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From: Petr Mladek <pmladek@suse.com>
To: John Ogness <john.ogness@linutronix.de>
Cc: Doug Anderson <dianders@chromium.org>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org,
	Jason Wessel <jason.wessel@windriver.com>,
	Daniel Thompson <daniel.thompson@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	kgdb-bugreport@lists.sourceforge.net,
	linux-serial@vger.kernel.org
Subject: Re: [PATCH printk v2 12/38] tty: serial: kgdboc: use console_is_enabled()
Date: Mon, 7 Nov 2022 09:47:38 +0100	[thread overview]
Message-ID: <Y2jGKnSw02QLecx+@alley> (raw)
In-Reply-To: <87bkpm7kp8.fsf@jogness.linutronix.de>

On Fri 2022-11-04 17:29:15, John Ogness wrote:
> On 2022-10-24, Doug Anderson <dianders@chromium.org> wrote:
> > It actually only holds console_list_lock() even at the end of the
> > series. Still, it seems weird that we're declaring the `data_race` on
> > CON_ENABLED but not CON_BOOT ?
> 
> For my upcoming v3 I decided to drop this patch and will keep the
> existing direct reading of @flags. Instead of this patch, for v3 the
> comment will additionally mention why @flags is allowed to be directly
> read:
> 
> /*
>  * Hold the console_lock to guarantee that no consoles are
              ^^^^^^^^^^^^
>  * unregistered until the kgdboc_earlycon setup is complete.

My understanding is that this is synchronized by console_list_lock.
Or do I miss something?

>  * Trapping the exit() callback relies on exit() not being
>  * called until the trap is setup. This also allows safe
>  * traversal of the console list and race-free reading of @flags.
>  */

Best Regards,
Petr

  reply	other threads:[~2022-11-07  8:47 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-19 14:55 [PATCH printk v2 00/38] reduce console_lock scope John Ogness
2022-10-19 14:55 ` [PATCH printk v2 01/38] serial: kgdboc: Lock console list in probe function John Ogness
2022-10-19 15:41   ` Greg Kroah-Hartman
2022-10-24  5:22   ` Sergey Senozhatsky
2022-10-25  0:34   ` Doug Anderson
2022-10-19 14:55 ` [PATCH printk v2 11/38] tty: serial: earlycon: use console_is_enabled() John Ogness
2022-10-19 16:01   ` Greg Kroah-Hartman
2022-10-21 13:51   ` Petr Mladek
2022-10-19 14:55 ` [PATCH printk v2 12/38] tty: serial: kgdboc: " John Ogness
2022-10-19 16:00   ` Greg Kroah-Hartman
2022-10-21 14:10   ` Petr Mladek
2022-10-24 22:46   ` Doug Anderson
2022-10-25  0:49     ` Doug Anderson
2022-10-25 11:28       ` John Ogness
2022-11-04 16:23         ` John Ogness
2022-11-07  8:47           ` Petr Mladek [this message]
2022-11-07  9:45             ` John Ogness
2022-10-19 14:55 ` [PATCH printk v2 13/38] tty: serial: pic32_uart: " John Ogness
2022-10-19 16:01   ` Greg Kroah-Hartman
2022-10-21 14:11   ` Petr Mladek
2022-10-19 14:55 ` [PATCH printk v2 14/38] tty: serial: samsung_tty: " John Ogness
2022-10-19 16:00   ` Greg Kroah-Hartman
2022-10-21 14:14   ` Petr Mladek
2022-10-19 14:55 ` [PATCH printk v2 15/38] tty: serial: serial_core: " John Ogness
2022-10-19 16:00   ` Greg Kroah-Hartman
2022-10-21 14:14   ` Petr Mladek
2022-10-19 14:55 ` [PATCH printk v2 16/38] tty: serial: xilinx_uartps: " John Ogness
2022-10-19 16:01   ` Greg Kroah-Hartman
2022-10-21 14:23   ` Petr Mladek
2022-10-19 14:55 ` [PATCH printk v2 21/38] serial: kgdboc: use srcu console list iterator John Ogness
2022-10-19 16:02   ` Greg Kroah-Hartman
2022-10-21 15:09   ` Petr Mladek
2022-10-25  0:33     ` Doug Anderson
2022-10-19 14:55 ` [PATCH printk v2 22/38] serial: kgdboc: document console_lock usage John Ogness
2022-10-20  7:42   ` Greg Kroah-Hartman
2022-10-25  0:36   ` Doug Anderson
2022-10-25 10:09   ` Petr Mladek
2022-10-19 14:55 ` [PATCH printk v2 34/38] serial: kgdboc: use console_list_lock instead of console_lock John Ogness
2022-10-20  7:52   ` Greg Kroah-Hartman
2022-10-27 10:13   ` Petr Mladek

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