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Date:   Fri, 25 Feb 2022 14:07:00 +0900
From:   Sergey Senozhatsky <senozhatsky@chromium.org>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Petr Mladek <pmladek@suse.com>,
        John Ogness <john.ogness@linutronix.de>,
        Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: Re: Strange output on the console
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On (22/02/25 13:58), Sergey Senozhatsky wrote:
> On (22/02/24 23:00), Steven Rostedt wrote:
> > I've been noticing that my tests have been spitting out strange output on
> > the console. It would happen at boot up and then clear up. It looks like
> > something screwed up with the serial timing.
> > 
> > Attached is a dmesg of one of my test runs as an example.
> > 
> > I've noticed this on both 32 bit and 64 bit x86.
> > 
> > I haven't had time to look deeper into this, but I figured I let you know
> > about it.
> > 
> > And it always seems to happen right after:
> > 
> >   Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
> > 
> > Maybe this is a serial issue and not a printk one? :-/
> 
> Steven, did you notice this recently?
> May I perhaps suggest git bisect? (sorry)

On the off chance - do you have this revert in your kernel?

commit 6a7b9f002eca6788d346c16a6ff0c218b41f8d1d
Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date:   Wed Jan 26 14:33:58 2022 +0100

    Revert "tty: serial: Use fifo in 8250 console driver"

    This reverts commit 5021d709b31b8a14317998a33cbc78be0de9ab30.

    The patch is still a bit buggy, and this breaks some other hardware
    types.  It needs to be resubmitted in a non-buggy way, and make sure the
    other hardware types also continue to work properly.