Re: [PATCH 0/3] make printk work again

[Peter Zijlstra]

On Wed, Oct 19, 2016 at 09:04:16AM +0200, Jan Kara wrote:
> On Tue 18-10-16 19:08:30, Peter Zijlstra wrote:
> > This basically fixes printk by evading everything it does.
> > 
> > There's too many problems with printk, from sleeping locks to broken console
> > drivers. Stop using it.
> 
> I agree that printk is fragile and your patches are likely fine for machine
> where you do kernel development. However for production servers with
> hundreds of SCSI LUNs assigned I don't think it is a viable solution - I'm
> pretty sure those machines would take ages to boot (if they ever boot) with
> early_printk implementation. So do you intend this as "the ultimate printk
> solution" or just a "kernel developers debugging aid"? :)

Mostly just to scratch my itch. It also completely kills dmesg, which I
can't see being popular :-) On the plus side, these 3 little patches
seems like something mergable (as opposed to my previous approach which
basically just deleted everything printk). The first also fixes a real,
and long standing, issue with kdb_printk.

But I really do not see how printk and the console drivers as exist
today can ever yield something reliable. We've been stacking band-aids
on it for a while now, and I think we're at the point where we should
say stop this madness.

Either do a complete overhaul and redesign of the entire stack, or just
give up and admit its broken crap and leave it rot.