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    SubjectRe: [PATCH] mm: sync rss-counters at the end of exit_mm()
    On 2012.04.10 at 10:34 +0400, Konstantin Khlebnikov wrote:
    > Hugh Dickins wrote:
    > > On Mon, 9 Apr 2012, KOSAKI Motohiro wrote:
    > >> On Mon, Apr 9, 2012 at 4:03 PM, Konstantin Khlebnikov
    > >> <khlebnikov@openvz.org> wrote:
    > >>> On task's exit do_exit() calls sync_mm_rss() but this is not enough,
    > >>> there can be page-faults after this point, for example exit_mm() ->
    > >>> mm_release() -> put_user() (for processing tsk->clear_child_tid).
    > >>> Thus there may be some rss-counters delta in current->rss_stat.
    > >>
    > >> Seems reasonable.
    > >
    > > Yes, I think Konstantin has probably caught it;
    > > but I'd like to hear confirmation from Markus.
    >
    > There is another bug in exec_mmap()
    >
    > --- a/fs/exec.c
    > +++ b/fs/exec.c
    > @@ -823,8 +823,8 @@ static int exec_mmap(struct mm_struct *mm)
    > /* Notify parent that we're no longer interested in the old VM */
    > tsk = current;
    > old_mm = current->mm;
    > - sync_mm_rss(old_mm);
    > mm_release(tsk, old_mm);
    > + sync_mm_rss(old_mm);
    >
    > if (old_mm) {
    > /*

    FWIW with both patches applied I cannot reproduce the issue anymore.

    Thanks.

    --
    Markus


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