4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Wentao Wang <witallwang@xxxxxxxxx>
commit 3ec8002951ea173e24b466df1ea98c56b7920e63 upstream.
Echo "" to /sys/module/kgdboc/parameters/kgdboc will fail with "No such
device” error.
This is caused by function "configure_kgdboc" who init err to ENODEV
when the config is empty (legal input) the code go out with ENODEV
returned.
Fixes: 2dd453168643 ("kgdboc: Fix restrict error")
Signed-off-by: Wentao Wang <witallwang@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Acked-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/kgdboc.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c
@@ -148,8 +148,10 @@ static int configure_kgdboc(void)
char *cptr = config;
struct console *cons;
- if (!strlen(config) || isspace(config[0]))
+ if (!strlen(config) || isspace(config[0])) {
+ err = 0;
goto noconfig;
+ }
kgdboc_io_ops.is_console = 0;
kgdb_tty_driver = NULL;
