On (04/04/17 11:01), Petr Mladek wrote:
[..]
> > +static atomic_t printk_emergency __read_mostly;
> > +/*
> > + * Disable printk_kthread permanently. Unlike `oops_in_progress'
> > + * it doesn't go back to 0.
> > + */
>
> The comment is not valid once we allow to modify the variable using
> the sysfs knob.
it's updated in that patch (sysfs knob introduction).
[..]
> > @@ -2182,6 +2253,7 @@ void console_unlock(void)
> > console_may_schedule = 0;
> >
> > again:
> > + clear_bit(PRINTK_PENDING_OUTPUT, &printk_pending);
>
> This will not help if new messages appear during
> call_console_drivers().
you are right. wouldn't do much harm (an extra console_unlock() from
printk_kthread in the worst case), but agree.
I added it there because of that "!can_use_console()" branch. not that
I expect printk_kthread being executed on !online CPU, but we might have
no callable consoles.
probably should have that clear_bit() before and after the loop.
-ss
