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um: fix default console kernel parameter
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OpenWrt's UML with 5.15 was producing odd errors/warnings during preinit
part of the early userspace portion:

|[    0.000000] Kernel command line: ubd0=root.img root=98:0 console=tty
|[...]
|[    0.440000] random: jshn: uninitialized urandom read (4 bytes read)
|[    0.460000] random: jshn: uninitialized urandom read (4 bytes read)
|/etc/preinit: line 47: can't create /dev/tty: No such device or address
|/etc/preinit: line 48: can't create /dev/tty: No such device or address
|/etc/preinit: line 58: can't open /dev/tty: No such device or address
|[...] repeated many times

That "/dev/tty" came from the command line (which is automatically
added if no console= parameter was specified for the uml binary).

The TLDP project tells the following about the /dev/tty:
<https://tldp.org/HOWTO/Text-Terminal-HOWTO-7.html#ss7.3>
| /dev/tty stands for the controlling terminal (if any) for the current
| process.[...]
| /dev/tty is something like a link to the actually terminal device[..]

The "(if any)" is important here, since it's possible for processes to
not have a controlling terminal.

I think this was a simple typo and the author wanted tty0 there.

CC: Thomas Meyer <thomas@m3y3r.de>
Fixes: d7ffac3 ("um: stdio_console: Make preferred console")
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Christian Lamparter authored and Richard Weinberger committed Sep 19, 2022
1 parent d27fff3 commit 782b1f7
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion arch/um/kernel/um_arch.c
Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@
#include "um_arch.h"

#define DEFAULT_COMMAND_LINE_ROOT "root=98:0"
#define DEFAULT_COMMAND_LINE_CONSOLE "console=tty"
#define DEFAULT_COMMAND_LINE_CONSOLE "console=tty0"

/* Changed in add_arg and setup_arch, which run before SMP is started */
static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
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