linux-kernel - [PATCH 02/13] regulator: da9062: Fix notifier mutex lock warning

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Message-ID: <0181de94266385cfffe1c2cd0c199f1c49ca6b7b.1551808797.git.stwiss.opensource@diasemi.com>
Date:   Tue, 26 Feb 2019 15:19:34 +0000
From:   Steve Twiss <stwiss.opensource@...semi.com>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
CC:     Support Opensource <support.opensource@...semi.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 02/13] regulator: da9062: Fix notifier mutex lock warning

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>
---
 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 34a70d9..5224304 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;
 		}
 	}
-- 
1.9.3