From: Guenter Roeck <linux@roeck-us.net>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Petr Mladek <pmladek@suse.com>
Cc: Shreyas Joshi <shreyas.joshi@biamp.com>,
rostedt@goodmis.org, shreyasjoshi15@gmail.com,
linux-kernel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] printk: handle blank console arguments passed in.
Date: Wed, 7 Oct 2020 08:57:06 -0700 [thread overview]
Message-ID: <be66237b-e7b2-0321-c00c-cd6fba6e3b58@roeck-us.net> (raw)
In-Reply-To: <20201007123044.GA509@jagdpanzerIV.localdomain>
On 10/7/20 5:30 AM, Sergey Senozhatsky wrote:
[ ... ]
>
> console_on_rootfs() attempts to filp_open()->tty_open() /dev/console.
> This ends up in printk's console_device(), which iterates the list of
> console drivers and returns associated console->device back to tty. The
> problem is that console drivers list is empty, so the function returns
> NULL, and filp_open("/dev/console") fails. But the console_on_rootfs()
> comment says that this function should never fail (!). This sort of
> makes me wonder if "console=" is actually legal.
>
I would not want to use a term such as "legal". It just happened to work
and was used.
> Hint: I can crash my laptop when I remove the "console=" boot param and
> comment out init_dup(file) calls in console_on_rootfs().
>
I can see to options: Link /dev/console to /dev/null if there is no console,
or do something like
if (IS_ERR(file)) {
pr_warn("Warning: unable to open an initial console.\n");
file = filp_open("/dev/null", O_RDWR, 0);
if (IS_ERR(file))
return;
}
Guenter
next prev parent reply other threads:[~2020-10-07 15:57 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 5:29 [PATCH] printk: handle blank console arguments passed in Shreyas Joshi
2020-03-17 1:34 ` Shreyas Joshi
2020-03-17 1:39 ` Steven Rostedt
2020-03-17 2:01 ` Sergey Senozhatsky
2020-03-17 2:17 ` Shreyas Joshi
2020-03-17 8:22 ` Sergey Senozhatsky
2020-05-22 6:46 ` Shreyas Joshi
2020-05-22 6:53 ` Shreyas Joshi
2020-05-22 10:00 ` Petr Mladek
2020-10-06 2:59 ` Sergey Senozhatsky
2020-10-06 3:35 ` Guenter Roeck
2020-10-06 5:08 ` Greg Kroah-Hartman
2020-10-06 11:17 ` Guenter Roeck
2020-10-06 6:59 ` Sergey Senozhatsky
2020-10-06 9:54 ` Petr Mladek
2020-10-06 13:33 ` Sergey Senozhatsky
2020-10-06 14:22 ` Guenter Roeck
2020-10-06 16:08 ` Sergey Senozhatsky
2020-10-06 9:52 ` Petr Mladek
2020-10-06 10:45 ` Guenter Roeck
2020-10-06 13:43 ` Petr Mladek
2020-10-06 16:35 ` Petr Mladek
2020-10-06 17:15 ` Sergey Senozhatsky
2020-10-07 7:28 ` Petr Mladek
2020-10-07 12:30 ` Sergey Senozhatsky
2020-10-07 14:39 ` Sergey Senozhatsky
2020-10-07 15:57 ` Guenter Roeck [this message]
2020-10-07 16:29 ` Sergey Senozhatsky
2020-10-08 5:52 ` Sergey Senozhatsky
2020-10-08 9:01 ` Petr Mladek
2020-10-08 10:56 ` Sergey Senozhatsky
2020-10-08 12:05 ` Sergey Senozhatsky
2020-10-22 11:38 ` Petr Mladek
2020-10-22 13:32 ` Sergey Senozhatsky
2020-10-08 8:50 ` Petr Mladek
2020-10-08 12:20 ` Sergey Senozhatsky
2020-10-08 12:37 ` Sergey Senozhatsky
2020-05-15 15:24 ` Petr Mladek
2020-05-20 11:50 ` Sergey Senozhatsky
2020-05-22 6:40 ` Shreyas Joshi
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