This is a note to let you know that I've just added the patch titled
watchdog: Fix kref imbalance seen if handle_boot_enabled=0
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: watchdog-fix-kref-imbalance-seen-if-handle_boot_enabled-0.patch and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Thu Mar 22 14:26:48 CET 2018
From: Guenter Roeck linux@roeck-us.net Date: Mon, 25 Sep 2017 09:17:02 -0700 Subject: watchdog: Fix kref imbalance seen if handle_boot_enabled=0
From: Guenter Roeck linux@roeck-us.net
[ 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: 2501b015313fe ("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 --- drivers/watchdog/watchdog_dev.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)
--- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -966,14 +966,13 @@ static int watchdog_cdev_register(struct * and schedule an immediate ping. */ if (watchdog_hw_running(wdd)) { - if (handle_boot_enabled) { - __module_get(wdd->ops->owner); - kref_get(&wd_data->kref); + __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); - } + wdd->id); }
return 0;
Patches currently in stable-queue which might be from linux@roeck-us.net are
queue-4.14/watchdog-fix-potential-kref-imbalance-when-opening-watchdog.patch queue-4.14/watchdog-fix-kref-imbalance-seen-if-handle_boot_enabled-0.patch