From 63efa8423d9c73461aabc532ef98f07a575e5b1c Mon Sep 17 00:00:00 2001 From: Igor Pylypiv <igor.pylypiv@gmail.com> Date: Wed, 28 Feb 2018 00:59:12 -0800 Subject: [PATCH] watchdog: f71808e_wdt: Fix magic close handling [ 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@gmail.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/watchdog/f71808e_wdt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c index aa93df5833dc..2048aad91add 100644 --- a/drivers/watchdog/f71808e_wdt.c +++ b/drivers/watchdog/f71808e_wdt.c @@ -520,7 +520,8 @@ static ssize_t watchdog_write(struct file *file, const char __user *buf, 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 */