linux-kernel - [PATCH 5.0 335/346] regulator: da9055: Fix notifier mutex lock warning

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Date:   Wed, 29 May 2019 20:06:48 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Adam Thomson <Adam.Thomson.Opensource@...semi.com>,
        Steve Twiss <stwiss.opensource@...semi.com>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.0 335/346] regulator: da9055: Fix notifier mutex lock warning

[ Upstream commit 5e6afb3832bedf420dd8e4c5b32ed85117c5087d ]

The mutex for the regulator_dev must be controlled by the caller of
the regulator_notifier_call_chain(), as described in the comment
for that function.

Failure to mutex lock and unlock surrounding the notifier call results
in a kernel WARN_ON_ONCE() which will dump a backtrace for the
regulator_notifier_call_chain() when that function call is first made.
The mutex can be controlled using the regulator_lock/unlock() API.

Fixes: f6130be652d0 ("regulator: DA9055 regulator driver")
Suggested-by: Adam Thomson <Adam.Thomson.Opensource@...semi.com>
Signed-off-by: Steve Twiss <stwiss.opensource@...semi.com>
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/regulator/da9055-regulator.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/regulator/da9055-regulator.c b/drivers/regulator/da9055-regulator.c
index 588c3d2445cf3..acba42d5b57d4 100644
--- a/drivers/regulator/da9055-regulator.c
+++ b/drivers/regulator/da9055-regulator.c
@@ -515,8 +515,10 @@ static irqreturn_t da9055_ldo5_6_oc_irq(int irq, void *data)
 {
 	struct da9055_regulator *regulator = data;
 
+	regulator_lock(regulator->rdev);
 	regulator_notifier_call_chain(regulator->rdev,
 				      REGULATOR_EVENT_OVER_CURRENT, NULL);
+	regulator_unlock(regulator->rdev);
 
 	return IRQ_HANDLED;
 }
-- 
2.20.1