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>

1 files changed, 5 insertions, 5 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index ab1838138877..fd0e4e37f4e1 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3991,12 +3991,11 @@ 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;
 
@@ -4007,15 +4006,16 @@ 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);