7 +529,7 @@ void perf_hpp_list__prepend_sort_field(struct perf_hpp_list *list, > > > > void perf_hpp__column_unregister(struct perf_hpp_fmt *format) > > { > > - list_del(&format->list); > > + list_del_init(&format->list); > > } > > > 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); } /* 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); } }
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