Messages in this thread | | | Date | Wed, 20 Jul 2022 18:35:35 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH] printk: Skip console drivers on PREEMPT_RT. |
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On 2022-07-20 18:32:43 [+0206], John Ogness wrote: > Hi Sebastian, Hi,
> > --- a/kernel/printk/printk.c > > +++ b/kernel/printk/printk.c > > @@ -2843,6 +2843,16 @@ void console_unlock(void) > > } > > > > /* > > + * On PREEMPT_RT it is not possible to invoke console drivers with > > + * disabled interrupts and or preemption. Therefore all drivers are > > + * skipped and the output can be retrieved from the buffer. > > + */ > > + if (IS_ENABLED(CONFIG_PREEMPT_RT)) { > > + up_console_sem(); > > This should be: > > __console_unlock();
Why?
> > + return; > > + } > > Note that if @console_may_schedule is 1, then we are in a sleepable > context and could print. But since that is not very often, it is > probably better to just have it off all the time as you propose.
No we can't coz printk disables interrupts before invoking the console drivers.
> John Ogness
Sebastian
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