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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Johan Hovold" <johan@kernel.org>,
        "Dmitry Torokhov" <dmitry.torokhov@gmail.com>
Date:   Wed, 28 Feb 2018 15:20:18 +0000
Message-ID: <lsq.1519831218.186829863@decadent.org.uk>
Subject: [PATCH 3.16 189/254] Input: 88pm860x-ts - fix child-node lookup
In-Reply-To: <lsq.1519831217.271785318@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.55-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@kernel.org>

commit 906bf7daa0618d0ef39f4872ca42218c29a3631f upstream.

Fix child node-lookup during probe, which ended up searching the whole
device tree depth-first starting at parent rather than just matching on
its children.

To make things worse, the parent node was prematurely freed, while the
child node was leaked.

Fixes: 2e57d56747e6 ("mfd: 88pm860x: Device tree support")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/input/touchscreen/88pm860x-ts.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

--- a/drivers/input/touchscreen/88pm860x-ts.c
+++ b/drivers/input/touchscreen/88pm860x-ts.c
@@ -126,7 +126,7 @@ static int pm860x_touch_dt_init(struct p
 	int data, n, ret;
 	if (!np)
 		return -ENODEV;
-	np = of_find_node_by_name(np, "touch");
+	np = of_get_child_by_name(np, "touch");
 	if (!np) {
 		dev_err(&pdev->dev, "Can't find touch node\n");
 		return -EINVAL;
@@ -144,13 +144,13 @@ static int pm860x_touch_dt_init(struct p
 	if (data) {
 		ret = pm860x_reg_write(i2c, PM8607_GPADC_MISC1, data);
 		if (ret < 0)
-			return -EINVAL;
+			goto err_put_node;
 	}
 	/* set tsi prebias time */
 	if (!of_property_read_u32(np, "marvell,88pm860x-tsi-prebias", &data)) {
 		ret = pm860x_reg_write(i2c, PM8607_TSI_PREBIAS, data);
 		if (ret < 0)
-			return -EINVAL;
+			goto err_put_node;
 	}
 	/* set prebias & prechg time of pen detect */
 	data = 0;
@@ -161,10 +161,18 @@ static int pm860x_touch_dt_init(struct p
 	if (data) {
 		ret = pm860x_reg_write(i2c, PM8607_PD_PREBIAS, data);
 		if (ret < 0)
-			return -EINVAL;
+			goto err_put_node;
 	}
 	of_property_read_u32(np, "marvell,88pm860x-resistor-X", res_x);
+
+	of_node_put(np);
+
 	return 0;
+
+err_put_node:
+	of_node_put(np);
+
+	return -EINVAL;
 }
 #else
 #define pm860x_touch_dt_init(x, y, z)	(-1)