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From:   John Ogness <john.ogness@linutronix.de>
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To:     Daniel Thompson <daniel.thompson@linaro.org>
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,
        Jason Wessel <jason.wessel@windriver.com>,
        Douglas Anderson <dianders@chromium.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 v3 36/40] tty: serial: kgdboc: use
 console_list_lock for list traversal
In-Reply-To: <20221109090631.wbtar2ho45x5yanl@ash.lan>
References: <20221107141638.3790965-1-john.ogness@linutronix.de>
 <20221107141638.3790965-37-john.ogness@linutronix.de>
 <20221109090631.wbtar2ho45x5yanl@ash.lan>
Date:   Wed, 09 Nov 2022 10:50:43 +0106
Message-ID: <87tu388nsk.fsf@jogness.linutronix.de>
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List-ID: <linux-kernel.vger.kernel.org>
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On 2022-11-09, Daniel Thompson <daniel.thompson@linaro.org> wrote:
>> @@ -463,9 +476,14 @@ static void kgdboc_earlycon_pre_exp_handler(void)
>>  	 * serial drivers might be OK with this, print a warning once per
>>  	 * boot if we detect this case.
>>  	 */
>> -	for_each_console(con)
>> +	cookie = console_srcu_read_lock();
>> +	for_each_console_srcu(con) {
>>  		if (con == kgdboc_earlycon_io_ops.cons)
>> -			return;
>> +			break;
>> +	}
>> +	console_srcu_read_unlock(cookie);
>> +	if (con)
>> +		return;
>
> This change isn't mentioned in the patch description.

I will move this change into its own separate patch.

    tty: serial: kgdboc: use srcu console list iterator

    Use srcu console list iteration for safe console list traversal.

Thanks.

John