Re: [RFC][PATCHv4 0/6] printk: use printk_safe to handle printk() recursive calls

From: Linus Torvalds
Date: Thu Oct 27 2016 - 23:30:55 EST


On Thu, Oct 27, 2016 at 8:49 AM, Sergey Senozhatsky
<sergey.senozhatsky@xxxxxxxxx> wrote:
>
> RFC
>
> This patch set extends a lock-less NMI per-cpu buffers idea to
> handle recursive printk() calls. The basic mechanism is pretty much the
> same -- at the beginning of a deadlock-prone section we switch to lock-less
> printk callback, and return back to a default printk implementation at the
> end; the messages are getting flushed to a logbuf buffer from a safer
> context.

This looks very reasonable to me.

Does this also obviate the need for "printk_deferred()" that the
scheduler and the clock code uses? Because that would be a lovely
thing to look at if it doesn't..

LInus