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From:   John Ogness <john.ogness@linutronix.de>
To:     Martin =?utf-8?Q?Hundeb=C3=B8ll?= <martin@geanix.com>,
        Petr Mladek <pmladek@suse.com>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        linux-kernel@vger.kernel.org,
        Martin =?utf-8?Q?Hundeb=C3=B8ll?= <martin@geanix.com>
Subject: Re: [PATCH 2/2] reboot: flush printk buffers before final shutdown
In-Reply-To: <20231030092432.3434623-2-martin@geanix.com>
References: <20231030092432.3434623-1-martin@geanix.com>
 <20231030092432.3434623-2-martin@geanix.com>
Date:   Tue, 31 Oct 2023 12:18:05 +0106
Message-ID: <87edhbf3lm.fsf@jogness.linutronix.de>
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On 2023-10-30, Martin Hundeb=C3=B8ll <martin@geanix.com> wrote:
> Make sure printed messages are in fact printed before putting the system
> down.
>
> Signed-off-by: Martin Hundeb=C3=B8ll <martin@geanix.com>
> ---
>  kernel/reboot.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/kernel/reboot.c b/kernel/reboot.c
> index 3bba88c7ffc6..bab8350d5dae 100644
> --- a/kernel/reboot.c
> +++ b/kernel/reboot.c
> @@ -273,6 +273,7 @@ void kernel_restart(char *cmd)
>  	else
>  		pr_emerg("Restarting system with command '%s'\n", cmd);
>  	kmsg_dump(KMSG_DUMP_SHUTDOWN);
> +	pr_flush(1000, false);

printk() tries to print directly from the calling context. Are you
experiencing problems where you do not see the restarting message?

John Ogness