linux-kernel - [PATCH RESEND 3/4] regulator: avoid resolve

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Message-Id: <c6171057cfc0896f950c4d8cb82df0f9f1b89ad9.1605226675.git.mirq-linux@rere.qmqm.pl>
Date:   Fri, 13 Nov 2020 01:20:28 +0100
From:   Michał Mirosław <mirq-linux@...e.qmqm.pl>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     Ahmad Fatoum <a.fatoum@...gutronix.de>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: [PATCH RESEND 3/4] regulator: avoid resolve_supply() infinite
 recursion

When a regulator's name equals its supply's name the
regulator_resolve_supply() recurses indefinitely. Add a check
so that debugging the problem is easier. The "fixed" commit
just exposed the problem.

Fixes: aea6cb99703e ("regulator: resolve supply after creating regulator")
Cc: stable@...r.kernel.org
Reported-by: Ahmad Fatoum <a.fatoum@...gutronix.de>
Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
---
 drivers/regulator/core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index ad36f03d7ee6..ab922ed273f3 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1841,6 +1841,12 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
 		}
 	}
 
+	if (r == rdev) {
+		dev_err(dev, "Supply for %s (%s) resolved to itself\n",
+			rdev->desc->name, rdev->supply_name);
+		return -EINVAL;
+	}
+
 	/*
 	 * If the supply's parent device is not the same as the
 	 * regulator's parent device, then ensure the parent device
-- 
2.20.1