linux-kernel - [PATCH] watchdog: core: Clear WDOG_HW_RUNNING before calling the stop function

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:	Thu, 21 Jul 2016 14:21:56 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	linux-watchdog@...r.kernel.org
Cc:	Wim Van Sebroeck <wim@...ana.be>,
	Rasmus Villemoes <rasmus.villemoes@...vas.dk>,
	linux-kernel@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH] watchdog: core: Clear WDOG_HW_RUNNING before calling the stop function

WDOG_HW_RUNNING indicates that the hardware watchdog is running while the
watchdog device is closed. The flag may be set by the driver when it is
instantiated to indicate that the watchdog is running, and that the
watchdog core needs to send heartbeat requests to the driver until the
watchdog device is opened.

When the watchdog device is closed, the flag can be used by the driver's
stop function to indicate to the watchdog core that it was unable to stop
the watchdog, and that the watchdog core needs to send heartbeat requests.
This only works if the flag is actually cleared when the watchdog is
stopped. To avoid having to clear the flag in each driver's stop function,
clear it in the watchdog core before calling the stop function.

Reported-by: Rasmus Villemoes <rasmus.villemoes@...vas.dk>
Fixes: ee142889e32f ("watchdog: Introduce WDOG_HW_RUNNING flag")
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
 drivers/watchdog/watchdog_dev.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index f128efc36135..040bf8382f46 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -267,10 +267,12 @@ static int watchdog_stop(struct watchdog_device *wdd)
 		return -EBUSY;
 	}

-	if (wdd->ops->stop)
+	if (wdd->ops->stop) {
+		clear_bit(WDOG_HW_RUNNING, &wdd->status);
 		err = wdd->ops->stop(wdd);
-	else
+	} else {
 		set_bit(WDOG_HW_RUNNING, &wdd->status);
+	}

 	if (err == 0) {
 		clear_bit(WDOG_ACTIVE, &wdd->status);
-- 
2.5.0