lkml.org 
[lkml]   [2017]   [Apr]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH v2] perf: fix double free at function perf_hpp__reset_output_field
    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);
    }
    }
    \
     
     \ /
      Last update: 2017-04-11 12:21    [W:3.714 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site