watchdog: gpio_wdt: set WDOG_HW_RUNNING in gpio_wdt_stop
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Web: https://git.kernel.org/torvalds/c/bc137dfdbec27c0ec5731a89002daded4a4aa1ea Commit: bc137dfdbec27c0ec5731a89002daded4a4aa1ea Parent: 57b6d481f7a59c091b53a18c843d8631fa04f7eb Refname: refs/heads/master Author: Rasmus Villemoes <[email protected]> AuthorDate: Thu Nov 9 14:39:55 2017 +0100 Committer: Wim Van Sebroeck <[email protected]> CommitDate: Thu Dec 28 20:45:36 2017 +0100 watchdog: gpio_wdt: set WDOG_HW_RUNNING in gpio_wdt_stop The first patch above (https://patchwork.kernel.org/patch/9970181/) makes the oops go away, but it just papers over the problem. The real problem is that the watchdog core clears WDOG_HW_RUNNING in watchdog_stop, and the gpio driver fails to set it in its stop function when it doesn't actually stop it. This means that the core doesn't know that it now has responsibility for petting the device, in turn causing the device to reset the system (I hadn't noticed this because the board I'm working on has that reset logic disabled). How about this (other drivers may of course have the same problem, I haven't checked). One might say that ->stop should return an error when the device can't be stopped, but OTOH this brings parity between a device without a ->stop method and a GPIO wd that has always-running set. IOW, I think ->stop should only return an error when an actual attempt to stop the hardware failed. From: Rasmus Villemoes <[email protected]> The watchdog framework clears WDOG_HW_RUNNING before calling ->stop. If the driver is unable to stop the device, it is supposed to set that bit again so that the watchdog core takes care of sending heart-beats while the device is not open from user-space. Update the gpio_wdt driver to honour that contract (and get rid of the redundant clearing of WDOG_HW_RUNNING). Fixes: 3c10bbde10 ("watchdog: core: Clear WDOG_HW_RUNNING before calling the stop function") Signed-off-by: Rasmus Villemoes <[email protected]> Reviewed-by: Guenter Roeck <[email protected]> Signed-off-by: Guenter Roeck <[email protected]> Signed-off-by: Wim Van Sebroeck <[email protected]> --- drivers/watchdog/gpio_wdt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c index b077c88a5ceb..3ade28190341 100644 --- a/drivers/watchdog/gpio_wdt.c +++ b/drivers/watchdog/gpio_wdt.c @@ -81,7 +81,8 @@ static int gpio_wdt_stop(struct watchdog_device *wdd) if (!priv->always_running) { gpio_wdt_disable(priv); - clear_bit(WDOG_HW_RUNNING, &wdd->status); + } else { + set_bit(WDOG_HW_RUNNING, &wdd->status); } return 0; -- To unsubscribe from this list: send the line "unsubscribe git-commits-head" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html