linux-kernel - Applied "regulator: Fix deadlock during regulator registration" to the regulator tree

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Message-Id: <E1alKXV-0006cm-IF@finisterre>
Date:	Wed, 30 Mar 2016 11:08:21 -0700
From:	Mark Brown <broonie@...nel.org>
To:	Jon Hunter <jonathanh@...dia.com>, Mark Brown <broonie@...nel.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Applied "regulator: Fix deadlock during regulator registration" to the regulator tree

The patch

   regulator: Fix deadlock during regulator registration

has been applied to the regulator tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From a2151374230820a3a6e654f2998b2a44dbfae4e1 Mon Sep 17 00:00:00 2001
From: Jon Hunter <jonathanh@...dia.com>
Date: Wed, 30 Mar 2016 17:09:13 +0100
Subject: [PATCH] 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@...dia.com>
Signed-off-by: Mark Brown <broonie@...nel.org>
---
 drivers/regulator/core.c | 10 +++++-----
 1 file 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);

-- 
2.8.0.rc3