queue-4.14/disable-kgdboc-failed-by-echo-space-to-sys-module-kgdboc-parameters-kgdboc.patch

   1 From 3ec8002951ea173e24b466df1ea98c56b7920e63 Mon Sep 17 00:00:00 2001
   2 From: Wentao Wang <witallwang@gmail.com>
   3 Date: Wed, 20 Mar 2019 15:30:39 +0000
   4 Subject: Disable kgdboc failed by echo space to /sys/module/kgdboc/parameters/kgdboc
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 From: Wentao Wang <witallwang@gmail.com>
  10
  11 commit 3ec8002951ea173e24b466df1ea98c56b7920e63 upstream.
  12
  13 Echo "" to /sys/module/kgdboc/parameters/kgdboc will fail with "No such
  14 device” error.
  15
  16 This is caused by function "configure_kgdboc" who init err to ENODEV
  17 when the config is empty (legal input) the code go out with ENODEV
  18 returned.
  19
  20 Fixes: 2dd453168643 ("kgdboc: Fix restrict error")
  21 Signed-off-by: Wentao Wang <witallwang@gmail.com>
  22 Cc: stable <stable@vger.kernel.org>
  23 Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25
  26 ---
  27  drivers/tty/serial/kgdboc.c |    4 +++-
  28  1 file changed, 3 insertions(+), 1 deletion(-)
  29
  30 --- a/drivers/tty/serial/kgdboc.c
  31 +++ b/drivers/tty/serial/kgdboc.c
  32 @@ -148,8 +148,10 @@ static int configure_kgdboc(void)
  33         char *cptr = config;
  34         struct console *cons;
  35
  36 -       if (!strlen(config) || isspace(config[0]))
  37 +       if (!strlen(config) || isspace(config[0])) {
  38 +               err = 0;
  39                 goto noconfig;
  40 +       }
  41
  42         kgdboc_io_ops.is_console = 0;
  43         kgdb_tty_driver = NULL;