Commit 71233e25 authored Sep 25, 2017 by Guenter Roeck Committed by Greg Kroah-Hartman Mar 24, 2018

watchdog: Fix kref imbalance seen if handle_boot_enabled=0




[ Upstream commit 914d65f3f013ba2556c7beec5d3baac7b3292504 ]

If handle_boot_enabled is set to 0, the watchdog driver module use
counter will not be increased and kref_get() will not be called when
registering the watchdog. Subsequently, on open, this does not happen
either because the code believes that it was already done because the
hardware watchdog is marked as running.

We could introduce a state variable to indicate this state, but let's
just increase the module use counter and call kref_get() unconditionally
if the hardware watchdog is running when a driver is registering itself
to keep the code simple.

Fixes: 2501b015 ("watchdog: core: add option to avoid early ...")
Cc: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
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 08b81090

drivers/watchdog/watchdog_dev.c

+5 −6

Original line number	Diff line number	Diff line
		@@ -966,15 +966,14 @@ static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno)
		* and schedule an immediate ping.
		*/
		if (watchdog_hw_running(wdd)) {
		if (handle_boot_enabled) {
		__module_get(wdd->ops->owner);
		kref_get(&wd_data->kref);
		if (handle_boot_enabled)
		queue_delayed_work(watchdog_wq, &wd_data->work, 0);
		} else {
		else
		pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n",
		wdd->id);
		}
		}

		return 0;
		}