Re: sched: serial port lockdep warning when offlining CPUs

[Peter Zijlstra]

(please linewrap normal text at 72 chars)

On Thu, Sep 28, 2017 at 11:45:30AM +0000, Levin, Alexander (Sasha Levin) wrote:
> Okay, that seems to have delt with the callbacks supressed issue.
> 
> I also seem to be hitting it as a result of the scheduler triggering a
> WARN, where print_stack_trace(), for example, just uses printk().
> 
> Now I'm not sure what's your approach here, do we keep converting
> printk to printk_deferred one by one until we whacked every mole?

Nah.. WARN's _should_ not trigger. If they do we fix that.

Getting a lockdep splat after a WARN is something I can live with.

And you really don't want that deferred nonsense for WARNs, because that
means you'll risk not over getting the output.