Commit aecd123f authored Feb 28, 2018 by Igor Pylypiv Committed by Greg Kroah-Hartman May 30, 2018

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>

parent 57a85742

drivers/watchdog/f71808e_wdt.c

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -566,7 +566,8 @@ static ssize_t watchdog_write(struct file file, const char __user buf,
	char c;		char c;
	if (get_user(c, buf + i))		if (get_user(c, buf + i))
	return -EFAULT;		return -EFAULT;
	expect_close = (c == 'V');		if (c == 'V')
			expect_close = true;
	}		}

	/* Properly order writes across fork()ed processes */		/* Properly order writes across fork()ed processes */