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From:   Marco Elver <elver@google.com>
Date:   Mon, 20 Jul 2020 12:32:29 +0200
Message-ID: <CANpmjNNnu2a3MqCgjieQEOFrXvs21pfxybvPkicLKO4jaBnpgA@mail.gmail.com>
Subject: Re: [PATCH v5 4/4] printk: use the lockless ringbuffer
To:     John Ogness <john.ogness@linutronix.de>
Cc:     Petr Mladek <pmladek@suse.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andrea Parri <parri.andrea@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Paul McKenney <paulmck@kernel.org>, kexec@lists.infradead.org,
        LKML <linux-kernel@vger.kernel.org>,
        Dmitry Vyukov <dvyukov@google.com>
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On Mon, 20 Jul 2020 at 12:20, John Ogness <john.ogness@linutronix.de> wrote:
>
> On 2020-07-18, Marco Elver <elver@google.com> wrote:
> > It seems this causes a regression observed at least with newline-only
> > printks.
> > [...]
> > ------ >8 ------
> >
> > --- a/init/main.c
> > +++ b/init/main.c
> > @@ -1039,6 +1039,10 @@ asmlinkage __visible void __init start_kernel(void)
> >       sfi_init_late();
> >       kcsan_init();
> >
> > +     pr_info("EXPECT BLANK LINE --vv\n");
> > +     pr_info("\n");
> > +     pr_info("EXPECT BLANK LINE --^^\n");
> > +
> >       /* Do the rest non-__init'ed, we're now alive */
> >       arch_call_rest_init();
>
> Thanks for the example. This is an unintentional regression in the
> series. I will submit a patch to fix this.
>
> Note that this regression does not exist when the followup series [0]
> (reimplementing LOG_CONT) is applied. All the more reason that the 1st
> series should be fixed before pushing the 2nd series to linux-next.

Great, thank you for clarifying! :-)

-- Marco

> John Ogness
>
> [0] https://lkml.kernel.org/r/20200717234818.8622-1-john.ogness@linutronix.de