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    SubjectRe: new text patching for review
    Mathieu Desnoyers wrote:
    > Yes, kprobes is case 1: atomic update. And we don't even have to bother
    > about Intel's erratum. This one is ok. That's mainly the
    > alternatives/paravirt code I worry about.
    >

    Paravirt and alternatives should all be ok because they are done before
    SMP bringup and with NMIs disabled. NMI watchdog is not setup until
    smp_prepare_cpus/check_nmi_watchdog, which happens way later, not during
    parse_args/setup_nmi_watchdog, which just decides which type of watchdog
    to setup.

    I originally considered the NMI problem for paravirt-ops patching done
    during module load, and found that I would need to modify
    stop_machine_run to have an architecture specific callout to mask and
    unmask NMIs. I didn't imagine that would be very popular, and VMI was
    the only paravirt-ops that were considering module load time patching,
    so I flushed it.

    You get some other nasty issues as well with run-time switching, like
    missing early init calls (in particular, we would have to go to some
    heroics to retake the land surrounding the APIC local timer interrupt).

    Zach
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