linux-kernel - [PATCH 5.0 334/346] regulator: da9062: Fix notifier mutex lock warning

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Message-Id: <20190530030557.666152416@linuxfoundation.org>
Date:   Wed, 29 May 2019 20:06:47 -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 5.0 334/346] regulator: da9062: Fix notifier mutex lock warning

[ Upstream commit 978995def0f6030aa6b3b494682f673aca13881b ]

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: 4068e5182ada ("regulator: da9062: DA9062 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/da9062-regulator.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/regulator/da9062-regulator.c b/drivers/regulator/da9062-regulator.c
index 34a70d9dc450e..5224304c10b3f 100644
--- a/drivers/regulator/da9062-regulator.c
+++ b/drivers/regulator/da9062-regulator.c
@@ -974,8 +974,10 @@ static irqreturn_t da9062_ldo_lim_event(int irq, void *data)
 			continue;
 
 		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);
 			handled = IRQ_HANDLED;
 		}
 	}
-- 
2.20.1