[PATCH v7 3/7] printk: Flag register_console() if console is set on command line

Tony Lindgren
2024-03-27T11:03:23Z

If add_preferred_console() is not called early in setup_console(), we can
end up having register_console() call try_enable_default_console() before a
console device has called add_preferred_console().

Let's set console_set_on_cmdline flag in console_setup() to prevent this
from happening.

Signed-off-by: Tony Lindgren <tony@atomide.com>
---
kernel/printk/printk.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2498,6 +2498,9 @@ static int __init console_setup(char *str)
if (console_opt_save(str, brl_options))
return 1;

+ /* Flag register_console() to not call try_enable_default_console() */
+ console_set_on_cmdline = 1;
+
/* Don't attempt to parse a DEVNAME:0.0 style console */
if (strchr(str, ':'))
return 1;
@@ -3501,7 +3504,7 @@ void register_console(struct console *newcon)
* Note that a console with tty binding will have CON_CONSDEV
* flag set and will be first in the list.
*/
- if (preferred_console < 0) {
+ if (preferred_console < 0 && !console_set_on_cmdline) {
if (hlist_empty(&console_list) || !console_first()->device ||
console_first()->flags & CON_BOOT) {
try_enable_default_console(newcon);
--
2.44.0