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    SubjectRe: [PATCH v3] printk: use atomic updates for klogd work
    On (22/02/11 12:29), John Ogness wrote:
    > The per-cpu @printk_pending variable can be updated from
    > sleepable contexts, such as:
    >
    > get_random_bytes()
    > warn_unseeded_randomness()
    > printk_deferred()
    > defer_console_output()
    >
    > and can be updated from interrupt contexts, such as:
    >
    > handle_irq_event_percpu()
    > __irq_wake_thread()
    > wake_up_process()
    > try_to_wake_up()
    > select_task_rq()
    > select_fallback_rq()
    > printk_deferred()
    > defer_console_output()
    >
    > and can be updated from NMI contexts, such as:
    >
    > vprintk()
    > if (in_nmi()) defer_console_output()
    >
    > Therefore the atomic variant of the updating functions must be used.
    >
    > Replace __this_cpu_xchg() with this_cpu_xchg().
    > Replace __this_cpu_or() with this_cpu_or().
    >
    > Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    > Signed-off-by: John Ogness <john.ogness@linutronix.de>

    FWIW
    Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>

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