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Commit 202b5689 authored by Viresh Kumar's avatar Viresh Kumar Committed by Lee Jones
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mfd: wm8994-core: Don't use managed regulator bulk get API 



The kernel WARNs and then crashes today if wm8994_device_init() fails
after calling devm_regulator_bulk_get().

That happens because there are multiple devices involved here and the
order in which managed resources are freed isn't correct.

The regulators are added as children of wm8994->dev.  Whereas,
devm_regulator_bulk_get() receives wm8994->dev as the device, though it
gets the same regulators which were added as children of wm8994->dev
earlier.

During failures, the children are removed first and the core eventually
calls regulator_unregister() for them. As regulator_put() was never done
for them (opposite of devm_regulator_bulk_get()), the kernel WARNs at

	WARN_ON(rdev->open_count);

And eventually it crashes from debugfs_remove_recursive().

Fix the kernel warnings and crashes by using regulator_bulk_get()
instead of devm_regulator_bulk_get() and explicitly freeing the supplies
in exit paths.

Tested on Exynos 5250, dual core ARM A15 machine.

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Acked-by: default avatarCharles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 8ca9edc8

drivers/mfd/wm8994-core.c

+11 −3
Original line number Diff line number Diff line
@@ -394,7 +394,12 @@ static int wm8994_device_init(struct wm8994 *wm8994, int irq) 
		goto err;

	}



	ret = devm_regulator_bulk_get(wm8994->dev, wm8994->num_supplies,

	/*

	 * Can't use devres helper here as some of the supplies are provided by

	 * wm8994->dev's children (regulators) and those regulators are

	 * unregistered by the devres core before the supplies are freed.

	 */

	ret = regulator_bulk_get(wm8994->dev, wm8994->num_supplies,

				 wm8994->supplies);

	if (ret != 0) {

		dev_err(wm8994->dev, "Failed to get supplies: %d\n", ret);
@@ -404,7 +409,7 @@ static int wm8994_device_init(struct wm8994 *wm8994, int irq) 
	ret = regulator_bulk_enable(wm8994->num_supplies, wm8994->supplies);

	if (ret != 0) {

		dev_err(wm8994->dev, "Failed to enable supplies: %d\n", ret);

		goto err;

		goto err_regulator_free;

	}



	ret = wm8994_reg_read(wm8994, WM8994_SOFTWARE_RESET);
@@ -595,6 +600,8 @@ static int wm8994_device_init(struct wm8994 *wm8994, int irq) 
err_enable:

	regulator_bulk_disable(wm8994->num_supplies,

			       wm8994->supplies);

err_regulator_free:

	regulator_bulk_free(wm8994->num_supplies, wm8994->supplies);

err:

	mfd_remove_devices(wm8994->dev);

	return ret;
@@ -605,6 +612,7 @@ static void wm8994_device_exit(struct wm8994 *wm8994) 
	pm_runtime_disable(wm8994->dev);

	wm8994_irq_exit(wm8994);

	regulator_bulk_disable(wm8994->num_supplies, wm8994->supplies);

	regulator_bulk_free(wm8994->num_supplies, wm8994->supplies);

	mfd_remove_devices(wm8994->dev);

}