[PATCH v1 1/2] um: fix default console kernel parameter

[PATCH v1 1/2] um: fix default console kernel parameter

[Christian Lamparter]

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: d7ffac33631b ("um: stdio_console: Make preferred console")
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
---
 arch/um/kernel/um_arch.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 9838967d0b2f..9c6991f42131 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -32,7 +32,7 @@
 #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 };
-- 
2.36.1


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[PATCH v1 2/2] um: increase default virtual physical memory to 64 MiB

[Christian Lamparter]

The current 32 MiB of RAM causes OOMs to appear shortly after
booting in a minimal OpenWrt 22.03 configuration with a
5.10.134 kernel.

Of course, passing a "mem=64M" (from the --help text) parameter
works too, but it produces the following (info) message:

| [    0.000000] Unknown kernel command line parameters "mem=64M", will be passed to user space.

That's why, I think it would be nicer, if this is working out
of the box again :).

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
---
 arch/um/kernel/um_arch.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 9c6991f42131..58aee676989c 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -131,7 +131,7 @@ static int have_root __initdata;
 static int have_console __initdata;
 
 /* Set in uml_mem_setup and modified in linux_main */
-long long physmem_size = 32 * 1024 * 1024;
+long long physmem_size = 64 * 1024 * 1024;
 EXPORT_SYMBOL(physmem_size);
 
 static const char *usage_string =
-- 
2.36.1


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