Re: [BUG] Threaded printk breaks early debugging

From: Sergey Senozhatsky
Date: Sat Jun 11 2022 - 23:13:58 EST


On (22/06/10 11:34), Peter Geis wrote:
> > On 2022-06-10, Peter Geis <pgwipeout@xxxxxxxxx> wrote:
> > > However I've run into an issue debugging early boot issues. Anything
> > > that causes the kernel threading system to die (for example here, a
> > > NPE) causes the boot console to halt before it outputs the error.
> >
> > A null pointer exception should trigger a panic, which will cause printk
> > to enter direct mode for the oops. It should be just as effective as
> > before introducing the printing kthreads.
>
> This might be a side effect of the fact that this is on a low powered
> arm64 board. I noticed with threading enabled during large bursts the
> console drops an excessive amount of messages. It's especially
> apparent during the handover from earlycon to the normal console.

How many CPUs does it have?