Messages in this thread | | | Date | Thu, 12 Nov 2020 08:58:44 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [PATCH 1/2] init/console: Use ttynull as a fallback when there is no console |
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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
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