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From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	John Ogness <john.ogness@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Guenter Roeck <linux@roeck-us.net>,
	Shreyas Joshi <shreyas.joshi@biamp.com>,
	shreyasjoshi15@gmail.com,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] init/console: Use ttynull as a fallback when there is no console
Date: Thu, 12 Nov 2020 08:58:44 +0900	[thread overview]
Message-ID: <X6x6tMSnS60EGNef@jagdpanzerIV.localdomain> (raw)
In-Reply-To: <20201111135450.11214-2-pmladek@suse.com>

On (20/11/11 14:54), Petr Mladek wrote:
> stdin, stdout, and stderr standard I/O stream are created for the init
> process. They are not available when there is no console registered
> for /dev/console. It might lead to a crash when the init process
> tries to use them, see the commit 48021f98130880dd742 ("printk: handle
> blank console arguments passed in.").
> 
> Normally, ttySX and ttyX consoles are used as a fallback when no consoles
> are defined via the command line, device tree, or SPCR. But there
> will be no console registered when an invalid console name is configured
> or when the configured consoles do not exist on the system.
> 
> Users even try to avoid the console intentionally, for example,
> by using console="" or console=null. It is used on production
> systems where the serial port or terminal are not visible to
> users. Pushing messages to these consoles would just unnecessary
> slowdown the system.
> 
> Make sure that stdin, stdout, stderr, and /dev/console are always
> available by a fallback to the existing ttynull driver. It has
> been implemented for exactly this purpose but it was used only
> when explicitly configured.
> 
> Signed-off-by: Petr Mladek <pmladek@suse.com>

Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

	-ss

  parent reply	other threads:[~2020-11-12  1:36 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-11 13:54 [PATCH 0/2] printk/console: Use ttynull when no console is available or wanted Petr Mladek
2020-11-11 13:54 ` [PATCH 1/2] init/console: Use ttynull as a fallback when there is no console Petr Mladek
2020-11-11 16:36   ` Greg Kroah-Hartman
2020-11-11 22:52   ` Guenter Roeck
2020-11-11 23:58   ` Sergey Senozhatsky [this message]
2020-11-12  0:17   ` Sergey Senozhatsky
2020-11-12  1:45     ` Sergey Senozhatsky
2020-11-16 16:20       ` Petr Mladek
2021-01-06 23:36   ` ARC no console output (was Re: [PATCH 1/2] init/console: Use ttynull as a fallback when there is no console) Vineet Gupta
2021-01-07  9:02     ` John Ogness
2021-01-07 13:14       ` Greg Ungerer
2021-01-07 16:43       ` Vineet Gupta
2021-01-07 17:04         ` Petr Mladek
2021-01-07 17:58           ` Vineet Gupta
2021-01-08  3:48             ` Sergey Senozhatsky
2021-01-08  5:18               ` Vineet Gupta
2021-01-08  9:30                 ` Petr Mladek
2021-01-13 22:07             ` Peter Korsgaard
2021-01-07  9:09     ` Richard Weinberger
2021-01-07 12:48     ` Petr Mladek
2021-01-07 15:27     ` [Buildroot] " Yann E. MORIN
2020-11-11 13:54 ` [PATCH 2/2] printk/console: Allow to disable console output by using console="" or console=null Petr Mladek
2020-11-11 22:52   ` Guenter Roeck
2020-11-11 23:59   ` Sergey Senozhatsky
2020-11-20 14:24 ` [PATCH 0/2] printk/console: Use ttynull when no console is available or wanted Petr Mladek

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