Re: [PATCH v5 0/2] printk: Console owner and waiter logic cleanup

Sergey Senozhatsky
2018-04-23T05:35:37Z

On (01/23/18 07:43), Tejun Heo wrote:
> >
> > We can have more. But if printk is causing printks, that's a major bug.
> > And work queues are not going to fix it, it will just spread out the
> > pain. Have it be 100 printks, it needs to be fixed if it is happening.
> > And having all printks just generate more printks is not helpful. Even
> > if we slow them down. They will still never end.
>
> So, at least in the case that we were seeing, it isn't that black and
> white. printk keeps causing printks but only because printk buffer
> flushing is preventing the printk'ing context from making forward
> progress. The key problem there is that a flushing context may get
> pinned flushing indefinitely and using a separate context does solve
> the problem.

Hello Tejun,

I'm willing to take a look at those printk()-s from console drivers.
Any chance you can send me some of the backtraces you see [the most
common/disturbing]?

-ss