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    SubjectRe: [kernel-hardening] [PATCH 0/2] introduce post-init read-only memory

    * Andy Lutomirski <luto@amacapital.net> wrote:

    > >> - print a warning and a backtrace, and just mark the page read-write
    > >> so that the machine survives, but we get notified and can fix whatever
    > >> broken code
    > >
    > > This seems very easy to add. Should I basically reverse the effects of
    > > mark_rodata_ro(), or should I only make the new ro-after-init section as RW?
    > > (I think the former would be easier.)
    >
    > I'd suggest verifying that the page in question is .data..ro_after_init and, if
    > so, marking that one page RW.

    Yes, this was PaX's suggestion as well, and I agree: doing that turns a quite
    possibly unrecoverable boot/shutdown time or suspend/resume time (suspend is
    really a special category of 'bootup') crasher oops into a more informative stack
    dump.

    These ro related faults tend to trigger when init/deinit is running, and oopsing
    in those sequences is typically a lot less survivable than say oopsing in a high
    level system call while not holding locks.

    Thanks,

    Ingo


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