[PATCH 4/5] watchdog: starfive-wdt: Fix runtime PM usage count leaks in probe and remove

[Guenter Roeck <linux@roeck-us.net>]

When runtime PM is enabled, starfive_wdt_probe() acquires a runtime PM
reference via pm_runtime_resume_and_get(). On subsequent probe failures,
err_exit manually disables clocks via starfive_wdt_disable_clock() and
calls pm_runtime_disable(), without dropping the acquired runtime PM
reference (and leaving the hardware timer running if early_enable was
enabled and watchdog_register_device() failed).

Similarly, when early_enable is set (or the watchdog was left running
on close), the active runtime PM reference is retained after probe, but
starfive_wdt_remove() never releases it before calling
pm_runtime_disable().

Release the runtime PM reference with pm_runtime_put_sync() on probe
error paths (stopping the watchdog first if running) and in
starfive_wdt_remove() when watchdog_hw_running() is still set.

Fixes: db728ea9c7be ("drivers: watchdog: Add StarFive Watchdog driver")
Cc: Xingyu Wu <xingyu.wu@starfivetech.com>
Cc: Ziv Xu <ziv.xu@starfivetech.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/watchdog/starfive-wdt.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/starfive-wdt.c b/drivers/watchdog/starfive-wdt.c
index 18301f5d1144..817f84cc2807 100644
--- a/drivers/watchdog/starfive-wdt.c
+++ b/drivers/watchdog/starfive-wdt.c
@@ -517,8 +517,14 @@ static int starfive_wdt_probe(struct platform_device *pdev)
 
 err_unregister_wdt:
 	watchdog_unregister_device(&wdt->wdd);
+	goto err_disable_pm;
 err_exit:
-	starfive_wdt_disable_clock(wdt);
+	if (watchdog_hw_running(&wdt->wdd))
+		starfive_wdt_stop(wdt);
+	if (pm_runtime_enabled(&pdev->dev))
+		pm_runtime_put_sync(&pdev->dev);
+	else
+		starfive_wdt_disable_clock(wdt);
 err_disable_pm:
 	pm_runtime_disable(&pdev->dev);
 
@@ -531,8 +537,11 @@ static void starfive_wdt_remove(struct platform_device *pdev)
 
 	watchdog_unregister_device(&wdt->wdd);
 
-	if (watchdog_hw_running(&wdt->wdd))
+	if (watchdog_hw_running(&wdt->wdd)) {
 		starfive_wdt_stop(wdt);
+		if (pm_runtime_enabled(&pdev->dev))
+			pm_runtime_put_sync(&pdev->dev);
+	}
 
 	if (pm_runtime_enabled(&pdev->dev))
 		pm_runtime_disable(&pdev->dev);
-- 
2.45.2