4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Igor Pylypiv <igor.pylypiv@xxxxxxxxx> [ Upstream commit 7bd3e7b743956afbec30fb525bc3c5e22e3d475c ] Watchdog close is "expected" when any byte is 'V' not just the last one. Writing "V" to the device fails because the last byte is the end of string. $ echo V > /dev/watchdog f71808e_wdt: Unexpected close, not stopping watchdog! Signed-off-by: Igor Pylypiv <igor.pylypiv@xxxxxxxxx> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Wim Van Sebroeck <wim@xxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/watchdog/f71808e_wdt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/watchdog/f71808e_wdt.c +++ b/drivers/watchdog/f71808e_wdt.c @@ -566,7 +566,8 @@ static ssize_t watchdog_write(struct fil char c; if (get_user(c, buf + i)) return -EFAULT; - expect_close = (c == 'V'); + if (c == 'V') + expect_close = true; } /* Properly order writes across fork()ed processes */