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
next prev 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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