Re: Regression in next with use printk_safe buffers in printk

From: Sergey Senozhatsky
Date: Wed Feb 15 2017 - 23:25:01 EST


On (02/15/17 20:03), Tony Lindgren wrote:
> * Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx> [170215 17:32]:
> > On (02/15/17 10:01), Tony Lindgren wrote:
> > [..]
> > > Below is another issue I noticed caused by commit f975237b7682 that
> > > I noticed during booting.
> >
> > do you mean that with f975237b7682 you _always_ see that illegal RCU
> > usage warning?
>
> Yeah on every boot on devices using cpuidle_coupled.

does this mean that with the printk-safe patches reverted
(so, basically, the same conditions module 4 printk patches)
you don't see illegal RCU usage reports? at the moment I can't
see any connection between f975237b7682 and RCU usage from idle CPU.

[..]

> > ---
> >
> > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> > index 7180088cbb23..34da86e73d00 100644
> > --- a/kernel/printk/printk.c
> > +++ b/kernel/printk/printk.c
> > @@ -1563,7 +1563,7 @@ static void call_console_drivers(const char *ext_text, size_t ext_len,
> > {
> > struct console *con;
> >
> > - trace_console(text, len);
> > + trace_console_rcuidle(text, len);
> >
> > if (!console_drivers)
> > return;
> >
> > ---
> >
> >
> > I need to look more at this.
>
> That fixes it for me thanks, so feel free to add:
>
> Tested-by: Tony Lindgren <tony@xxxxxxxxxxx>

thanks.

-ss