linux/init
Petr Mladek 757055ae8d init/console: Use ttynull as a fallback when there is no console
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 48021f9813 ("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.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20201111135450.11214-2-pmladek@suse.com
2020-11-20 12:23:50 +01:00
..
calibrate.c
do_mounts_initrd.c Merge branch 'hch.init_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 09:40:34 -07:00
do_mounts_rd.c init: add an init_unlink helper 2020-07-31 08:17:52 +02:00
do_mounts.c init: add an init_chroot helper 2020-07-31 08:17:52 +02:00
do_mounts.h init: add an init_mknod helper 2020-07-31 08:17:54 +02:00
init_task.c io_uring: don't rely on weak ->files references 2020-09-30 20:32:32 -06:00
initramfs.c init: fix error check in clean_path() 2020-09-04 09:16:58 -07:00
Kconfig networking changes for the 5.10 merge window 2020-10-15 18:42:13 -07:00
main.c init/console: Use ttynull as a fallback when there is no console 2020-11-20 12:23:50 +01:00
Makefile md: move the early init autodetect code to drivers/md/ 2020-07-16 15:34:47 +02:00
noinitramfs.c init: add an init_mknod helper 2020-07-31 08:17:54 +02:00
version.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00