From: Jon Hunter <jonathanh@nvidia.com>
Date: Wed, 30 Mar 2016 16:09:13 +0000 (+0100)
Subject: UPSTREAM: regulator: Fix deadlock during regulator registration
X-Git-Tag: firefly_0821_release~469
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5dc7257e197d8d7c6e0289231f630a45ffc6fde2;p=firefly-linux-kernel-4.4.55.git

UPSTREAM: regulator: Fix deadlock during regulator registration

Commit 5e3ca2b349b1 ("regulator: Try to resolve regulators supplies on
registration") added a call to regulator_resolve_supply() within
regulator_register() where the regulator_list_mutex is held. This causes
a deadlock to occur on the Tegra114 Dalmore board when the palmas PMIC
is registered because regulator_register_resolve_supply() calls
regulator_dev_lookup() which may try to acquire the regulator_list_mutex
again.

Fix this by releasing the mutex before calling
regulator_register_resolve_supply() and update the error exit path to
ensure the mutex is released on an error.

[Made commit message more legible -- broonie]

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
(cherry picked from commit a2151374230820a3a6e654f2998b2a44dbfae4e1)

Change-Id: I65ac4aeac254d2ef3f161c422b92defd5badbbc4
Signed-off-by: David Wu <david.wu@rock-chips.com>
---

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 0d57cd6c3f24..34ae2745d3f3 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3998,12 +3998,11 @@ regulator_register(const struct regulator_desc *regulator_desc,
 	}
 
 	rdev_init_debugfs(rdev);
+	mutex_unlock(&regulator_list_mutex);
 
 	/* try to resolve regulators supply since a new one was registered */
 	class_for_each_device(&regulator_class, NULL, NULL,
 			      regulator_register_resolve_supply);
-out:
-	mutex_unlock(&regulator_list_mutex);
 	kfree(config);
 	return rdev;
 
@@ -4014,15 +4013,16 @@ scrub:
 	regulator_ena_gpio_free(rdev);
 	device_unregister(&rdev->dev);
 	/* device core frees rdev */
-	rdev = ERR_PTR(ret);
 	goto out;
 
 wash:
 	regulator_ena_gpio_free(rdev);
 clean:
 	kfree(rdev);
-	rdev = ERR_PTR(ret);
-	goto out;
+out:
+	mutex_unlock(&regulator_list_mutex);
+	kfree(config);
+	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(regulator_register);