[PATCH] Revert "tty: serial: 8250: add CON_CONSDEV to flags"

[PATCH] Revert "tty: serial: 8250: add CON_CONSDEV to flags"

[Herbert Xu]

This commit needs to be reverted because it prevents people from
using the serial console as a secondary console with input being
directed to tty0.

IOW, if you boot with console=ttyS0 console=tty0 then all kernels
prior to this commit will produce output on both ttyS0 and tty0
but input will only be taken from tty0.  With this patch the serial
console will always be the primary console instead of tty0,
potentially preventing people from getting into their machines in
emergency situations.

Fixes: d03516df8375 ("tty: serial: 8250: add CON_CONSDEV to flags")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 240a361..e8819aa 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -675,7 +675,7 @@ static int univ8250_console_match(struct console *co, char *name, int idx,
 	.device		= uart_console_device,
 	.setup		= univ8250_console_setup,
 	.match		= univ8250_console_match,
-	.flags		= CON_PRINTBUFFER | CON_ANYTIME | CON_CONSDEV,
+	.flags		= CON_PRINTBUFFER | CON_ANYTIME,
 	.index		= -1,
 	.data		= &serial8250_reg,
 };
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH] Revert "tty: serial: 8250: add CON_CONSDEV to flags"

[Greg Kroah-Hartman]

On Sun, Dec 11, 2016 at 10:05:49AM +0800, Herbert Xu wrote:
> This commit needs to be reverted because it prevents people from
> using the serial console as a secondary console with input being
> directed to tty0.
> 
> IOW, if you boot with console=ttyS0 console=tty0 then all kernels
> prior to this commit will produce output on both ttyS0 and tty0
> but input will only be taken from tty0.  With this patch the serial
> console will always be the primary console instead of tty0,
> potentially preventing people from getting into their machines in
> emergency situations.
> 
> Fixes: d03516df8375 ("tty: serial: 8250: add CON_CONSDEV to flags")
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
> 
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> index 240a361..e8819aa 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -675,7 +675,7 @@ static int univ8250_console_match(struct console *co, char *name, int idx,
>  	.device		= uart_console_device,
>  	.setup		= univ8250_console_setup,
>  	.match		= univ8250_console_match,
> -	.flags		= CON_PRINTBUFFER | CON_ANYTIME | CON_CONSDEV,
> +	.flags		= CON_PRINTBUFFER | CON_ANYTIME,
>  	.index		= -1,
>  	.data		= &serial8250_reg,
>  };

Ok, this is the second time this has been reported.  Matthew seems to be
ignoring my email about this, so I guess I'll just revert the patch, as
it's obviously causing problems...

thanks,

greg k-h