All consoles found on for_each_console are registered, meaning that all
of them have the CON_ENABLED flag set. Since NBCON was introduced it's
important to check if a given console also implements the NBCON callbacks.
The function console_is_usable does exactly that.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
---
 arch/um/kernel/kmsg_dump.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c
index 419021175272..fc0f543d1d8e 100644
--- a/arch/um/kernel/kmsg_dump.c
+++ b/arch/um/kernel/kmsg_dump.c
@@ -31,7 +31,7 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
 		 * expected to output the crash information.
 		 */
 		if (strcmp(con->name, "ttynull") != 0 &&
-		    (console_srcu_read_flags(con) & CON_ENABLED)) {
+		    console_is_usable(con, console_srcu_read_flags(con), true)) {
 			break;
 		}
 	}

-- 
2.51.1

On Fri 2025-11-21 15:50:34, Marcos Paulo de Souza wrote:
> All consoles found on for_each_console are registered, meaning that all
> of them have the CON_ENABLED flag set. Since NBCON was introduced it's
> important to check if a given console also implements the NBCON callbacks.
> The function console_is_usable does exactly that.
> 
> Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>

Makes sense:

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr