This is a note to let you know that I've just added the patch titled Disable kgdboc failed by echo space to to my tty git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git in the tty-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From 3ec8002951ea173e24b466df1ea98c56b7920e63 Mon Sep 17 00:00:00 2001 From: Wentao Wang <witallwang@xxxxxxxxx> Date: Wed, 20 Mar 2019 15:30:39 +0000 Subject: Disable kgdboc failed by echo space to /sys/module/kgdboc/parameters/kgdboc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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(-) diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c index 6fb312e7af71..bfe5e9e034ec 100644 --- 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; -- 2.21.0