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From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	David Gow <davidgow@google.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Shuah Khan <skhan@linuxfoundation.org>,
	Brendan Higgins <brendanhiggins@google.com>,
	KUnit Development <kunit-dev@googlegroups.com>,
	"open list:KERNEL SELFTEST FRAMEWORK" 
	<linux-kselftest@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Guenter Roeck <linux@roeck-us.net>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	linux-um <linux-um@lists.infradead.org>
Subject: Re: kunit stopped working
Date: Thu, 7 Jan 2021 16:15:04 +0900	[thread overview]
Message-ID: <X/a0+Cb6xFZOEk7x@jagdpanzerIV.localdomain> (raw)
In-Reply-To: <X/W2sl7RMvfaV4Ru@alley>

On (21/01/06 14:10), Petr Mladek wrote:
> > > 
> > > But I am not completely sure that it is the right solution.
> > 
> > Wow, hmm, puzzled. Why does it help?
> 
> I have been as well. But it seems that I got it, see below.

Thanks!

[..]
> 
> Alternative solution is to ignore ttynull as the fallback console
> in register_console(). I mean the following:

I personally would prefer a very explicit fix (IOW, the patch below),
rather than relying on some initcall trickery (which has already
failed on us)

> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index ffdd0dc7ec6d..cdb77903b0af 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -2816,8 +2816,12 @@ void register_console(struct console *newcon)
>  	 *	See if we want to use this console driver. If we
>  	 *	didn't select a console we take the first one
>  	 *	that registers here.
> +	 *
> +	 *	Ignore ttynull console. It should be used only
> +	 *	when explicitly configured or as an ultimate
> +	 *	fallback when no better console gets registered at all.
>  	 */
> -	if (!has_preferred_console) {
> +	if (!has_preferred_console && strcmp(newcon->name, "ttynull") != 0) {
>  		if (newcon->index < 0)
>  			newcon->index = 0;
>  		if (newcon->setup == NULL ||

So IIUC in case of ttynull fallback (console= ) we still end up setting
CON_CONSDEV on nulltty console, but we do it in try_enable_new_console().

Feel free to add
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

	-ss

WARNING: multiple messages have this Message-ID (diff)
From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	"open list:KERNEL SELFTEST FRAMEWORK"
	<linux-kselftest@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Brendan Higgins <brendanhiggins@google.com>,
	linux-um <linux-um@lists.infradead.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	David Gow <davidgow@google.com>,
	Shuah Khan <skhan@linuxfoundation.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Guenter Roeck <linux@roeck-us.net>,
	KUnit Development <kunit-dev@googlegroups.com>
Subject: Re: kunit stopped working
Date: Thu, 7 Jan 2021 16:15:04 +0900	[thread overview]
Message-ID: <X/a0+Cb6xFZOEk7x@jagdpanzerIV.localdomain> (raw)
In-Reply-To: <X/W2sl7RMvfaV4Ru@alley>

On (21/01/06 14:10), Petr Mladek wrote:
> > > 
> > > But I am not completely sure that it is the right solution.
> > 
> > Wow, hmm, puzzled. Why does it help?
> 
> I have been as well. But it seems that I got it, see below.

Thanks!

[..]
> 
> Alternative solution is to ignore ttynull as the fallback console
> in register_console(). I mean the following:

I personally would prefer a very explicit fix (IOW, the patch below),
rather than relying on some initcall trickery (which has already
failed on us)

> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index ffdd0dc7ec6d..cdb77903b0af 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -2816,8 +2816,12 @@ void register_console(struct console *newcon)
>  	 *	See if we want to use this console driver. If we
>  	 *	didn't select a console we take the first one
>  	 *	that registers here.
> +	 *
> +	 *	Ignore ttynull console. It should be used only
> +	 *	when explicitly configured or as an ultimate
> +	 *	fallback when no better console gets registered at all.
>  	 */
> -	if (!has_preferred_console) {
> +	if (!has_preferred_console && strcmp(newcon->name, "ttynull") != 0) {
>  		if (newcon->index < 0)
>  			newcon->index = 0;
>  		if (newcon->setup == NULL ||

So IIUC in case of ttynull fallback (console= ) we still end up setting
CON_CONSDEV on nulltty console, but we do it in try_enable_new_console().

Feel free to add
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

	-ss

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  reply	other threads:[~2021-01-07  7:16 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-21 14:43 kunit stopped working Andy Shevchenko
2020-12-21 14:45 ` Andy Shevchenko
2020-12-21 18:37   ` Shuah Khan
2020-12-21 19:27     ` Andy Shevchenko
2020-12-21 19:40       ` Andy Shevchenko
2020-12-21 20:03         ` Andy Shevchenko
2020-12-22  1:43           ` David Gow
2020-12-22  1:43             ` David Gow
2020-12-22  7:26             ` David Gow
2020-12-22  7:26               ` David Gow
2020-12-22 13:34               ` Andy Shevchenko
2020-12-22 13:34                 ` Andy Shevchenko
2020-12-27 19:58                 ` Brendan Higgins
2020-12-27 19:58                   ` Brendan Higgins
2021-01-05 16:17             ` Petr Mladek
2021-01-05 16:17               ` Petr Mladek
2021-01-05 16:49               ` Petr Mladek
2021-01-05 16:49                 ` Petr Mladek
2021-01-06  4:04                 ` Sergey Senozhatsky
2021-01-06  4:04                   ` Sergey Senozhatsky
2021-01-06 13:10                   ` Petr Mladek
2021-01-06 13:10                     ` Petr Mladek
2021-01-07  7:15                     ` Sergey Senozhatsky [this message]
2021-01-07  7:15                       ` Sergey Senozhatsky

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