Re: [printk] fbc14616f4: BUG:kernel_reboot-without-warning_in_test_stage

From: Pavel Machek
Date: Sun Apr 09 2017 - 05:58:23 EST


On Fri 2017-04-07 10:29:17, Steven Rostedt wrote:
> On Fri, 7 Apr 2017 10:14:49 +0200
> Pavel Machek <pavel@xxxxxx> wrote:
>
> > > serial console can be quite slow. and port->lock, that is acquired by
> > > console_unlock()->call_console_drivers()->write(), is also accessible
> > > by serial driver's IRQ handler, and this lock may be busy long
> > > enough -- as long as that IRQ handler transmits/receives chars. but
> > > that's not the point.
> >
> > Well. This is what we had for 20 years.
>
> But for the last 20 years we were not booting on machines with over 200
> CPUs. Well, we were, but those had custom kernels (which probably
> dismantled printk).

Well, not a problem. Just find a solution that works for dual core
machines as well as it did for 20 years.

2 seconds timeout as proposed earlier should work well for big
machines, and with no regressions on small machines.

Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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