linux-kernel - [PATCH 5.0 330/346] regulator: da9063: Fix notifier mutex lock warning

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Date:   Wed, 29 May 2019 20:06:43 -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 5.0 330/346] regulator: da9063: Fix notifier mutex lock warning

[ Upstream commit 29d40b4a5776ec4727c9f0e00a884423dd5e3366 ]

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: 69ca3e58d178 ("regulator: da9063: Add Dialog DA9063 voltage regulators support.")
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/da9063-regulator.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/regulator/da9063-regulator.c b/drivers/regulator/da9063-regulator.c
index 8cbcd2a3eb205..d3ea73ab59209 100644
--- a/drivers/regulator/da9063-regulator.c
+++ b/drivers/regulator/da9063-regulator.c
@@ -615,9 +615,12 @@ static irqreturn_t da9063_ldo_lim_event(int irq, void *data)
 		if (regl->info->oc_event.reg != DA9063_REG_STATUS_D)
 			continue;
 
-		if (BIT(regl->info->oc_event.lsb) & bits)
+		if (BIT(regl->info->oc_event.lsb) & bits) {
+		        regulator_lock(regl->rdev);
 			regulator_notifier_call_chain(regl->rdev,
 					REGULATOR_EVENT_OVER_CURRENT, NULL);
+		        regulator_unlock(regl->rdev);
+		}
 	}
 
 	return IRQ_HANDLED;
-- 
2.20.1