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    Subject[PATCH v2 2/7] watchdog: Explicitly update timestamp when reporting softlockup
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    The softlockup situation might stay for a long time or even forever.
    When it happens, the softlockup debug messages are printed in regular
    intervals defined by get_softlockup_thresh().

    There is a mystery. The repeated message is printed after the full interval
    that is defined by get_softlockup_thresh(). But the timer callback is called
    more often as defined by sample_period. The code looks like the soflockup
    should get reported in every sample_period when it was once behind the thresh.

    It works only by chance. The watchdog is touched when printing the stall
    report, for example, in printk_stack_address().

    Make the behavior clear and predictable by explicitly updating
    the timestamp in watchdog_timer_fn() when the report gets printed.

    Signed-off-by: Petr Mladek <pmladek@suse.com>
    ---
    kernel/watchdog.c | 3 +++
    1 file changed, 3 insertions(+)

    diff --git a/kernel/watchdog.c b/kernel/watchdog.c
    index c58244064de8..7776d53a015c 100644
    --- a/kernel/watchdog.c
    +++ b/kernel/watchdog.c
    @@ -409,6 +409,9 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
    }
    }

    + /* Start period for the next softlockup warning. */
    + update_touch_ts();
    +
    pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
    smp_processor_id(), duration,
    current->comm, task_pid_nr(current));
    --
    2.26.2
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