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    SubjectRe: [PATCH 0/4] coredump: core dump masking support v3
    Date
    Markus Gutschke <markus@google.com> wrote:

    > > How does it work when you can't actually get back to userspace to have
    > > userspace do the coredump? You still have to handle the userspace
    > > equivalents of double/triple faults.
    >
    > My experience shows that there are only very rare occurrences of situations
    > where you cannot get back into userspace to do the coredump, and the
    > coredumper tries very hard never to cause additional faults.

    So what? If they can occur, you have to handle them.

    > While I am sure you could construct scenarios where this would happen,
    > realistically the only one I have run into were stack overflows, and they can
    > be handled by carefully setting up an alternate stack for signal handlers --
    > just make sure the entire stack is already dirtied before you run out of
    > memory (or, turn of overcommitting).

    Duff SIGSEGV or SIGBUS signal handlers are just as realistic. All that takes
    is for someone to make a programming error. Remember: error paths are the
    least frequently tested.

    And any time you say "by carefully setting up" you can guarantee someone's
    going to do it wrong.

    David
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