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Date:   Sat, 24 Sep 2022 18:31:43 +0900
From:   Sergey Senozhatsky <senozhatsky@chromium.org>
To:     John Ogness <john.ogness@linutronix.de>
Cc:     Petr Mladek <pmladek@suse.com>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH printk 06/18] printk: Protect [un]register_console() with
 a mutex
Message-ID: <Yy7OfxGA//d8QYpe@google.com>
References: <20220924000454.3319186-1-john.ogness@linutronix.de>
 <20220924000454.3319186-7-john.ogness@linutronix.de>
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On (22/09/24 02:10), John Ogness wrote:
> From: Thomas Gleixner <tglx@linutronix.de>
> 
> Unprotected list walks are a brilliant idea. Especially in the context of
> hotpluggable consoles.
> 
> The new list lock provides not only synchronization for console list
> manipulation, but also for manipulation of console->flags:
> 
>     console_list_lock();
>     console_lock();
> 
>     /* may now manipulate the console list and/or console->flags */
> 
>     console_unlock();
>     console_list_unlock();
> 
> Therefore it is safe to iterate the console list and read console->flags
> if holding either the console lock or the console list lock.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: John Ogness <john.ogness@linutronix.de>

Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>