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>

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index ab18381..fd0e4e3 100644 (file)
--- 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);