[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <87r0y4m955.fsf@jogness.linutronix.de>
Date: Tue, 15 Nov 2022 18:21:34 +0106
From: John Ogness <john.ogness@...utronix.de>
To: Petr Mladek <pmladek@...e.com>
Cc: Sergey Senozhatsky <senozhatsky@...omium.org>,
Steven Rostedt <rostedt@...dmis.org>,
Thomas Gleixner <tglx@...utronix.de>,
linux-kernel@...r.kernel.org
Subject: Re: replay log: Re: [PATCH printk v4 38/39] printk: relieve
console_lock of list synchronization duties
On 2022-11-15, Petr Mladek <pmladek@...e.com> wrote:
>>> --- a/kernel/printk/printk.c
>>> +++ b/kernel/printk/printk.c
>>> @@ -3334,6 +3330,11 @@ void register_console(struct console *newcon)
>>> * boot console that is the furthest behind.
>>> */
>>> if (bootcon_registered && !keep_bootcon) {
>>> + /*
>>> + * Hold the console_lock to guarantee safe access to
>>> + * console->seq.
>>> + */
>>> + console_lock();
>>> for_each_console(con) {
>>> if ((con->flags & CON_BOOT) &&
>>> (con->flags & CON_ENABLED) &&
>>> @@ -3341,6 +3342,7 @@ void register_console(struct console *newcon)
>>> newcon->seq = con->seq;
>>> }
>>> }
>>> + console_unlock();
>
> So, without the above two hunks:
>
> Reviewed-by: Petr Mladek <pmladek@...e.com>
Note that we actually need those hunks to guarantee a consistent @seq
value. The console_lock is the only synchronization mechanism available
to read console->seq.
John
Powered by blists - more mailing lists