linux-kernel - Re: [PATCH 2/2] reboot: flush printk buffers before final shutdown

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <87edhbf3lm.fsf@jogness.linutronix.de>
Date:   Tue, 31 Oct 2023 12:18:05 +0106
From:   John Ogness <john.ogness@...utronix.de>
To:     Martin Hundebøll <martin@...nix.com>,
        Petr Mladek <pmladek@...e.com>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        Sergey Senozhatsky <senozhatsky@...omium.org>,
        linux-kernel@...r.kernel.org,
        Martin Hundebøll <martin@...nix.com>
Subject: Re: [PATCH 2/2] reboot: flush printk buffers before final shutdown

On 2023-10-30, Martin Hundebøll <martin@...nix.com> wrote:
> Make sure printed messages are in fact printed before putting the system
> down.
>
> Signed-off-by: Martin Hundebøll <martin@...nix.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