[dm-devel] Serial console is causing system lock-up

[Mikulas Patocka]

On Thu, 7 Mar 2019, Sergey Senozhatsky wrote:

> On (03/06/19 11:07), Mikulas Patocka wrote:
> > This bug only happens if we select large logbuffer (millions of 
> > characters). With smaller log buffer, there are messages "** X printk 
> > messages dropped", but there's no lockup.
> > 
> > The kernel apparently puts 2 million characters into a console log buffer, 
> > then takes some lock and than tries to write all of them to a slow serial 
> > line.
> 
> Do you run a preemtible kernel?
> 
> 	-ss

The kernel has voluntary preemption.

Mikulas